Android Scratch卡片应用

Question

我正在为大学做一个小项目，不知道是否有人能告诉我，我将如何去做一个刮刮卡应用程序。这个应用程序应该有一个图像覆盖另一个。上面的一个应该允许用户根据他们在图像上摩擦的位置来删除图像，因此删除的图像的一部分会暴露出下面的图像。就像刮刮卡一样。任何帮助都是最好的！

这是我目前使用的代码。

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

    LinearLayout l1 = (LinearLayout) findViewById(R.id.LAYOUTTEST1);
    Panel p1 = new Panel(null);
}

    class Panel extends View{

        private Bitmap  mBitmap;
        private Canvas  mCanvas;
        private Path    mPath;
        private Paint   mPaint;
    //  private Paint nPaint;
        Bitmap bitmap;
        Canvas pcanvas ;
        int x = 0;
        int y =0;
        int r =0;
        public Panel(Context context) {
            super(context);

            Log.v("Panel", "STROKE");

            setFocusable(true);
            setBackgroundColor(Color.TRANSPARENT);
        /*  
            WallpaperManager wallpaperManager = WallpaperManager.getInstance(context);
            //WallpaperDrawable wallpaperDrawable=wallpaperManager.getDrawable();
            try {
                wallpaperManager.setBitmap(bmp);
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }*/
            //setBackgroundDrawable(bmp);
            // setting paint 
        /*  nPaint = new Paint();
            nPaint.setStyle(Paint.Style.FILL);*/

            mPaint = new Paint();
            mPaint.setAlpha(0);
            mPaint.setStyle(Paint.Style.FILL_AND_STROKE);
            mPaint.setStrokeCap(Paint.Cap.BUTT);
            mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_IN));//.Mode.DST_IN));
            mPaint.setAntiAlias(false);

            // getting image from resources
            Resources r = this.getContext().getResources();

            Bitmap bm = BitmapFactory.decodeResource(getResources(),  R.drawable.mainscreen_background);
            Bitmap bm1 = BitmapFactory.decodeResource(getResources(),R.drawable.foreground_image);
            // converting image bitmap into mutable bitmap
            bitmap =  bm.createBitmap(bm.getWidth(), bm.getHeight(), Config.ARGB_8888);
            //bitmap = bm1.createBitmap(bm1.getWidth(),bm1.getHeight(),Config.ARGB_8888);
            pcanvas = new Canvas();
            pcanvas.setBitmap(bitmap);                   // drawXY will result on that Bitmap
            pcanvas.drawBitmap(bm, 0, 0, null);
            pcanvas.drawBitmap(bm1,0,0,null);


        }

        @Override
        protected void onDraw(Canvas canvas) {


            Rect cBK = new Rect();
            //canvas.set
            cBK.set(0,0,canvas.getWidth(),canvas.getHeight());

            //pcanvas.drawRect(cBK, nPaint);
            // draw a circle that is  erasing bitmap            
            pcanvas.drawCircle(x, y, r, mPaint);
            //pcanvas.drawLine(x, y, 0, 0, mPaint);

            canvas.drawBitmap(bitmap, 0, 0,null);

            super.onDraw(canvas);

        }



        @Override
        public boolean onTouchEvent(MotionEvent event) {

            // set paramete to draw circle on touch event
            x = (int) event.getX();
            y = (int) event.getY();

            r =20;
            // Atlast invalidate canvas
            invalidate();
            return true;
        }
    }
}

现在，正如你在上面看到的，有很多关于我们尝试过的东西的评论。理想情况下，我希望能够创建一个Panel类的实例，将workinggraphics类contextview设置为XML LinearLayout (或者使用SurfaceView w/e，我不太清楚)，然后在定义的LinearLayout上设置一个背景图像，当画布擦除我们设置的位图图像时显示出来。

无论如何，任何建议都会被采纳，非常感谢！

Answer 1

我创建了一个名为WScrarchView的库，在这个库中，您可以在布局xml中实现只有几行的临时视图。希望这能帮助那些仍然在寻找解决方案https://github.com/winsontan520/Android-WScratchView的人