Andorid学习之游戏背景腾挪
Andorid学习之游戏背景移动
借助Bitmap和createBitmap方法可以挖取源位图的一块,这样可以在程序中通过定时器不断的挖取源位图中的不同块,给游戏者一种背景在移动,即对象在向前移动的假象。
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 MoveBack extends Activity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(new MyView(this)); } class MyView extends View { // 记录背景位图的实际高度 final int BACK_HEIGHT = 1700; // 背景图片 private Bitmap back; private Bitmap plane; // 背景图片的开始位置 final int WIDTH = 480; final int HEIGHT = 800; private int startY = BACK_HEIGHT - HEIGHT; public MyView(Context context) { super(context); back = BitmapFactory.decodeResource(context.getResources(),R.drawable.back_img); plane = BitmapFactory.decodeResource(context.getResources(),R.drawable.plane); final Handler handler = new Handler() { public void handleMessage(Message msg) { if (msg.what == 0x123) { // 重新开始移动 if (startY <= 0) { startY = BACK_HEIGHT - HEIGHT; } else { startY -= 3; } } invalidate(); } }; new Timer().schedule(new TimerTask() { public void run() { handler.sendEmptyMessage(0x123); } }, 0, 100); } public void onDraw(Canvas canvas) { // 根据原始位图和Matrix创建新图片 Bitmap bitmap2 = Bitmap.createBitmap(back, 0, startY, WIDTH, HEIGHT); // 绘制新位图 canvas.drawBitmap(bitmap2, 0, 0, null); // 绘制飞机 canvas.drawBitmap(plane, 160, 360, null); } } }