<Button
    android:id="@+id/button1"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_below="@+id/textView1"
    android:layout_marginTop="20dp"
    android:text="方法一：匿名内部类" />

public class MainActivity extends Activity{
  
  private Button btn1;
  
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    
    /*
     * 方法一：使用匿名内部类实现button按钮的
     */
    //绑定button按钮
    btn1 = (Button) findViewById(R.id.button1);
    
    //监听button事件
    btn1.setOnClickListener(new OnClickListener() {
      @Override
      public void onClick(View v) {
        Toast tot = Toast.makeText(
            MainActivity.this,
            "匿名内部类实现button点击事件",
            Toast.LENGTH_LONG);
        tot.show();
      }
    });
  }
}

<Button
    android:id="@+id/button2"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_alignRight="@+id/button1"
    android:layout_below="@+id/button1"
    android:layout_marginTop="20dp"
    android:text="方法二：独立类" />

public class MainActivity extends Activity {
  
  private Button btn2;

  
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    
    /*
     * 方法二：独立类实现button实现
     */
    btn2 = (Button) findViewById(R.id.button2);
    btn2.setOnClickListener(new btn2Click(this));
    
    
  }
}

public class btn2Click implements OnClickListener {

  private Context context;
  
  //重载btn2Click方法
  public btn2Click(Context ct){
    this.context=ct;
  }
  
  @Override
  public void onClick(View v) {
    Toast tot = Toast.makeText(
        context,
        "独立类实现button点击事件",
        Toast.LENGTH_LONG);
    tot.show();  
  }

}

<Button
    android:id="@+id/button3"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_alignRight="@+id/button2"
    android:layout_below="@+id/button2"
    android:layout_marginTop="20dp"
    android:text="方法三：实现接口" />

public class MainActivity extends Activity implements OnClickListener {

  private Button btn3;
  
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    
    /*
     * 方法三：实现OnClickListener接口
     */
    btn3 = (Button) findViewById(R.id.button3);
    btn3.setOnClickListener(this);
    
  }

  //实现OnClickListener接口中的方法
  @Override
  public void onClick(View v) {
    Toast tot = Toast.makeText(
        MainActivity.this,
        "接口OnClickListener实现button点击事件",
        Toast.LENGTH_LONG);
    tot.show();
    
  }
}

<Button
    android:id="@+id/button4"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_alignLeft="@+id/button3"
    android:layout_below="@+id/button3"
    android:layout_marginTop="20dp"
    android:onClick="btn4Click"
    android:text="方法四：添加xml属性" />

/*
   * 方法四：添加XML属性
   */
  public void btn4Click(View v){
    Toast tot = Toast.makeText(
        MainActivity.this,
        "添加XML标签实现button点击事件",
        Toast.LENGTH_LONG);
    tot.show();
  }