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Android Studio 简单项目——简易计算器_androidstudio计算机项目源码(简易计算器app含源码+文档和ppt)

作者：我家小花儿 | 2024-03-27 15:57:51

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androidstudio计算机项目源码(简易计算器app含源码+文档和ppt)

Android Studio 简单项目——简易计算器

目录

Android Studio 简单项目——简易计算器

一、前言

二、设计界面

三、主要代码

四、完整资源

一、前言

软件：Android Studio

需求：学习Android Studio，做一个简易计算器深入学习

（附：刚开始学习，部分代码参考，在此基础上增删改）

主要功能实现：

1.简单计算器加减乘除

2.错误提示

3.追加模式

4.写入读取

二、设计界面

1.主界面

2.功能解释

①第一行输入数据

第二行为输出结果

②为错误提示行

如果除数为0则算式无意义，输出错误。如下图

③计算器键盘

CE 为清零 ， BA 为清除

①写入读取提示

② 读取成功，会出现读取算是

③计算表达式

三、主要代码

1.MainActivity

  1. package com.example.administrator.helloworld;
  2.  
  3. import android.os.Bundle;
  4. import android.support.design.widget.FloatingActionButton;
  5. import android.support.design.widget.Snackbar;
  6. import android.support.v7.app.AppCompatActivity;
  7. import android.support.v7.widget.Toolbar;
  8. import android.view.View;
  9. import android.view.Menu;
  10. import android.view.MenuItem;
  11.  
  12.  
  13. import android.app.Activity;
  14. import android.content.Context;
  15. import android.os.Bundle;
  16. import android.view.View;
  17. import android.view.View.OnClickListener;
  18. import android.widget.Button;
  19. import android.widget.CheckBox;
  20. import android.widget.EditText;
  21.  
  22. import java.io.FileInputStream;
  23. import java.io.FileNotFoundException;
  24. import java.io.FileOutputStream;
  25. import java.io.IOException;
  26.  
  27. public class MainActivity extends Activity {
  28.     /**
  29.      * Called when the activity is first created.
  30.      */
  31.     private EditText output = null;
  32.     private EditText input = null;
  33.     private Button btn0 = null;
  34.     private Button btn1 = null;
  35.     private Button btn2 = null;
  36.     private Button btn3 = null;
  37.     private Button btn4 = null;
  38.     private Button btn5 = null;
  39.     private Button btn6 = null;
  40.     private Button btn7 = null;
  41.     private Button btn8 = null;
  42.     private Button btn9 = null;
  43.     private Button btnadd = null;
  44.     private Button btnsubtract = null;
  45.     private Button btnmultiply = null;
  46.     private Button btndivide = null;
  47.     private Button btnclear = null;
  48.     private Button btnresult = null;
  49.     private Button btndot = null;
  50.     private Button btnback = null;
  51.     private EditText errorzero = null;
  52.  
  53.     private EditText resultText = null;
  54.     private Button writeButton = null;
  55.     private Button readButton = null;
  56.     private CheckBox appendBox = null;
  57.     private EditText textView = null;
  58.     private EditText displayView = null;
  59.     public String FILE_NAME = "fileDemo.txt";
  60.  
  61.  
  62.     private String str = "";//保存数字
  63.     private String strold = "";//原数字
  64.     private char act = ' ';//记录“加减乘除等于”符号
  65.     private int count = 0;//判断要计算的次数，如果超过一个符号，先算出来一部分
  66.     private Float result = null;//计算的输出结果
  67.     private Boolean errBoolean = false;//有错误的时候为true，无错为false
  68.     private Boolean flagBoolean = false;//一个标志，如果为true，可以响应运算消息，如果为false，不响应运算消息，只有前面是数字才可以响应运算消息
  69.     private Boolean flagDot = false; //小数点标志位
  70.  
  71.  
  72.     @Override
  73.     public void onCreate(Bundle savedInstanceState) {
  74.         super.onCreate(savedInstanceState);
  75.         setContentView(R.layout.activity_main);
  76.  
  77.         output = (EditText) findViewById(R.id.output);
  78.         input = (EditText) findViewById(R.id.input);
  79.  
  80.         errorzero = (EditText) findViewById(R.id.errorzero);
  81.         resultText = (EditText) findViewById(R.id.resultText);
  82.         writeButton = (Button) findViewById(R.id.writeButton);
  83.         readButton = (Button) findViewById(R.id.readButton);
  84.         textView = (EditText) findViewById(R.id.textView);
  85.         displayView = (EditText) findViewById(R.id.displayView);
  86.         appendBox = (CheckBox) findViewById(R.id.appendBox);
  87.  
  88.         btn0 = (Button) findViewById(R.id.zero);
  89.         btn1 = (Button) findViewById(R.id.one);
  90.         btn2 = (Button) findViewById(R.id.two);
  91.         btn3 = (Button) findViewById(R.id.three);
  92.         btn4 = (Button) findViewById(R.id.four);
  93.         btn5 = (Button) findViewById(R.id.five);
  94.         btn6 = (Button) findViewById(R.id.six);
  95.         btn7 = (Button) findViewById(R.id.seven);
  96.         btn8 = (Button) findViewById(R.id.eight);
  97.         btn9 = (Button) findViewById(R.id.nine);
  98.         btnadd = (Button) findViewById(R.id.add);
  99.         btnsubtract = (Button) findViewById(R.id.subtract);
  100.         btnmultiply = (Button) findViewById(R.id.multiply);
  101.         btndivide = (Button) findViewById(R.id.divide);
  102.         btnclear = (Button) findViewById(R.id.clear);
  103.         btnback = (Button) findViewById(R.id.back);
  104.         btnresult = (Button) findViewById(R.id.result);
  105.         btndot = (Button) findViewById(R.id.dot);
  106.         //设置按钮侦听事件
  107.         btn0.setOnClickListener(listener);
  108.         btn1.setOnClickListener(listener);
  109.         btn2.setOnClickListener(listener);
  110.         btn3.setOnClickListener(listener);
  111.         btn4.setOnClickListener(listener);
  112.         btn5.setOnClickListener(listener);
  113.         btn6.setOnClickListener(listener);
  114.         btn7.setOnClickListener(listener);
  115.         btn8.setOnClickListener(listener);
  116.         btn9.setOnClickListener(listener);
  117.         //执行运算
  118.         btnadd.setOnClickListener(listener);
  119.         btnsubtract.setOnClickListener(listener);
  120.         btnmultiply.setOnClickListener(listener);
  121.         btndivide.setOnClickListener(listener);
  122.         btnclear.setOnClickListener(listener);
  123.         btnresult.setOnClickListener(listener);
  124.         btnback.setOnClickListener(listener);
  125.  
  126.         btndot.setOnClickListener(listener);
  127.  
  128.         writeButton.setOnClickListener(writelistener);
  129.         readButton.setOnClickListener(readlistener);
  130.  
  131.  
  132.         // ATTENTION: This was auto-generated to implement the App Indexing API.
  133.         // See https://g.co/AppIndexing/AndroidStudio for more information.
  134.     }
  135.  
  136.  
  137.     private OnClickListener listener = new OnClickListener() {
  138.  
  139.         public void onClick(View v) {
  140.             // TODO Auto-generated method stub
  141.             switch (v.getId()) {
  142.                 //输入数字
  143.                 case R.id.zero:
  144.                     num(0);
  145.                     break;
  146.                 case R.id.one:
  147.                     num(1);
  148.                     break;
  149.                 case R.id.two:
  150.                     num(2);
  151.                     break;
  152.                 case R.id.three:
  153.                     num(3);
  154.                     break;
  155.                 case R.id.four:
  156.                     num(4);
  157.                     break;
  158.                 case R.id.five:
  159.                     num(5);
  160.                     break;
  161.                 case R.id.six:
  162.                     num(6);
  163.                     break;
  164.                 case R.id.seven:
  165.                     num(7);
  166.                     break;
  167.                 case R.id.eight:
  168.                     num(8);
  169.                     break;
  170.                 case R.id.nine:
  171.                     num(9);
  172.                     break;
  173.  
  174.                 case R.id.dot:
  175.                     dot();
  176.                     break;
  177.                 //执行运算
  178.                 case R.id.add:
  179.                     add();
  180.                     break;
  181.                 case R.id.subtract:
  182.                     sub();
  183.                     break;
  184.                 case R.id.multiply:
  185.                     multiply();
  186.                     break;
  187.                 case R.id.divide:
  188.                     divide();
  189.                     break;
  190.                 case R.id.clear:
  191.                     clear();
  192.                     break;
  193.                 case R.id.back:
  194.                     back();
  195.                     break;
  196.                 //计算结果
  197.                 case R.id.result:
  198.                     result();
  199.                     if (!errBoolean && flagBoolean) {
  200.                         output.setText(String.valueOf(result));
  201.                     }
  202.                     resultText.setText(strold + act + str + "=" + result+"                          ");
  203.                     break;
  204.  
  205.                 default:
  206.                     break;
  207.  
  208.             }
  209.             input.setText(strold + act + str);
  210.             output.setText(String.valueOf(result));
  211.  
  212.  
  213.         }
  214.     };
  215.  
  216.     private OnClickListener writelistener = new OnClickListener() {
  217.         @Override
  218.         public void onClick(View view) {
  219.             //textView.setText("");
  220.  
  221.             FileOutputStream fos = null;
  222.             try {
  223.                 if (appendBox.isChecked()) {
  224.                     fos = openFileOutput(FILE_NAME, Context.MODE_APPEND);
  225.                 } else {
  226.                     fos = openFileOutput(FILE_NAME, Context.MODE_PRIVATE);
  227.                 }
  228.                 String text = resultText.getText().toString();
  229.                 fos.write(text.getBytes());
  230.                 textView.setText("文件写入成功，写入长度：" + text.length());
  231.  
  232.             } catch (FileNotFoundException e) {
  233.                 e.printStackTrace();
  234.             } catch (IOException e) {
  235.                 e.printStackTrace();
  236.             }
  237.             finally {
  238.                 if (fos != null)
  239.                     try {
  240.                         fos.flush();
  241.                         fos.close();
  242.                     } catch (IOException e) {
  243.                         e.printStackTrace();
  244.                     }
  245.             }
  246.         }
  247.     };
  248.     private OnClickListener readlistener = new OnClickListener() {
  249.         @Override
  250.         public void onClick(View view) {
  251.  
  252.             displayView.setText("");
  253.             FileInputStream fis = null;
  254.             try {
  255.                 fis = openFileInput(FILE_NAME);
  256.                 if (fis.available() == 0) {
  257.                     return;
  258.                 }
  259.                 byte[] readBytes = new byte[fis.available()];
  260.                 while (fis.read(readBytes) != -1) {
  261.  
  262.                 }
  263.                 String text = new String(readBytes);
  264.                 displayView.setText(text);
  265.                 textView.setText("文件读取成功，写入长度：" + text.length());
  266.  
  267.             } catch (FileNotFoundException e) {
  268.                 e.printStackTrace();
  269.             } catch (IOException e) {
  270.                 e.printStackTrace();
  271.             }
  272.  
  273.         }
  274.     };
  275.  
  276.     private void dot() {
  277.         // TODO Auto-generated method stub
  278.  
  279.         if (!flagDot) {
  280.             str = str + ".";
  281.             flagBoolean = false;
  282.             flagDot = true;
  283.         }
  284.     }
  285.     private void back() {
  286.         str = strold = "";
  287.         count = 0;
  288.         act = ' ';
  289.         result = null;
  290.         flagBoolean = false;
  291.         flagDot = false;
  292.         resultText.setText("");
  293.         input.setText(strold + act + str);
  294.       /*  if(str==null){
  296.             str="";
  297.             input.setText("");
  298.         }
  299.         else if(str!=null&&!str.equals("")){
  300.             input.setText(str.substring(0,str.length()-1));
  301.         }
  302.         */
  303.  
  304.     }
  305.     private void clear() {
  306.         // TODO Auto-generated method stub
  307.         str = strold = "";
  308.         count = 0;
  309.         act = ' ';
  310.         result = null;
  311.         flagBoolean = false;
  312.         flagDot = false;
  313.         input.setText(strold + act + str);
  314.         output.setText("");
  315.         errorzero.setText("");
  316.         displayView.setText("");
  317.         textView.setText("");
  318.         resultText.setText("");
  319.     }
  320.  
  321.     private void divide() {
  322.         // TODO Auto-generated method stub
  323.         if (flagBoolean) {
  324.             check();
  325.             act = '/';
  326.             flagBoolean = false;
  327.         }
  328.     }
  329.  
  330.     private void multiply() {
  331.         // TODO Auto-generated method stub
  332.         if (flagBoolean) {
  333.             check();
  334.             act = '*';
  335.             flagBoolean = false;
  336.         }
  337.     }
  338.  
  339.     private void sub() {
  340.         // TODO Auto-generated method stub
  341.         if (flagBoolean) {
  342.             check();
  343.             act = '-';
  344.             flagBoolean = false;
  345.         }
  346.     }
  347.  
  348.     private void add() {
  349.         // TODO Auto-generated method stub
  350.         if (flagBoolean) {
  351.             check();
  352.             act = '+';
  353.             flagBoolean = false;
  354.         }
  355.     }
  356.  
  357.     private void check() {
  358.         // TODO Auto-generated method stub
  359.         if (count >= 1) {
  360.             result();
  361.             str = String.valueOf(result);
  362.         }
  363.         strold = str;
  364.         str = "";
  365.         count++;
  366.         flagDot = false;
  367.         errorzero.setText("");
  368.     }
  369.  
  370.     //计算输出结果
  371.     private void result() {
  372.         // TODO Auto-generated method stub
  373.         if (flagBoolean) {
  374.             Float a, b;
  375.  
  376.             a = Float.parseFloat(strold);
  377.             b = Float.parseFloat(str);
  378.  
  379.             if (b == 0 && act == '/') {
  380.                 clear();
  381.  
  382.                 errorzero.setText("除数不能为零!");
  383.  
  384.                 //errBoolean=true;
  385.             }
  386.  
  387.  
  388.             if (!errBoolean) {
  389.                 switch (act) {
  390.                     case '+':
  391.                         result = a + b;
  392.                         break;
  393.                     case '-':
  394.                         result = a - b;
  395.                         break;
  396.                     case '*':
  397.                         result = a * b;
  398.                         break;
  399.                     case '/':
  400.                         result = a / b;
  401.                         break;
  402.  
  403.                     default:
  404.                         break;
  405.                 }
  406.             }
  407.  
  408.  
  409.         }
  410.     }
  411.  
  412.     private void num(int i) {
  413.         // TODO Auto-generated method stub
  414.         str = str + String.valueOf(i);
  415.         flagBoolean = true;
  416.         errorzero.setText("");
  417.     }
  418.  
  419. }

2.activity_main.xml

  1. <?xml version="1.0" encoding="utf-8"?>
  2.  
  3. <ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
  4. android:layout_width="fill_parent"
  5. android:layout_height="wrap_content"
  6.     >
  7. <LinearLayout
  8.     android:layout_width="fill_parent"
  9.     android:layout_height="fill_parent"
  10.     android:orientation="vertical" >
  11.  
  12.     <EditText
  13.         android:id="@+id/input"
  14.         android:layout_width="fill_parent"
  15.         android:layout_height="wrap_content"
  16.         android:layout_gravity="center"
  17.         android:editable="false"
  18.         android:hint="@string/shuru" />
  19.  
  20.     <EditText
  21.         android:id="@+id/output"
  22.         android:layout_width="fill_parent"
  23.         android:layout_height="wrap_content"
  24.         android:layout_gravity="center"
  25.         android:editable="true"
  26.         android:gravity="right"
  27.         android:hint="@string/shuchu" />
  28.  
  29.     <EditText
  30.         android:id="@+id/errorzero"
  31.         android:layout_width="fill_parent"
  32.         android:layout_height="wrap_content"
  33.         android:layout_gravity="center"
  34.         android:editable="false"
  35.         android:gravity="center" />
  36.     <RelativeLayout
  37.         android:layout_width="fill_parent"
  38.         android:layout_height="wrap_content">
  39.  
  40.         <Button
  41.             android:id="@+id/seven"
  42.             android:layout_width="80dp"
  43.             android:layout_height="70dp"
  44.             android:layout_alignParentLeft="true"
  45.             android:text="@string/seven"
  46.             android:textSize="40sp" />
  47.  
  48.         <Button
  49.             android:id="@+id/eight"
  50.             android:layout_width="80dp"
  51.             android:layout_height="70dp"
  52.             android:layout_toRightOf="@id/seven"
  53.             android:text="@string/eight"
  54.             android:textSize="40sp" />
  55.  
  56.         <Button
  57.             android:id="@+id/nine"
  58.             android:layout_width="80dp"
  59.             android:layout_height="70dp"
  60.             android:layout_toRightOf="@id/eight"
  61.             android:text="@string/nine"
  62.             android:textSize="40sp" />
  63.  
  64.         <Button
  65.             android:id="@+id/add"
  66.             android:layout_width="80dp"
  67.             android:layout_height="70dp"
  68.             android:layout_alignParentRight="true"
  69.             android:layout_toRightOf="@id/nine"
  70.             android:background="#FF9800"
  71.             android:text="@string/add"
  72.             android:textSize="40sp" />
  73.  
  74.         <Button
  75.             android:id="@+id/four"
  76.             android:layout_width="80dp"
  77.             android:layout_height="70dp"
  78.             android:layout_below="@id/seven"
  79.             android:layout_alignParentLeft="true"
  80.             android:text="@string/four"
  81.             android:textSize="40sp" />
  82.  
  83.         <Button
  84.             android:id="@+id/five"
  85.             android:layout_width="80dp"
  86.             android:layout_height="70dp"
  87.             android:layout_below="@id/eight"
  88.             android:layout_toRightOf="@id/four"
  89.             android:text="@string/five"
  90.             android:textSize="40sp" />
  91.  
  92.         <Button
  93.             android:id="@+id/six"
  94.             android:layout_width="80dp"
  95.             android:layout_height="70dp"
  96.             android:layout_below="@id/nine"
  97.             android:layout_toRightOf="@id/five"
  98.             android:text="@string/six"
  99.             android:textSize="40sp" />
  100.  
  101.         <Button
  102.             android:id="@+id/subtract"
  103.             android:layout_width="80dp"
  104.             android:layout_height="70dp"
  105.             android:layout_below="@id/add"
  106.             android:layout_alignParentRight="true"
  107.             android:layout_toRightOf="@id/six"
  108.             android:background="#FF9800"
  109.             android:text="@string/subtract"
  110.             android:textSize="40sp" />
  111.  
  112.         <Button
  113.             android:id="@+id/one"
  114.             android:layout_width="80dp"
  115.             android:layout_height="70dp"
  116.             android:layout_below="@id/four"
  117.             android:layout_alignParentLeft="true"
  118.             android:text="@string/one"
  119.             android:textSize="40sp" />
  120.  
  121.         <Button
  122.             android:id="@+id/two"
  123.             android:layout_width="80dp"
  124.             android:layout_height="70dp"
  125.             android:layout_below="@id/five"
  126.             android:layout_toRightOf="@id/one"
  127.             android:text="@string/two"
  128.             android:textSize="40sp" />
  129.  
  130.         <Button
  131.             android:id="@+id/three"
  132.             android:layout_width="80dp"
  133.             android:layout_height="70dp"
  134.             android:layout_below="@id/six"
  135.             android:layout_toRightOf="@id/two"
  136.             android:text="@string/three"
  137.             android:textSize="40sp" />
  138.  
  139.         <Button
  140.             android:id="@+id/multiply"
  141.             android:layout_width="80dp"
  142.             android:layout_height="70dp"
  143.             android:layout_below="@id/subtract"
  144.             android:layout_alignParentRight="true"
  145.             android:layout_toRightOf="@id/three"
  146.             android:background="#FF9800"
  147.             android:text="@string/multiply"
  148.             android:textSize="40sp" />
  149.  
  150.         <Button
  151.             android:id="@+id/zero"
  152.             android:layout_width="240dp"
  153.             android:layout_height="70dp"
  154.             android:layout_below="@id/three"
  155.             android:layout_alignParentLeft="true"
  156.             android:text="@string/zero"
  157.             android:textSize="40sp" />
  158.  
  159.         <Button
  160.             android:id="@+id/clear"
  161.             android:layout_width="80dp"
  162.             android:layout_height="70dp"
  163.  
  164.             android:layout_below="@id/zero"
  165.             android:layout_alignParentLeft="true"
  166.             android:text="@string/clear"
  167.             android:textSize="40sp" />
  168.         <Button
  169.             android:id="@+id/back"
  170.             android:layout_width="80dp"
  171.             android:layout_height="70dp"
  172.             android:layout_toRightOf="@id/clear"
  173.             android:layout_below="@id/zero"
  174.             android:text="@string/back"
  175.             android:textSize="40sp" />
  176.  
  177.         <Button
  178.             android:id="@+id/result"
  179.             android:layout_width="80dp"
  180.             android:layout_height="70dp"
  181.             android:layout_below="@id/divide"
  182.             android:layout_alignParentRight="true"
  183.             android:layout_toRightOf="@id/dot"
  184.             android:background="#FFC107"
  185.             android:text="@string/result"
  186.             android:textSize="40sp" />
  187.  
  188.         <Button
  189.             android:id="@+id/divide"
  190.             android:layout_width="80dp"
  191.             android:layout_height="70dp"
  192.             android:layout_below="@id/multiply"
  193.             android:layout_alignParentRight="true"
  194.             android:layout_toRightOf="@id/zero"
  195.             android:background="#FF9800"
  196.             android:text="@string/divide"
  197.             android:textSize="40sp" />
  198.  
  199.         <Button
  200.             android:id="@+id/dot"
  201.             android:layout_width="80dp"
  202.             android:layout_height="70dp"
  203.             android:layout_below="@id/zero"
  204.             android:layout_toRightOf="@id/back"
  205.  
  206.  
  207.             android:text="@string/dot"
  208.             android:textSize="40sp" />
  209.  
  210.         <Button
  211.             android:id="@+id/writeButton"
  212.             android:layout_width="160dp"
  213.             android:layout_height="70dp"
  214.             android:layout_below="@id/result"
  215.             android:layout_alignParentLeft="true"
  216.             android:text="@string/write"
  217.             android:textSize="40sp" />
  218.  
  219.         <Button
  220.             android:id="@+id/readButton"
  221.             android:layout_width="170dp"
  222.             android:layout_height="70dp"
  223.             android:layout_below="@id/result"
  224.             android:layout_alignParentRight="true"
  225.             android:text="@string/read"
  226.             android:textSize="40sp" />
  227.  
  228.         <CheckBox
  229.             android:id="@+id/appendBox"
  230.             android:layout_width="80dp"
  231.             android:layout_height="70dp"
  232.             android:layout_below="@id/dot"
  233.             android:layout_toRightOf="@id/writeButton"
  234.             android:layout_alignParentBottom="true"
  235.  
  236.  
  237.             android:text="@string/appendBox" />
  238.  
  239.     </RelativeLayout>
  240.  
  241.     <EditText
  242.  
  243.         android:layout_width="match_parent"
  244.         android:layout_height="wrap_content"
  245.         android:id="@+id/textView" />
  246.  
  247.     <EditText
  248.  
  249.         android:id="@+id/displayView"
  250.         android:layout_width="match_parent"
  251.         android:layout_height="44dp" />
  252.  
  253.  
  254.     <EditText
  255.         android:id="@+id/resultText"
  256.         android:layout_width="fill_parent"
  257.         android:layout_height="45dp"
  258.  
  259.         android:layout_gravity="center"
  260.         android:editable="false"
  261.         android:gravity="left"
  262.         android:text="@string/resultText" />
  263. </LinearLayout>
  264. </ScrollView>

四、完整资源

https://download.csdn.net/download/qi2456/11203862

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