public void demo(View view){
      Toast.makeText(MainActivity.this, "第二个按钮被点击了",Toast.LENGTH_SHORT).show();
  }

button = (Button)findViewById(R.id.button1);
    button.setOnClickListener(new OnClickListener() {  

      @Override
      public void onClick(View view) {

          Toast.makeText(MainActivity.this, "通过匿名内部类：第一个按钮被点击了",Toast.LENGTH_SHORT).show();
          
      }
    });

button=(Button)findViewById(R.id.button2)

package com.mqz.android_event_test;

import android.content.Context;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Toast;

public class BtnTest implements OnClickListener {

  private Context context;
  public BtnTest(Context context){
    this.context=context;
  }
  
  @Override
  public void onClick(View view) {
    
      Toast.makeText(context, "通过外部类实现OnClickListener接口：第一个按钮被点击了",Toast.LENGTH_SHORT).show();
    
    
  }


}

button.setOnClickListener(new BtnTest(this))

package com.mqz.android_event_test;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;


public class MainActivity extends Activity implements OnClickListener{


  private Button button;


  @Override
  public void onClick(View view) {


      Toast.makeText(MainActivity.this, "通过MainActivity实现OnClickListener接口：第一个按钮被点击了",Toast.LENGTH_SHORT).show();
    
  }
  
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    button = (Button)findViewById(R.id.button2);
    button.setOnClickListener(this);
    
  }
  
}

button=(Button)findViewById(R.id.button2)

class BtnTest1 implements OnClickListener{  
    @Override
    public void onClick(View view) {
     
        Toast.makeText(MainActivity.this, "通过成员内部类：第二个按钮被点击了",Toast.LENGTH_SHORT).show();
      
    }
    
  }