Android开发：ImageView影子和图层效果

Android开发：ImageView阴影和图层效果

Android开发：ImageView阴影和图层效果：

1. import?Android.app.Activity;??import?Android.content.Context;??
2. import?Android.graphics.Bitmap;??import?Android.graphics.BitmapFactory;??
3. import?Android.graphics.Canvas;??import?Android.graphics.Color;??
4. import?Android.graphics.Paint;??import?Android.graphics.PorterDuff;??
5. import?Android.graphics.PorterDuff.Mode;??import?Android.graphics.PorterDuffXfermode;??
6. import?Android.graphics.Rect;??import?Android.graphics.RectF;??
7. import?Android.graphics.drawable.Drawable;??import?Android.os.Bundle;??
8. import?Android.view.View;????
9. public?class?MyCanvasActivity?extends?Activity?{??????/**?Called?when?the?activity?is?first?created.?*/??
10. ????@Override??????public?void?onCreate(Bundle?savedInstanceState)?{??
11. ????????super.onCreate(savedInstanceState);??????????setContentView(new?ImageEffect(this));??
12. ????}????????
13. ??class?ImageEffect?extends?View{????????Paint?paint;??
14. ?????public?ImageEffect(Context?context){???????????super(context);??
15. ?????????paint=?new?Paint();?//初始化画笔，为后面阴影效果使用。????????????paint.setAntiAlias(true);//去除锯齿。???
16. ?????????paint.setShadowLayer(5f,?5.0f,?5.0f,?Color.BLACK);?//设置阴影层，这是关键。????????????paint.setXfermode(new?PorterDuffXfermode(Mode.SRC_IN));??
17. ????????????????}??
18. ?????public?void?onDraw(Canvas?canvas){???????????super.onDraw(canvas);??
19. ?????????int?posX??=?20;???????????int?posY?=?50;??
20. ?????????int?PicWidth,PicHeight;?????????????
21. ????????Drawable?drawable?=?getResources().getDrawable(R.drawable.pic);??????????Drawable?dbe????=?getResources().getDrawable(R.drawable.pic).mutate();//如果不调用mutate方法，则原图也会被改变，因为调用的资源是同一个，所有对象是共享状态的。???
22. ????????Drawable?drawTest?=?getResources().getDrawable(R.drawable.pic);??????????Bitmap?bmp?=?BitmapFactory.decodeResource(getResources(),?R.drawable.pic);??
23. ????????PicWidth?=?drawable.getIntrinsicWidth();??????????PicHeight?=?drawable.getIntrinsicHeight();??
24. ??????????????????drawTest.setBounds(posX,?(2?*?posY)?+?PicHeight,?posX?+?PicWidth,?(2?*?posY)?+?2?*?PicHeight?);??
25. ????????drawable.setBounds(posX,posY,posX+PicWidth,posY+PicHeight);??????????dbe.setBounds(0,?0,?PicWidth,?PicHeight);??
26. ??????????????????canvas.drawColor(Color.WHITE);//设置画布颜色???
27. ????????canvas.save(Canvas.MATRIX_SAVE_FLAG);??????????dbe.setColorFilter(0x7f000000,PorterDuff.Mode.SRC_IN);??
28. ????????canvas.translate(posX?+?(int)(0.9?*?PicWidth/2),?posY?+?PicHeight/2);//图像平移为了刚好在原图后形成影子效果。???????????canvas.skew(-0.9F,?0.0F);//图像倾斜效果。???
29. ????????canvas.scale(1.0f,?0.5f);//图像（其实是画布）缩放，Y方向缩小为1/2。???????????dbe.draw(canvas);//此处为画原图像影子效果图，比原图先画，则会在下层。???
30. ????????drawable.clearColorFilter();??????????canvas.restore();??
31. ?????????????????canvas.save(Canvas.MATRIX_SAVE_FLAG);??
32. ????????drawable.draw(canvas);//此处为画原图像，由于canvas有层次效果，因此会盖在影子之上。???????????canvas.restore();??
33. ??????????????????//默认无效果原图???
34. ????????canvas.save(Canvas.MATRIX_SAVE_FLAG);??????????drawTest.draw(canvas);??
35. ????????canvas.restore();????????????
36. ????????//图片阴影效果???????????Rect?rect?=?new?Rect(2*posX?+?PicWidth?+?3,?2*posY?+?PicHeight?+?3,?2*posX?+?2*PicWidth?-?2,?2*posY?+?2*PicHeight?-?2);??
37. ????????//由于图片的实际尺寸比显示出来的图像要大一些，因此需要适当更改下大小，以达到较好的效果?????????????
38. ????????RectF?rectF?=?new?RectF(rect);??????????canvas.drawRoundRect(rectF,?10f,?10f,?paint);//在原有矩形基础上，画成圆角矩形，同时带有阴影层。???
39. ????????canvas.drawBitmap(bmp,?2*posX?+?PicWidth,?2*posY?+?PicHeight,?null);//画上原图。???????????canvas.restore();??
40. ????????}????}??
41. } ?