Android安卓经典设计例程源代码-MoveBackgroundSample.rar

package tjuci.edu.dl; import java.util.Timer; import java.util.TimerTask; import android.app.Activity; import android.content.Context; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.os.Bundle; import android.os.Handler; import android.os.Message; import android.view.View; public class MoveBackgroundSampleActivity extends Activity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(new MyView(this)); } class MyView extends View{ Bitmap b ; //记录背景位图的实际高度 int back_height ; //图片开始的位置 int width; final int height = 20; private int startY = back_height - height ; public MyView(Context context) { super(context); b = BitmapFactory.decodeResource(context.getResources(), R.drawable.q10); back_height = b.getHeight(); width = b.getWidth(); final Handler h = new Handler(){ @Override public void handleMessage(Message msg) { if(msg.what == 0x123){ if(startY <= 3){ startY = back_height - height; }else{ startY -= 3; } } invalidate(); } }; new Timer().schedule(new TimerTask() { @Override public void run() { // TODO Auto-generated method stub h.sendEmptyMessage(0x123); } }, 0,100); } @Override protected void onDraw(Canvas canvas) { Bitmap b2 = Bitmap.createBitmap(b, 0, startY, width, height); canvas.drawBitmap(b2, 0, 0, null); } } }