Android 画布擦除位图代码
我正在使用下面的代码在触摸事件中从画布上擦除位图 它在android 2.3中运行良好,但在4.0中,它显示的是黑点,而不是删除位图 任何人都可以帮忙 公共类Demouch扩展活动{Android 画布擦除位图代码,android,canvas,bitmap,Android,Canvas,Bitmap,我正在使用下面的代码在触摸事件中从画布上擦除位图 它在android 2.3中运行良好,但在4.0中,它显示的是黑点,而不是删除位图 任何人都可以帮忙 公共类Demouch扩展活动{ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(new TouchView(this)); } class TouchVi
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(new TouchView(this));
}
class TouchView extends View {
Bitmap bgr;
Bitmap overlayDefault;
Bitmap overlay;
Paint pTouch;
int X = -100;
int Y = -100;
Canvas c2;
public TouchView(Context context) {
super(context);
bgr = BitmapFactory.decodeResource(getResources(), R.drawable.a1);
overlayDefault = BitmapFactory.decodeResource(getResources(),
R.drawable.a2);
overlay = BitmapFactory.decodeResource(getResources(),
R.drawable.a2).copy(Config.ARGB_4444, true);
c2 = new Canvas(overlay);
pTouch = new Paint(Paint.ANTI_ALIAS_FLAG);
pTouch.setXfermode(new PorterDuffXfermode(Mode.CLEAR));
pTouch.setColor(Color.TRANSPARENT);
pTouch.setMaskFilter(new BlurMaskFilter(15, Blur.NORMAL));
pTouch.setAntiAlias(true);
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN: {
X = (int) ev.getX();
Y = (int) ev.getY();
invalidate();
break;
}
case MotionEvent.ACTION_MOVE: {
X = (int) ev.getX();
Y = (int) ev.getY();
invalidate();
break;
}
case MotionEvent.ACTION_UP:
break;
}
return true;
}
@Override
public void onDraw(Canvas canvas) {
super.onDraw(canvas);
// draw background
canvas.drawBitmap(bgr, 0, 0, null);
// copy the default overlay into temporary overlay and punch a hole
// in it
// c2.drawBitmap(overlayDefault, 0, 0, null); // exclude this line
// to
// show all as you draw
c2.drawCircle(X, Y, 20, pTouch);
// draw the overlay over the background
canvas.drawBitmap(overlay, 0, 0, null);
}
}
}看看我的这种方法。视图
EditImageView
是一个自定义的ImageView
,我也对其应用了擦除功能。我也有同样的问题,直到我在if语句中应用了下面的代码。这解决了3.0及更高版本的问题
/**
* Sets the image to the view in the content view
* @param view
*/
private void setImageView(EditImageView view) {
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
view.setLayoutParams(params);
// #### THIS IS THE IMPORTANT PART ######
if (Build.VERSION.SDK_INT >= 11) {
view.setLayerType(View.LAYER_TYPE_SOFTWARE, null);
}
LinearLayout main = (LinearLayout) findViewById(R.id.galleryImage);
main.removeAllViews();
main.addView(view);
}
编辑
您可能可以在代码中执行类似的操作
public TouchView(Context context) {
super(context);
// This should fix it from 3.0 and up
if (Build.VERSION.SDK_INT >= 11) {
setLayerType(View.LAYER_TYPE_SOFTWARE, null);
}
bgr = BitmapFactory.decodeResource(getResources(), R.drawable.a1);
overlayDefault = BitmapFactory.decodeResource(getResources(),
R.drawable.a2);
overlay = BitmapFactory.decodeResource(getResources(),
R.drawable.a2).copy(Config.ARGB_4444, true);
c2 = new Canvas(overlay);
pTouch = new Paint(Paint.ANTI_ALIAS_FLAG);
pTouch.setXfermode(new PorterDuffXfermode(Mode.CLEAR));
pTouch.setColor(Color.TRANSPARENT);
pTouch.setMaskFilter(new BlurMaskFilter(15, Blur.NORMAL));
pTouch.setAntiAlias(true);
}
希望这也能帮助你/############if(Build.VERSION.SDK_INT>=11){view.setLayerType(view.LAYER(TYPE)SOFTWARE,null)}添加这行后,它会显示一个白点。你的视图后面是什么?如果它后面没有任何东西,它就不会显示任何东西。后面有另一张图片。谢谢!工作起来很有魅力。只要看看下面的代码,下面的代码就会对你有用