java - Load big Images in Android -


it known android has issues storing bitmap data in ram memory. need load image (a photo 13mpx camera) on view , need able zoom-in , zoom-out image. image should mutable. implemented way:

bitmapfactory.options options =  new bitmapfactory.options(); options.inmutable = true; _bitmap = bitmapfactory.decodefile(_path, options);

when take large photo (13 or 8 mpx) programm crushed "out of memory" error. need solution problem. need class can load , operate (scaling it) big images. it's needed equal or less api-8.

i tried universall image loader, has no scaling option. know ideas how solve problem?

a bitmap takes 4 bytes per pixel ==> 13mp equals 52mb of memory. should use bitmapfactory.options size first. using injustdecodebounds bitmap object meta data, without actual image.

bitmapfactory.options options = new bitmapfactory.options(); options.injustdecodebounds = true; bitmapfactory.decoderesource(getresources(), r.id.myimage, options); int imageheight = options.outheight; int imagewidth = options.outwidth;

then calculate scale size screen needs:

public static int calculateinsamplesize(         bitmapfactory.options options, int reqwidth, int reqheight) { // raw height , width of image final int height = options.outheight; final int width = options.outwidth; int insamplesize = 1;  if (height > reqheight || width > reqwidth) {      final int halfheight = height / 2;     final int halfwidth = width / 2;      // calculate largest insamplesize value power of 2 , keeps both     // height , width larger requested height , width.     while ((halfheight / insamplesize) > reqheight             && (halfwidth / insamplesize) > reqwidth) {         insamplesize *= 2;     } }  return insamplesize; }

and use load scaled version of bitmap:

public static bitmap decodesampledbitmapfromresource(resources res, int resid,         int reqwidth, int reqheight) {      // first decode injustdecodebounds=true check dimensions     final bitmapfactory.options options = new bitmapfactory.options();     options.injustdecodebounds = true;     bitmapfactory.decoderesource(res, resid, options);      // calculate insamplesize     options.insamplesize = calculateinsamplesize(options, reqwidth, reqheight);      // decode bitmap insamplesize set     options.injustdecodebounds = false;     return bitmapfactory.decoderesource(res, resid, options); }

this explained in developer guide


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