android 三种点击事件

button_id=(Button)findViewById(R.id.button_id);

button_id.setOnClickListener(new MyListener());

class MyListener implements OnClickListener
{
@Override
public void onClick(View v)
{
System.out.println("这是一个提示！");
} 
}

button_id.setOnClickListener(this);

public class MainActivity extends Activity implements  OnClickListener{  实现接口

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
System.out.println("wangji");
}

button_id.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
System.out.println("");
Log.e("定义","字段");
}
});