Android开发之事件和事件监听器

写了一个打飞机的小程序，用于作为事件监听的学习，此程序须要有实体按键的手机才干运行。

PlaneView.java:

public class PlaneView extends View{

public float currentX;

public float currentY;

Bitmap plane;

public PlaneView(Context context) {

super(context);

// TODO Auto-generated constructor stub

//定义飞机图片

plane = BitmapFactory.decodeResource(context.getResources(), R.drawable.feiji);

setFocusable(true);

}

public void onDraw(Canvas canvas)

{

super.onDraw(canvas);

Paint p = new Paint();

canvas.drawBitmap(plane, currentX, currentY, p);

}

}

Activity.java

public class MainActivity extends Activity {

//定义飞机移动速度

private int speed = 12;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

requestWindowFeature(Window.FEATURE_NO_TITLE);

getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);

final PlaneView planeView = new PlaneView(this);

setContentView(planeView);

//planeView.setBackgroundResource(R.drawable.feiji);

WindowManager win = getWindowManager();

Display dis = win.getDefaultDisplay();

int width = dis.getWidth();

int height = dis.getHeight();

//设置飞机的初始位置

planeView.currentX = width / 2;

planeView.currentY = height - 40;

//为draw组建键盘事件绑定监听器

planeView.setOnKeyListener(new OnKeyListener() {

@Override

public boolean onKey(View source, int keyCode, KeyEvent event) {

// TODO Auto-generated method stub

//获取由哪个键出发的时间

switch(event.getKeyCode())

{

case KeyEvent.KEYCODE_DPAD_DOWN:

planeView.currentY += speed;

break;

case KeyEvent.KEYCODE_DPAD_UP:

planeView.currentY -= speed;

break;

case KeyEvent.KEYCODE_DPAD_LEFT:

planeView.currentX -= speed;

break;

case KeyEvent.KEYCODE_DPAD_RIGHT:

planeView.currentX += speed;

break;

}

//通知planeView组建重绘

planeView.invalidate();

return true;

}

});

}

}

个人辛勤劳动成果。如有转载，请注明出处，谢谢。