Android自定义View之刮刮卡效果

Android自定义View之刮刮卡效果

@SuppressLint("DrawAllocation")
public class GGCard extends View {
/**
* @param mPaint
*           擦除前景色的画笔
*/
PaintmPaint;
/**
* @param mCanvas
*           用于绘制刮刮卡的前景色（bitmap）
*
*/
CanvasmCanvas;
/**
*记录Touch事件中相对与View本身的上次坐标
*/
intmX, mY;
/**
* @param mPath
*           保存画笔路径
*/
PathmPath;
/**
* @param ForegroundBitmap
*           刮刮卡的前景色
* @param BackgroundBitmap
*           刮刮卡的背景色
*/
BitmapForegroundBitmap, BackgroundBitmap;

publicGGCard(Context context, AttributeSet attrs) {
super(context,attrs);
mPaint= new Paint();
mPath= new Path();
mPaint.setAntiAlias(true);
mPaint.setDither(true);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeJoin(Paint.Join.ROUND);//圆角
mPaint.setStrokeCap(Paint.Cap.ROUND);//圆角
mPaint.setColor(Color.RED);
mPaint.setStrokeWidth(10);
}

publicvoid setPaintStrokeWidth(int strokeWidth) {
mPaint.setStrokeWidth(strokeWidth);
}

publicvoid setBackgroundPicture(Bitmap bitmap) {
BackgroundBitmap= bitmap;
}

@Override
protectedvoid onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec,heightMeasureSpec);
ForegroundBitmap= Bitmap.createBitmap(getMeasuredWidth(),
getMeasuredHeight(),Config.ARGB_8888);
mCanvas= new Canvas(ForegroundBitmap);
mCanvas.drawColor(Color.parseColor("#e3e3e3"));
}

@Override
protectedvoid onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawBitmap(ForegroundBitmap, 0,0, null);
if(BackgroundBitmap != null) {
canvas.drawBitmap(BackgroundBitmap,
(getWidth()- BackgroundBitmap.getWidth()) / 2,
(getHeight()- BackgroundBitmap.getHeight()) / 2, null);
}
mPaint.setXfermode(newPorterDuffXfermode(PorterDuff.Mode.DST_OUT));
mCanvas.drawPath(mPath,mPaint);
canvas.drawBitmap(ForegroundBitmap,0, 0, null);
}

@SuppressLint("ClickableViewAccessibility")
@Override
publicboolean onTouchEvent(MotionEvent event) {
intnX = (int) event.getX();
intnY = (int) event.getY();
switch(event.getAction()) {
caseMotionEvent.ACTION_DOWN:
mX= nX;
mY= nY;
mPath.moveTo(mX,mY);
break;
caseMotionEvent.ACTION_MOVE:
mPath.lineTo(nX,nY);
mX= nX;
mY= nY;
break;
caseMotionEvent.ACTION_UP:
break;
}
invalidate();
returntrue;
}

}

<com.sun.view.GGCard
android:layout_width="match_parent"
android:layout_height="180dp"
android:id="@+id/ggCard"
/>

GGCard ggCard=(GGCard) findViewById(R.id.ggCard);
ggCard.setBackgroundPicture(BitmapFactory.decodeResource(getResources(),R.drawable.ic_launcher));
ggCard.setPaintStrokeWidth(20);