Android开发入门——响应按键按下和弹起事件以及触摸屏事件

只要实现几个方法即可：

boolean onKeyDown（int keyCode,KeyEvent event) ; //按键按下事件

boolean onKeyUp(int keyCode,KeyEvent event) //按键弹起事件

boolean onTouchEvent(MotionEvent event) //触摸屏事件







package exam.apan;


import android.app.Activity;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.MotionEvent;
import android.widget.Toast;

public class KeyTestActivity extends Activity
{
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}

//按键按下触发的事件
public boolean onKeyDown(int keyCode,KeyEvent event)
{
switch(keyCode)
{
case KeyEvent.KEYCODE_DPAD_CENTER:
DisplayToast("按下：中键");
break;
case KeyEvent.KEYCODE_DPAD_UP:
DisplayToast("按下：上方向键");
break;
case KeyEvent.KEYCODE_DPAD_DOWN:
DisplayToast("按下：下方向键");
break;
case KeyEvent.KEYCODE_DPAD_LEFT:
DisplayToast("按下：左方向键");
break;
case KeyEvent.KEYCODE_DPAD_RIGHT:
DisplayToast("按下：右方向键");

}
return false;
}


//按键弹起触发的事件
public boolean onKeyUp(int keyCode,KeyEvent event)
{
switch(keyCode)
{
case KeyEvent.KEYCODE_DPAD_CENTER:
DisplayToast("弹起：中键");
break;
case KeyEvent.KEYCODE_DPAD_UP:
DisplayToast("弹起：上方向键");
break;
case KeyEvent.KEYCODE_DPAD_DOWN:
DisplayToast("弹起：下方向键");
break;
case KeyEvent.KEYCODE_DPAD_LEFT:
DisplayToast("弹起：左方向键");
break;
case KeyEvent.KEYCODE_DPAD_RIGHT:
DisplayToast("弹起：右方向键");


}
return false;

}


//笔触事件
public boolean onTouchEvent(MotionEvent event)
{
int iAction = event.getAction();
if(iAction == MotionEvent.ACTION_CANCEL ||
iAction == MotionEvent.ACTION_DOWN||
iAction == MotionEvent.ACTION_MOVE)
{
return false;
}

//得到笔触的位置
int x = (int)event.getX();
int y = (int)event.getY();
DisplayToast("笔触的坐标：(" + x + "," + y + ")");

return false;
}

//显示Toast
public void DisplayToast(String string)
{
Toast.makeText(KeyTestActivity.this,string,Toast.LENGTH_SHORT).show();

}
}