安卓课程十五 Button按钮的焦点变化

监听单击事件，键盘事件，焦点变换事件和触碰事件。
import android.os.Bundle;
import android.app.Activity;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.View.OnFocusChangeListener;
import android.view.View.OnKeyListener;
import android.view.View.OnTouchListener;
import android.widget.Button;

public class MainActivity extends Activity  implements OnClickListener,OnFocusChangeListener,OnKeyListener,OnTouchListener{

	private Button btn1;
	private Button btn2;
	
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		btn1 = (Button) findViewById(R.id.btn1);
		btn2 = (Button) findViewById(R.id.btn2);
		
		btn1.setOnClickListener(this);
		btn1.setOnFocusChangeListener(this);
		btn1.setOnKeyListener(this) ;
		
		btn2.setOnClickListener(this);
		btn2.setOnFocusChangeListener(this);
		btn2.setOnKeyListener(this) ;
		
	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		getMenuInflater().inflate(R.menu.main, menu);
		return true;
	}

	@Override
	public boolean onKey(View v, int keyCode, KeyEvent event) {
		if(KeyEvent.ACTION_DOWN == event.getAction()){
			System.out.println("键盘按下了");
			
		}
		return false;
	}

	@Override
	public void onFocusChange(View v, boolean hasFocus) {
		// TODO Auto-generated method stub
		Button btn = (Button)v;
		if(hasFocus){
			btn.setBackgroundColor(RESULT_OK);
		}else {
			btn.setBackgroundColor(BIND_ABOVE_CLIENT);
		}
		
	}

	@Override
	public void onClick(View v) {
		 Button btn = (Button)v;
		 
		 int  width = btn.getWidth();
		// int windowWidth = getWindowManager().getDefaultDisplay().getSize(null);
		 System.out.println(width);
		
	}

	@Override
	public boolean onTouch(View v, MotionEvent event) {
	 
		if(MotionEvent.ACTION_UP == event.getAction()){
			
		}
		return false;
	}

}

监听单击事件，键盘事件，焦点变换事件和触碰事件。