Android studio（一）按钮监听的三种方式_android studio 按钮监听

第一种方法：public class Activity2 extends AppCompatActivity implements View.OnClickListener
设置监听后，用id进行分别寻址

package com.example.test921;

import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {
      private TextView textView;
      private EditText editText;
      private Button bnt;
      private Button bnt2;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textView=this.findViewById(R.id.textView);
        editText=this.findViewById(R.id.editText);
        bnt=this.findViewById(R.id.button);
        bnt2=this.findViewById(R.id.button2);
        //设置按钮的监听，使用共同的监听方法，再用if else根据id寻址不同的button
        bnt.setOnClickListener(this);
        bnt2.setOnClickListener(this);
    }
    @Override
    public void onClick(View view)
    {
        if(view.getId()==R.id.button)
        {System.out.println("button1被按下");
           String name=editText.getText().toString().trim();
            textView.setText(name);}
        else if(view.getId()==R.id.button2)
            System.out.println("button2被按下");
    }
}
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第二种方法：将implements写在监听类上

package com.example.test921;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import androidx.appcompat.app.AppCompatActivity;
public class Activity2 extends AppCompatActivity {
    private TextView textView;
    private EditText editText;
    private Button bnt;
    private Button bnt2;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textView=this.findViewById(R.id.textView);
        editText=this.findViewById(R.id.editText);
        bnt=this.findViewById(R.id.button);
        bnt2=this.findViewById(R.id.button2);
        //两个按钮绑定到一个监听类，两种写法都可以
        Listener listener=new Listener();
        bnt.setOnClickListener(listener);
		 //如果不写Listener listener=new Listener();就直接在括号内new
        bnt2.setOnClickListener(new Listener());
    }

    class Listener implements View.OnClickListener{

        @Override
        public void onClick(View view) {
            if(view.getId()==R.id.button2)
                System.out.println("button2");
            else if (view.getId()==R.id.button) {
                System.out.println("button");
            }
        }
    }
}
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第三种方法：由于新版似乎不允许button根据id用switch语句，所以可以改用textview

public class MainActivity extends AppCompatActivity {
    private TextView input;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        input = this.findViewById(R.id.input);
    }
    public void oneOnClick(View view){
        if(view instanceof TextView){
            String oneText = ((TextView)view).getText().toString();
                switch (oneText){
                    case "+/-":
                        break;
                    case "%":
                        break;
                    case "1":
                        break；
            }
        }
    }
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在对应的布局文件里也需要为textview添加一个属性

<TextView
    android:id="@+id/C"
    android:onClick="oneOnClick"
    android:layout_width="0dp"
    android:layout_weight="1"
    android:layout_height="match_parent"
    android:text="C"
 />
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