android 布局背景模糊化处理

在模仿 IOS 密码输入页面的时候发现其背景有模糊处理,于是了解了一下并记录下来,以便使用.在Android 中具体实现方法如下

查考 http://www.cnblogs.com/lipeil/p/3997992.html

 private void applyBlur() {

     // 获取壁纸管理器
     WallpaperManager wallpaperManager = WallpaperManager.getInstance(this.getContext());
     // 获取当前壁纸
     Drawable wallpaperDrawable = wallpaperManager.getDrawable();
     // 将Drawable,转成Bitmap
     Bitmap bmp = ((BitmapDrawable) wallpaperDrawable).getBitmap();

     blur(bmp);
 }

 

下面之所以要进行small 和big的处理,是因为仅仅靠ScriptIntrinsicBlur  来处理模式,不能到达更模式的效果,如果需要加深模式效果就需要先把背景图片缩小,在处理完之后再放大.这个可以使用Matrix 来实现,而且这样可以缩短模糊化得时间

 @TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR1)
 private void blur(Bitmap bkg) {
     long startMs = System.currentTimeMillis();
     float radius = 20;

     bkg = small(bkg);
     Bitmap bitmap = bkg.copy(bkg.getConfig(), true);

     final RenderScript rs = RenderScript.create(this.getContext());
     final Allocation input = Allocation.createFromBitmap(rs, bkg, Allocation.MipmapControl.MIPMAP_NONE,
             Allocation.USAGE_SCRIPT);
     final Allocation output = Allocation.createTyped(rs, input.getType());
     final ScriptIntrinsicBlur script = ScriptIntrinsicBlur.create(rs, Element.U8_4(rs));
     script.setRadius(radius);
     script.setInput(input);
     script.forEach(output);
     output.copyTo(bitmap);

     bitmap = big(bitmap);
     setBackground(new BitmapDrawable(getResources(), bitmap));
     rs.destroy();
     Log.d("zhangle","blur take away:" + (System.currentTimeMillis() - startMs )+ "ms");
 }

 private static Bitmap big(Bitmap bitmap) {
       Matrix matrix = new Matrix();
       matrix.postScale(4f,4f); //长和宽放大缩小的比例
       Bitmap resizeBmp = Bitmap.createBitmap(bitmap,0,0,bitmap.getWidth(),bitmap.getHeight(),matrix,true);
       return resizeBmp;
  }

  private static Bitmap small(Bitmap bitmap) {
       Matrix matrix = new Matrix();
       matrix.postScale(0.25f,0.25f); //长和宽放大缩小的比例
       Bitmap resizeBmp = Bitmap.createBitmap(bitmap,0,0,bitmap.getWidth(),bitmap.getHeight(),matrix,true);
       return resizeBmp;
 }