Android settings picture Bitmap any transparency

In two ways, the first idea is to get the bitmap pixel value into a int[] array by manipulating the bitmap, because bitmap is usually the ARGB8888 format in Android, so the highest bit is the value of a channel, After the alignment is changed, create a new bitmap. The second idea is to change the transparency of the view by setting the transparency of the canvas's paint and then Canvas.drawbitmap (). The specific code is as follows:

The first way of thinking:

public static Bitmap Gettransparentbitmap (Bitmap sourceimg, int number) {int[] argb = new Int[sourceimg.getwidth () * source Img.getheight ()];sourceimg.getpixels (ARGB, 0, Sourceimg.getwidth (), 0, 0, sourceimg.getwidth (), Sourceimg.getheight ( );//Get the ARGB value of the picture number = # 255/100;for (int i = 0; i < argb.length; i++) {Argb[i] = (# << 24) | (Argb[i] & 0X00FFFFFF);} sourceimg = Bitmap.createbitmap (ARGB, Sourceimg.getwidth (), Sourceimg.getheight (), config.argb_8888); return sourceimg;}

The above code by my pro-test available, fixed the link two errors. The range of number is 0-100,0, which means that it is completely transparent and completely invisible. One of the most critical steps you can see is argb[i] = (number << 24) | (Argb[i] & 0X00FFFFFF); Pass(Argb[i] & 0X00FFFFFF) Set the A-channel of the pixel at point I to 0, and then (num<<24) to do or operate. Shift See links

The second way of thinking:

Example code:

    Class Drawcanvas extends View {public        Drawcanvas (context context) {            super (context);        }         @Override        protected void OnDraw (canvas canvas) {            super.ondraw (canvas);             Get resource picture of Bitmap            Bitmap vbitmap = Bitmapfactory.decoderesource (This.getresources ()                                                         , R.drawable.icon                                                         );             Build Paint Object            paint vpaint = new paint ();            Vpaint. SetStyle (Paint.Style.STROKE);   Hollow            Vpaint. Setalpha ();              Canvas.drawbitmap (Vbitmap, +, +, null);  Non-transparent            canvas.drawbitmap (Vbitmap, vpaint);  Transparent        }    }

About Canvas.drawbitmap See links

Both methods have their uses and which ones are used.