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Android studio实现简单的计算器

作者：IT小白 | 2024-03-12 08:45:29

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Android studio实现简单的计算器

目录

计算器1：

MainAcivity.java

activity_main.xml

UI界面 

计算器2：

MainActivity.java:

active_main.xml:

UI界面：

 

计算器1：

MainAcivity.java

  1. package com.example.lijiang.mycalculator;
  2.  
  3. import android.os.Bundle;
  4. import android.support.v7.app.AppCompatActivity;
  5. import android.view.View;
  6. import android.widget.Button;
  7. import android.widget.EditText;
  8. import java.lang.reflect.Method;
  9. import java.math.BigDecimal;
  10. import java.util.ArrayList;
  11. import java.util.List;
  12.  
  13.  
  14. public class MainActivity extends AppCompatActivity{
  15.  
  16.     private  StringBuilder show_equation=new StringBuilder();//显示运算式
  17.     private  ArrayList calculate_equation;//计算式
  18.     private  int signal=0;//为0 时表示刚输入状态；为1 时表示当前在输出结果上继续输入
  19.     @Override
  20.     protected void onCreate(Bundle savedInstanceState) {
  21.         super.onCreate(savedInstanceState);
  22.         setContentView(R.layout.activity_main);
  23.         //初始化
  24.         show_equation=new StringBuilder();
  25.         calculate_equation=new ArrayList<>();
  26.         Button zero=(Button)findViewById(R.id.zero);
  27.         Button one=(Button)findViewById(R.id.one);
  28.         Button two=(Button)findViewById(R.id.two);
  29.         Button three=(Button)findViewById(R.id.three);
  30.         Button four=(Button)findViewById(R.id.four);
  31.         Button five=(Button)findViewById(R.id.five);
  32.         Button six=(Button)findViewById(R.id.six);
  33.         Button seven=(Button)findViewById(R.id.seven);
  34.         Button eight=(Button)findViewById(R.id.eight);
  35.         Button nine=(Button)findViewById(R.id.nine);
  36.         Button cls=(Button)findViewById(R.id.cls);
  37.         Button div=(Button)findViewById(R.id.div);
  38.         Button mul=(Button)findViewById(R.id.mul);
  39.         Button backspace=(Button)findViewById(R.id.Backspace);
  40.         Button sub=(Button)findViewById(R.id.sub);
  41.         Button add=(Button)findViewById(R.id.add);
  42.         final Button equal=(Button)findViewById(R.id.equal);
  43.         final Button point=(Button)findViewById(R.id.spot);
  44.         final EditText result=(EditText)findViewById(R.id.result);
  45.         result.setCursorVisible(true);
  46.         disableShowInput(result);
  47.         //点击文本框时光标始终在文本末尾
  48.         result.setOnClickListener(new View.OnClickListener() {
  49.             @Override
  50.             public void onClick(View view) {
  51.                 result.setSelection(result.getText().length());
  52.             }
  53.         });
  54.         zero.setOnClickListener(new View.OnClickListener() {
  55.             @Override
  56.             public void onClick(View v){
  57.                 if(!(show_equation.toString().equals("0"))){
  58.                     if(signal==0){
  59.                         show_equation.append("0");
  60.                         result.setText(show_equation);
  61.                         result.setSelection(result.getText().length());
  62.                     }else{
  63.                         show_equation.delete(0,show_equation.length());
  64.                         show_equation.append("0");
  65.                         result.setText(show_equation);
  66.                         result.setSelection(result.getText().length());
  67.                         signal=0;
  68.                     }
  69.                 }
  70.             }
  71.         });
  72.         one.setOnClickListener(new View.OnClickListener() {
  73.             @Override
  74.             public void onClick(View v) {
  75.                 if(signal==0){
  76.                     show_equation.append("1");
  77.                     result.setText(show_equation);
  78.                     result.setSelection(result.getText().length());
  79.                 }else{
  80.                     show_equation.delete(0,show_equation.length());
  81.                     show_equation.append("1");
  82.                     result.setText(show_equation);
  83.                     result.setSelection(result.getText().length());
  84.                     signal=0;
  85.                 }
  86.             }
  87.         });
  88.         two.setOnClickListener(new View.OnClickListener() {
  89.             @Override
  90.             public void onClick(View v) {
  91.                 if(signal==0){
  92.                     show_equation.append("2");
  93.                     result.setText(show_equation);
  94.                     result.setSelection(result.getText().length());
  95.                 }else{
  96.                     show_equation.delete(0,show_equation.length());
  97.                     show_equation.append("2");
  98.                     result.setText(show_equation);
  99.                     result.setSelection(result.getText().length());
  100.                     signal=0;
  101.                 }
  102.             }
  103.         });
  104.         three.setOnClickListener(new View.OnClickListener() {
  105.             @Override
  106.             public void onClick(View v) {
  107.                 if(signal==0){
  108.                     show_equation.append("3");
  109.                     result.setText(show_equation);
  110.                     result.setSelection(result.getText().length());
  111.                 }else{
  112.                     show_equation.delete(0,show_equation.length());
  113.                     show_equation.append("3");
  114.                     result.setText(show_equation);
  115.                     result.setSelection(result.getText().length());
  116.                     signal=0;
  117.                 }
  118.             }
  119.         });
  120.         four.setOnClickListener(new View.OnClickListener() {
  121.             @Override
  122.             public void onClick(View v) {
  123.                 if(signal==0){
  124.                     show_equation.append("4");
  125.                     result.setText(show_equation);
  126.                     result.setSelection(result.getText().length());
  127.                 }else{
  128.                     show_equation.delete(0,show_equation.length());
  129.                     show_equation.append("4");
  130.                     result.setText(show_equation);
  131.                     result.setSelection(result.getText().length());
  132.                     signal=0;
  133.                 }
  134.             }
  135.         });
  136.         five.setOnClickListener(new View.OnClickListener() {
  137.             @Override
  138.             public void onClick(View v) {
  139.                 if(signal==0){
  140.                     show_equation.append("5");
  141.                     result.setText(show_equation);
  142.                     result.setSelection(result.getText().length());
  143.                 }else{
  144.                     show_equation.delete(0,show_equation.length());
  145.                     show_equation.append("5");
  146.                     result.setText(show_equation);
  147.                     result.setSelection(result.getText().length());
  148.                     signal=0;
  149.                 }
  150.             }
  151.         });
  152.         six.setOnClickListener(new View.OnClickListener() {
  153.             @Override
  154.             public void onClick(View v) {
  155.                 if(signal==0){
  156.                     show_equation.append("6");
  157.                     result.setText(show_equation);
  158.                     result.setSelection(result.getText().length());
  159.                 }else{
  160.                     show_equation.delete(0,show_equation.length());
  161.                     show_equation.append("6");
  162.                     result.setText(show_equation);
  163.                     result.setSelection(result.getText().length());
  164.                     signal=0;
  165.                 }
  166.             }
  167.         });
  168.         seven.setOnClickListener(new View.OnClickListener() {
  169.             @Override
  170.             public void onClick(View v) {
  171.                 if(signal==0){
  172.                     show_equation.append("7");
  173.                     result.setText(show_equation);
  174.                     result.setSelection(result.getText().length());
  175.                 }else{
  176.                     show_equation.delete(0,show_equation.length());
  177.                     show_equation.append("7");
  178.                     result.setText(show_equation);
  179.                     result.setSelection(result.getText().length());
  180.                     signal=0;
  181.                 }
  182.             }
  183.         });
  184.         eight.setOnClickListener(new View.OnClickListener() {
  185.             @Override
  186.             public void onClick(View v) {
  187.                 if(signal==0){
  188.                     show_equation.append("8");
  189.                     result.setText(show_equation);
  190.                     result.setSelection(result.getText().length());
  191.                 }else{
  192.                     show_equation.delete(0,show_equation.length());
  193.                     show_equation.append("8");
  194.                     result.setText(show_equation);
  195.                     result.setSelection(result.getText().length());
  196.                     signal=0;
  197.                 }
  198.             }
  199.         });
  200.         nine.setOnClickListener(new View.OnClickListener() {
  201.             @Override
  202.             public void onClick(View v) {
  203.                 if(signal==0){
  204.                     show_equation.append("9");
  205.                     result.setText(show_equation);
  206.                     result.setSelection(result.getText().length());
  207.                 }else{
  208.                     show_equation.delete(0,show_equation.length());
  209.                     show_equation.append("9");
  210.                     result.setText(show_equation);
  211.                     result.setSelection(result.getText().length());
  212.                     signal=0;
  213.                 }
  214.             }
  215.         });
  216.         cls.setOnClickListener(new View.OnClickListener() {
  217.             @Override
  218.             public void onClick(View v) {
  219.                 show_equation.delete(0,show_equation.length());
  220.                 calculate_equation.clear();
  221.                 signal=0;
  222.                 result.setText("");
  223.             }
  224.         });
  225.         backspace.setOnClickListener(new View.OnClickListener() {
  226.             @Override
  227.             public void onClick(View v) {
  228.                 if(!(show_equation.toString().equals(""))) {
  229.                     if(signal==0){
  230.                         show_equation.deleteCharAt(show_equation.length() - 1);
  231.                         result.setText(show_equation);
  232.                         result.setSelection(result.getText().length());
  233.                     }else{
  234.                         show_equation.delete(0,show_equation.length());
  235.                         result.setText("");
  236.                         signal=0;
  237.                     }
  238.                 }
  239.             }
  240.         });
  241.         point.setOnClickListener(new View.OnClickListener() {
  242.             @Override
  243.             public void onClick(View v) {
  244.                 if(signal==0){
  245.                     String a=show_equation.toString();
  246.                     if(a.equals("")){
  247.                         show_equation.append(".");
  248.                         result.setText(show_equation);
  249.                         result.setSelection(result.getText().length());
  250.                     }else{
  251.                         int i;
  252.                         char t='0';
  253.                         for(i=a.length();i>0;i--){
  254.                             t=a.charAt(i-1);
  255.                             if(t=='.'||t=='+'||t=='-'||t=='*'||t=='/')
  256.                                 break;
  257.                         }
  258.                         if(i==0){
  259.                             show_equation.append(".");
  260.                             result.setText(show_equation);
  261.                             result.setSelection(result.getText().length());
  262.                         }else if(t=='+'||t=='-'||t=='*'||t=='/'){
  263.                             show_equation.append(".");
  264.                             result.setText(show_equation);
  265.                             result.setSelection(result.getText().length());
  266.                         }
  267.                     }
  268.                 }else{
  269.                     show_equation.delete(0,show_equation.length());
  270.                     show_equation.append(".");
  271.                     result.setText(".");
  272.                     result.setSelection(result.getText().length());
  273.                     signal=0;
  274.                 }
  275.             }
  276.         });
  277.  
  278.         equal.setOnClickListener(new View.OnClickListener() {
  279.             @Override
  280.             public void onClick(View v) {
  281.                 //判断用户是否输入了内容
  282.                 if(!show_equation.toString().equals("")){
  283.                     signal=1;
  284.                     char temp=show_equation.charAt(show_equation.length()-1);
  285.                     if(show_equation.charAt(0)=='-')
  286.                         show_equation.insert(0,"0");
  287.                     if(temp=='+'||temp=='-')
  288.                         show_equation.append("0");
  289.                     if(temp=='*'||temp=='/')
  290.                         show_equation.append("1");
  291.                     StringBuilder temp1=new StringBuilder();
  292.                     for(int i=0;i<show_equation.length();i++){
  293.                         if(show_equation.charAt(i)>='0'&&show_equation.charAt(i)<='9'||show_equation.charAt(i)=='.'){
  294.                             temp1.append(String.valueOf(show_equation.charAt(i)));
  295.                         }else if(show_equation.charAt(i)=='N'){
  296.                             calculate_equation.add("NaN");
  297.                             //跳过2个字符
  298.                             i=i+2;
  299.                         }else if(show_equation.charAt(i)=='∞'){
  300.                             calculate_equation.add("∞");
  301.                         }
  302.                         else
  303.                         {
  304.                             if(temp1.length()!=0){
  305.                                 calculate_equation.add(temp1.toString());
  306.                                 temp1.delete(0,temp1.length());
  307.                             }
  308.                             calculate_equation.add(String.valueOf(show_equation.charAt(i)));
  309.                         }
  310.                     }
  311.                     if(temp1.length()!=0){
  312.                         calculate_equation.add(temp1.toString());
  313.                     }
  314.                     calculate_equation.add("#");
  315.                     String temp8=calculate(calculate_equation);
  316.                     result.setText(temp8);
  317.                     result.setSelection(result.getText().length());
  318.                     show_equation.delete(0,show_equation.length());
  319.                     calculate_equation.clear();
  320.                     show_equation.append(temp8);
  321.                 }
  322.             }
  323.         });
  324.         add.setOnClickListener(new View.OnClickListener() {
  325.             @Override
  326.             public void onClick(View v) {
  327.                 //判断用户是否输入了内容
  328.                 if(!(show_equation.toString().equals(""))) {
  329.                     signal=0;
  330.                     char temp=show_equation.charAt(show_equation.length()-1);
  331.                     if(temp=='+'||temp=='-'||temp=='*'||temp=='/')
  332.                     {
  333.                         show_equation.deleteCharAt(show_equation.length()-1);
  334.                         show_equation.append("+");
  335.                     }
  336.                     else
  337.                         show_equation.append("+");
  338.                     result.setText(show_equation);
  339.                     result.setSelection(result.getText().length());
  340.                 }
  341.             }
  342.         });
  343.         sub.setOnClickListener(new View.OnClickListener() {
  344.             @Override
  345.             public void onClick(View v) {
  346.                 //判断用户是否输入了内容
  347.                 if(!(show_equation.toString().equals(""))) {
  348.                     signal=0;
  349.                     char temp=show_equation.charAt(show_equation.length()-1);
  350.                     if(temp=='+'||temp=='-'||temp=='*'||temp=='/')
  351.                     {
  352.                         show_equation.deleteCharAt(show_equation.length()-1);
  353.                         show_equation.append("-");
  354.                     }
  355.                     else
  356.                         show_equation.append("-");
  357.                     result.setText(show_equation);
  358.                     result.setSelection(result.getText().length());
  359.                 }
  360.             }
  361.         });
  362.  
  363.         mul.setOnClickListener(new View.OnClickListener() {
  364.             @Override
  365.             public void onClick(View v) {
  366.                 //判断用户是否输入了内容
  367.                 if(!(show_equation.toString().equals(""))) {
  368.                     signal=0;
  369.                     char temp=show_equation.charAt(show_equation.length()-1);
  370.                     if(temp=='+'||temp=='-'||temp=='*'||temp=='/')
  371.                     {
  372.                         show_equation.deleteCharAt(show_equation.length()-1);
  373.                         show_equation.append("*");
  374.                     }
  375.                     else
  376.                         show_equation.append("*");
  377.                     result.setText(show_equation);
  378.                     result.setSelection(result.getText().length());
  379.                 }
  380.             }
  381.         });
  382.  
  383.         div.setOnClickListener(new View.OnClickListener() {
  384.             @Override
  385.             public void onClick(View v) {
  386.                 //判断用户是否输入了内容
  387.                 if(!(show_equation.toString().equals(""))) {
  388.                     signal=0;
  389.                     char temp=show_equation.charAt(show_equation.length()-1);
  390.                     if(temp=='+'||temp=='-'||temp=='*'||temp=='/')
  391.                     {
  392.                         show_equation.deleteCharAt(show_equation.length()-1);
  393.                         show_equation.append("/");
  394.                     }
  395.                     else
  396.                         show_equation.append("/");
  397.                     result.setText(show_equation);
  398.                     result.setSelection(result.getText().length());
  399.                 }
  400.             }
  401.         });
  402.     }
  403.     protected boolean operatorPriorityCompare(char operator1,char operator2)
  404.     {
  405.         int o1=0;
  406.         int o2=0;
  407.         switch (operator1){
  408.             case '+':{o1=0;break;}
  409.             case '-':{o1=0;break;}
  410.             case '*':{o1=1;break;}
  411.             case '/':{o1=1;break;}
  412.         }
  413.         switch (operator2){
  414.             case '+':{o2=0;break;}
  415.             case '-':{o2=0;break;}
  416.             case '*':{o2=1;break;}
  417.             case '/':{o2=1;break;}
  418.         }
  419.         if(o1<=o2)
  420.         {
  421.             return false;
  422.         }
  423.         else
  424.             return true;
  425.     }
  426.     //相加
  427.     public static Double Add(Double d1,Double d2) {
  428.         if(d1==Double.NEGATIVE_INFINITY||d1==Double.POSITIVE_INFINITY||d2==Double.NEGATIVE_INFINITY||d2==Double.POSITIVE_INFINITY){
  429.             return d1+d2;
  430.         }
  431.         if(String.valueOf(d1).equals("NaN")||String.valueOf(d1).equals("NaN")){
  432.             return d1+d2;
  433.         }
  434.         BigDecimal b1 = new BigDecimal(Double.toString(d1));
  435.         BigDecimal b2 = new BigDecimal(Double.toString(d2));
  436.         return b1.add(b2).doubleValue();
  437.     }
  438.     //相减
  439.     public static Double Sub(Double d1,Double d2){
  440.         if(d1==Double.NEGATIVE_INFINITY||d1==Double.POSITIVE_INFINITY||d2==Double.NEGATIVE_INFINITY||d2==Double.POSITIVE_INFINITY){
  441.             return d1-d2;
  442.         }
  443.         if(String.valueOf(d1).equals("NaN")||String.valueOf(d1).equals("NaN")){
  444.             return d1-d2;
  445.         }
  446.         if(String.valueOf(d1).equals("NaN")||String.valueOf(d1).equals("NaN")){
  447.             return d1*d2;
  448.         }
  449.         BigDecimal b1=new BigDecimal(Double.toString(d1));
  450.         BigDecimal b2=new BigDecimal(Double.toString(d2));
  451.         return b1.subtract(b2).doubleValue();
  452.     }
  453.     //相乘
  454.     public static Double Mul(Double d1,Double d2){
  455.         if(d1==Double.NEGATIVE_INFINITY||d1==Double.POSITIVE_INFINITY||d2==Double.NEGATIVE_INFINITY||d2==Double.POSITIVE_INFINITY){
  456.             return d1*d2;
  457.         }
  458.         if(String.valueOf(d1).equals("NaN")||String.valueOf(d1).equals("NaN")){
  459.             return d1*d2;
  460.         }
  461.         BigDecimal b1=new BigDecimal(Double.toString(d1));
  462.         BigDecimal b2=new BigDecimal(Double.toString(d2));
  463.         return b1.multiply(b2).setScale(8).doubleValue();
  464.     }
  465.     //相除
  466.     public static Double Div(Double d1,Double d2){
  467.         if(d1==Double.NEGATIVE_INFINITY||d1==Double.POSITIVE_INFINITY||d2==Double.NEGATIVE_INFINITY||d2==Double.POSITIVE_INFINITY){
  468.             return d1/d2;
  469.         }
  470.         if(String.valueOf(d1).equals("NaN")||String.valueOf(d1).equals("NaN")){
  471.             return d1/d2;
  472.         }
  473.         if(d1==0.0&&d2==0.0){
  474.             return Double.NaN;
  475.         }
  476.         if(d2==0.0){
  477.             return d1/d2;
  478.         }
  479.         BigDecimal b1=new BigDecimal(Double.toString(d1));
  480.         BigDecimal b2=new BigDecimal(Double.toString(d2));
  481.         return b1.divide(b2,8,BigDecimal.ROUND_HALF_UP).doubleValue();
  482.     }
  483.     protected String calculate(ArrayList equation){
  484.         Double temp2;
  485.         Double temp3;
  486.         Double result;
  487.         List operator=new ArrayList();
  488.         List<Double> operand=new ArrayList();
  489.         for(int i=0;i<equation.size();i++)
  490.         {
  491.             String temp4=(String) equation.get(i);
  492.             if(temp4.equals("+")||temp4.equals("-")||temp4.equals("*")||temp4.equals("/"))
  493.             {
  494.                 if(operator.size()>0)
  495.                 {
  496.                     String temp5=operator.get(operator.size()-1).toString();
  497.                     while(!(operatorPriorityCompare(temp4.charAt(0),temp5.charAt(0)))&&operator.size()>0)
  498.                     {
  499.                         operator.remove(operator.size()-1);
  500.                         temp3=operand.get(operand.size()-1);
  501.                         operand.remove(operand.size()-1);
  502.                         temp2=operand.get(operand.size()-1);
  503.                         operand.remove(operand.size()-1);
  504.                         switch (temp5.charAt(0)){
  505.                             case '+':{result=Add(temp2,temp3);operand.add(result);break;}
  506.                             case '-':{result=Sub(temp2,temp3);operand.add(result);break;}
  507.                             case '*':{result=Mul(temp2,temp3);operand.add(result);break;}
  508.                             case '/':{result=Div(temp2,temp3);operand.add(result);break;}
  509.                         }
  510.                         if(operator.size()>0)
  511.                         {
  512.                             temp5=operator.get(operator.size()-1).toString();
  513.                         }
  514.                         else
  515.                             break;
  516.                     }
  517.                     operator.add(temp4);
  518.                 }
  519.                 else
  520.                     operator.add(temp4);
  521.             }
  522.             else if(temp4.equals("#"))
  523.             {
  524.                 while(operator.size()>0)
  525.                 {
  526.                     String temp6=(String)operator.get(operator.size()-1);
  527.                     operator.remove(operator.size()-1);
  528.                     temp3=operand.get(operand.size()-1);
  529.                     operand.remove(operand.size()-1);
  530.                     temp2=operand.get(operand.size()-1);
  531.                     operand.remove(operand.size()-1);
  532.                     switch (temp6.charAt(0)){
  533.                         case '+':{result=Add(temp2,temp3);operand.add(result);break;}
  534.                         case '-':{result=Sub(temp2,temp3);operand.add(result);break;}
  535.                         case '*':{result=Mul(temp2,temp3);operand.add(result);break;}
  536.                         case '/':{result=Div(temp2,temp3);operand.add(result);break;}
  537.                     }
  538.                 }
  539.             }
  540.             else
  541.             {
  542.                 if(temp4.equals("NaN")){
  543.                     operand.add(Double.NaN);
  544.                 }else if(temp4.equals("∞")){
  545.                     operand.add(Double.POSITIVE_INFINITY);
  546.                 }else{
  547.                     operand.add(Double.parseDouble(temp4));
  548.                 }
  549.             }
  550.         }
  551.         if(operand.get(0)==Double.NEGATIVE_INFINITY) return "-∞";
  552.         if(operand.get(0)==Double.POSITIVE_INFINITY) return "∞";
  553.         return operand.get(0).toString();
  554.     }
  555.     //当API最低版小于21时使用这个函数实现点击文本框不弹出键盘
  556.     public void disableShowInput(EditText et) {
  557.         Class<EditText> cls = EditText.class;
  558.         Method method;
  559.         try {
  560.             method = cls.getMethod("setShowSoftInputOnFocus", boolean.class);
  561.             method.setAccessible(true);
  562.             method.invoke(et, false);
  563.         } catch (Exception e) {
  564.             e.printStackTrace();
  565.         }
  566.     }
  567. }

activity_main.xml

  1. <?xml version="1.0" encoding="utf-8"?>
  2. <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  3.     android:orientation="vertical"
  4.     android:layout_width="match_parent"
  5.     android:layout_height="match_parent">
  6.  
  7.     <EditText
  8.         android:id="@+id/result"
  9.         android:layout_width="match_parent"
  10.         android:layout_height="wrap_content"
  11.         android:textSize="40sp"
  12.         android:enabled="false"/>
  13.     <LinearLayout
  14.         android:layout_width="match_parent"
  15.         android:layout_height="0dp"
  16.         android:layout_weight="1"
  17.         android:orientation="horizontal">
  18.  
  19.         <Button
  20.             android:id="@+id/cls"
  21.             android:layout_width="0dp"
  22.             android:layout_height="match_parent"
  23.             android:layout_weight="1"
  24.             android:textSize="20sp"
  25.             android:text="C"
  26.  
  27.             android:textColor="#ffffff"/>
  28.         <Button
  29.             android:id="@+id/div"
  30.             android:layout_width="0dp"
  31.             android:layout_height="match_parent"
  32.             android:layout_weight="1"
  33.             android:textSize="20sp"
  34.             android:text="/"
  35.  
  36.             android:textColor="#ffffff"/>
  37.         <Button
  38.             android:id="@+id/mul"
  39.             android:layout_width="0dp"
  40.             android:layout_height="match_parent"
  41.             android:layout_weight="1"
  42.             android:textSize="20sp"
  43.             android:text="*"
  44.  
  45.             android:textColor="#ffffff"/>
  46.         <Button
  47.             android:id="@+id/Backspace"
  48.             android:layout_width="0dp"
  49.             android:layout_height="match_parent"
  50.             android:layout_weight="1"
  51.             android:textSize="20sp"
  52.             android:text="Backspace"
  53.             android:textAllCaps="false"
  54.  
  55.             android:textColor="#ffffff"/>
  56.     </LinearLayout>
  57.  
  58.     <LinearLayout
  59.         android:layout_width="match_parent"
  60.         android:layout_height="0dp"
  61.         android:layout_weight="1"
  62.         android:orientation="horizontal">
  63.  
  64.         <Button
  65.             android:id="@+id/seven"
  66.             android:layout_width="0dp"
  67.             android:layout_height="match_parent"
  68.             android:layout_weight="1"
  69.             android:textSize="20sp"
  70.             android:text="7"
  71.  
  72.             android:textColor="#ffffff"/>
  73.         <Button
  74.             android:id="@+id/eight"
  75.             android:layout_width="0dp"
  76.             android:layout_height="match_parent"
  77.             android:layout_weight="1"
  78.             android:textSize="20sp"
  79.             android:text="8"
  80.  
  81.             android:textColor="#ffffff"/>
  82.         <Button
  83.             android:id="@+id/nine"
  84.             android:layout_width="0dp"
  85.             android:layout_height="match_parent"
  86.             android:layout_weight="1"
  87.             android:textSize="20sp"
  88.             android:text="9"
  89.  
  90.             android:textColor="#ffffff"/>
  91.         <Button
  92.             android:id="@+id/sub"
  93.             android:layout_width="0dp"
  94.             android:layout_height="match_parent"
  95.             android:layout_weight="1"
  96.             android:textSize="20sp"
  97.             android:text="-"
  98.  
  99.             android:textColor="#ffffff"/>
  100.     </LinearLayout>
  101.  
  102.     <LinearLayout
  103.         android:layout_width="match_parent"
  104.         android:layout_height="0dp"
  105.         android:layout_weight="1"
  106.         android:orientation="horizontal">
  107.  
  108.         <Button
  109.             android:id="@+id/four"
  110.             android:layout_width="0dp"
  111.             android:layout_height="match_parent"
  112.             android:layout_weight="1"
  113.             android:textSize="20sp"
  114.             android:text="4"
  115.  
  116.             android:textColor="#ffffff"/>
  117.         <Button
  118.             android:id="@+id/five"
  119.             android:layout_width="0dp"
  120.             android:layout_height="match_parent"
  121.             android:layout_weight="1"
  122.             android:textSize="20sp"
  123.             android:text="5"
  124.  
  125.             android:textColor="#ffffff"/>
  126.         <Button
  127.             android:id="@+id/six"
  128.             android:layout_width="0dp"
  129.             android:layout_height="match_parent"
  130.             android:layout_weight="1"
  131.             android:textSize="20sp"
  132.             android:text="6"
  133.  
  134.             android:textColor="#ffffff"/>
  135.         <Button
  136.             android:id="@+id/add"
  137.             android:layout_width="0dp"
  138.             android:layout_height="match_parent"
  139.             android:layout_weight="1"
  140.             android:textSize="20sp"
  141.             android:text="+"
  142.  
  143.             android:textColor="#ffffff"/>
  144.     </LinearLayout>
  145.  
  146.     <LinearLayout
  147.         android:layout_width="match_parent"
  148.         android:layout_height="0dp"
  149.         android:layout_weight="2"
  150.         android:orientation="horizontal">
  151.  
  152.         <LinearLayout
  153.             android:layout_width="0dp"
  154.             android:layout_height="match_parent"
  155.             android:layout_weight="1"
  156.             android:orientation="vertical">
  157.  
  158.             <LinearLayout
  159.                 android:layout_width="match_parent"
  160.                 android:layout_height="1dp"
  161.                 android:layout_weight="1"
  162.                 android:orientation="horizontal">
  163.                 <Button
  164.                     android:id="@+id/one"
  165.                     android:layout_width="0dp"
  166.                     android:layout_height="match_parent"
  167.                     android:layout_weight="1"
  168.                     android:textSize="20sp"
  169.                     android:text="1"
  170.  
  171.                     android:textColor="#ffffff"/>
  172.                 <Button
  173.                     android:id="@+id/two"
  174.                     android:layout_width="0dp"
  175.                     android:layout_height="match_parent"
  176.                     android:layout_weight="1"
  177.                     android:textSize="20sp"
  178.                     android:text="2"
  179.  
  180.                     android:textColor="#ffffff"/>
  181.             </LinearLayout>
  182.             <LinearLayout
  183.                 android:layout_width="match_parent"
  184.                 android:layout_height="1dp"
  185.                 android:layout_weight="1">
  186.                 <Button
  187.                     android:id="@+id/zero"
  188.                     android:layout_width="match_parent"
  189.                     android:layout_height="match_parent"
  190.                     android:text="0"
  191.                     android:textSize="20sp"
  192.  
  193.                     android:textColor="#ffffff"/>
  194.             </LinearLayout>
  195.         </LinearLayout>
  196.         <LinearLayout
  197.             android:layout_width="0dp"
  198.             android:layout_height="match_parent"
  199.             android:layout_weight="1"
  200.             android:orientation="horizontal">
  201.             <LinearLayout
  202.                 android:layout_width="0dp"
  203.                 android:layout_height="match_parent"
  204.                 android:layout_weight="1"
  205.                 android:orientation="vertical">
  206.                 <Button
  207.                     android:id="@+id/three"
  208.                     android:layout_width="match_parent"
  209.                     android:layout_height="1dp"
  210.                     android:layout_weight="1"
  211.                     android:text="3"
  212.                     android:textSize="20sp"
  213.  
  214.                     android:textColor="#ffffff"/>
  215.                 <Button
  216.                     android:id="@+id/spot"
  217.                     android:layout_width="match_parent"
  218.                     android:layout_height="1dp"
  219.                     android:layout_weight="1"
  220.                     android:text="."
  221.                     android:textSize="20sp"
  222.  
  223.                     android:textColor="#ffffff"/>
  224.             </LinearLayout>
  225.             <LinearLayout
  226.                 android:layout_width="0dp"
  227.                 android:layout_height="match_parent"
  228.                 android:layout_weight="1">
  229.                 <Button
  230.                     android:id="@+id/equal"
  231.                     android:layout_width="match_parent"
  232.                     android:layout_height="match_parent"
  233.                     android:text="="
  234.                     android:textSize="20sp"
  235.  
  236.                     android:textColor="#ffffff"/>
  237.             </LinearLayout>
  238.         </LinearLayout>
  239.     </LinearLayout>
  240. </LinearLayout>

UI界面 

计算器2：

MainActivity.java:

  1. package com.example.yuanmei.yuanmeicalculatorproject;
  2.  
  3.  
  4.  
  5. import android.app.Activity;
  6. import android.os.Bundle;
  7. import android.view.View;
  8. import android.widget.Button;
  9. import android.widget.TextView;
  10.  
  11. public class MainActivity extends Activity {
  12.     private TextView textView;
  13.     private String str,num1,num2;
  14.     private double result;
  15.     private boolean addNum;
  16.     @Override
  17.     protected void onCreate(Bundle savedInstanceState) {
  18.         super.onCreate(savedInstanceState);
  19.         setContentView(R.layout.activity_main);
  20.         textView = (TextView) findViewById(R.id.textView);
  21.         addNum = true;
  22.     }
  23.  
  24.     public void onClick(View v){
  25.         str = (String) textView.getText();
  26.         switch (v.getId()) {
  27.             case R.id.btn_cle:
  28.                 textView.setText("");
  29.                 break;
  30.             case R.id.btn_del:
  31.                 if(!str.equals("") && str != null){
  32.                     textView.setText(str.substring(0, str.length()-1));
  33.                 }
  34.                 break;
  35.             case R.id.btn_equ:
  36.                 if(str.contains("+")){
  37.                     getResult(num1, num2, "+");
  38.                 }
  39.                 else if(str.contains("-")){
  40.                     getResult(num1, num2, "-");
  41.                 }
  42.                 else if(str.contains("×")){
  43.                     getResult(num1, num2, "×");
  44.                 }
  45.                 else if(str.contains("÷")){
  46.                     getResult(num1, num2, "÷");
  47.                 }
  48.                 else {
  49.                     return;
  50.                 }
  51.                 break;
  52.             case R.id.btn_add:
  53.             case R.id.btn_sub:
  54.             case R.id.btn_mul:
  55.             case R.id.btn_div:
  56.                 if (str.contains("+")||str.contains("-")||str.contains("×")||str.contains("÷"))
  57.                     return;
  58.                 else
  59.                     textView.setText(str+((Button)v).getText());
  60.                 if(!addNum)
  61.                     addNum = true;
  62.                 break;
  63.             default:
  64.                 if (addNum) {
  65.                     textView.setText(str+((Button)v).getText());
  66.                 }else{
  67.                     textView.setText(((Button)v).getText());
  68.                     addNum = true;
  69.                 }
  70.                 break;
  71.         }
  72.     }
  73.     private void getResult(String num1,String num2,String op) {
  74.         num1 = str.substring(0,str.indexOf(op));
  75.         num2 = str.substring(str.indexOf(op)+1);
  76.         try {
  77.             double n1 = Double.parseDouble(num1);
  78.             double n2 = Double.parseDouble(num2);
  79.             if (op.equals("+")) {
  80.                 result = n1+n2;
  81.             }else if(op.equals("-")){
  82.                 result = n1-n2;
  83.             }else if(op.equals("×")){
  84.                 result = n1*n2;
  85.             }else if(op.equals("÷")){
  86.                 result = n1/n2;
  87.             }else {
  88.                 return;
  89.             }
  90.  
  91.             String r = result+"";
  92.             if(r.contains(".")&&r.substring(r.length()-1).equals("0")){
  93.                 r = r.substring(0,r.indexOf("."));
  94.             }
  95.             textView.setText(r);
  96.             addNum = false;
  97.         } catch (Exception e) {
  98.             return;
  99.         }
  100.     }
  101. }

active_main.xml:

  1. <?xml version="1.0" encoding="utf-8"?>
  2. <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  3.     xmlns:tools="http://schemas.android.com/tools"
  4.     android:id="@+id/LinearLayout1"
  5.     android:layout_width="match_parent"
  6.     android:layout_height="match_parent"
  7.     android:orientation="vertical"
  8.  
  9.     tools:context=".MainActivity" >
  10.  
  11.     <TextView
  12.         android:id="@+id/textView"
  13.         android:layout_width="match_parent"
  14.         android:layout_height="wrap_content"
  15.         android:gravity="right"
  16.         android:height="40dp"
  17.         android:textSize="30sp" />
  18.  
  19.     <TableLayout
  20.         android:layout_width="match_parent"
  21.         android:layout_height="wrap_content"
  22.         android:stretchColumns="*" >
  23.  
  24.         <TableRow
  25.             android:id="@+id/tableRow1"
  26.             android:layout_width="match_parent"
  27.             android:layout_height="wrap_content" >
  28.  
  29.             <Button
  30.                 android:id="@+id/btn_cle"
  31.                 android:layout_width="wrap_content"
  32.                 android:layout_height="wrap_content"
  33.                 android:layout_span="2"
  34.                 android:onClick="onClick"
  35.                 android:text="CLEAR" />
  36.  
  37.             <Button
  38.                 android:id="@+id/btn_del"
  39.                 android:layout_width="wrap_content"
  40.                 android:layout_height="wrap_content"
  41.                 android:layout_span="2"
  42.                 android:onClick="onClick"
  43.                 android:text="☜" />
  44.         </TableRow>
  45.  
  46.         <TableRow
  47.             android:id="@+id/tableRow2"
  48.             android:layout_width="match_parent"
  49.             android:layout_height="wrap_content" >
  50.  
  51.             <Button
  52.                 android:id="@+id/btn_7"
  53.                 android:layout_width="wrap_content"
  54.                 android:layout_height="wrap_content"
  55.                 android:onClick="onClick"
  56.                 android:text="7" />
  57.  
  58.             <Button
  59.                 android:id="@+id/btn_8"
  60.                 android:layout_width="wrap_content"
  61.                 android:layout_height="wrap_content"
  62.                 android:onClick="onClick"
  63.                 android:text="8" />
  64.  
  65.             <Button
  66.                 android:id="@+id/btn_9"
  67.                 android:layout_width="wrap_content"
  68.                 android:layout_height="wrap_content"
  69.                 android:onClick="onClick"
  70.                 android:text="9" />
  71.  
  72.             <Button
  73.                 android:id="@+id/btn_div"
  74.                 android:layout_width="wrap_content"
  75.                 android:layout_height="wrap_content"
  76.                 android:onClick="onClick"
  77.                 android:text="÷" />
  78.         </TableRow>
  79.  
  80.         <TableRow
  81.             android:id="@+id/tableRow3"
  82.             android:layout_width="wrap_content"
  83.             android:layout_height="wrap_content" >
  84.  
  85.             <Button
  86.                 android:id="@+id/btn_4"
  87.                 android:layout_width="wrap_content"
  88.                 android:layout_height="wrap_content"
  89.                 android:onClick="onClick"
  90.                 android:text="4" />
  91.  
  92.             <Button
  93.                 android:id="@+id/btn_5"
  94.                 android:layout_width="wrap_content"
  95.                 android:layout_height="wrap_content"
  96.                 android:onClick="onClick"
  97.                 android:text="5" />
  98.  
  99.             <Button
  100.                 android:id="@+id/btn_6"
  101.                 android:layout_width="wrap_content"
  102.                 android:layout_height="wrap_content"
  103.                 android:onClick="onClick"
  104.                 android:text="6" />
  105.  
  106.             <Button
  107.                 android:id="@+id/btn_mul"
  108.                 android:layout_width="wrap_content"
  109.                 android:layout_height="wrap_content"
  110.                 android:onClick="onClick"
  111.                 android:text="×" />
  112.         </TableRow>
  113.  
  114.         <TableRow
  115.             android:id="@+id/tableRow4"
  116.             android:layout_width="wrap_content"
  117.             android:layout_height="wrap_content" >
  118.  
  119.             <Button
  120.                 android:id="@+id/btn_1"
  121.                 android:layout_width="wrap_content"
  122.                 android:layout_height="wrap_content"
  123.                 android:onClick="onClick"
  124.                 android:text="1" />
  125.  
  126.             <Button
  127.                 android:id="@+id/btn_2"
  128.                 android:layout_width="wrap_content"
  129.                 android:layout_height="wrap_content"
  130.                 android:onClick="onClick"
  131.                 android:text="2" />
  132.  
  133.             <Button
  134.                 android:id="@+id/btn_3"
  135.                 android:layout_width="wrap_content"
  136.                 android:layout_height="wrap_content"
  137.                 android:onClick="onClick"
  138.                 android:text="3" />
  139.  
  140.             <Button
  141.                 android:id="@+id/btn_sub"
  142.                 android:layout_width="wrap_content"
  143.                 android:layout_height="wrap_content"
  144.                 android:onClick="onClick"
  145.                 android:text="-" />
  146.         </TableRow>
  147.  
  148.         <TableRow
  149.             android:id="@+id/tableRow5"
  150.             android:layout_width="wrap_content"
  151.             android:layout_height="wrap_content" >
  152.  
  153.             <Button
  154.                 android:id="@+id/btn_point"
  155.                 android:layout_width="wrap_content"
  156.                 android:layout_height="wrap_content"
  157.                 android:onClick="onClick"
  158.                 android:text="." />
  159.  
  160.             <Button
  161.                 android:id="@+id/btn_0"
  162.                 android:layout_width="wrap_content"
  163.                 android:layout_height="wrap_content"
  164.                 android:onClick="onClick"
  165.                 android:text="0" />
  166.  
  167.             <Button
  168.                 android:id="@+id/btn_equ"
  169.                 android:layout_width="wrap_content"
  170.                 android:layout_height="wrap_content"
  171.                 android:onClick="onClick"
  172.                 android:text="=" />
  173.  
  174.             <Button
  175.                 android:id="@+id/btn_add"
  176.                 android:layout_width="wrap_content"
  177.                 android:layout_height="wrap_content"
  178.                 android:onClick="onClick"
  179.                 android:text="+" />
  180.         </TableRow>
  181.     </TableLayout>
  182.  
  183. </LinearLayout>

UI界面：

 

 

 

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