android bitmap oom

 

public static int calculateInSampleSize(BitmapFactory.Options options,

int reqWidth, int reqHeight) {

// Raw height and width of image

final int height = options.outHeight;

final int width = options.outWidth;

int inSampleSize = 1;

if (height > reqHeight || width > reqWidth) {

// Calculate ratios of height and width to requested height and

// width

final int heightRatio = Math.round((float) height

/ (float) reqHeight);

final int widthRatio = Math.round((float) width / (float) reqWidth);

// Choose the smallest ratio as inSampleSize value, this will

// guarantee

// a final image with both dimensions larger than or equal to the

// requested height and width.

inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio;

}

return inSampleSize;

}

 

public static Bitmap decodeSampledBitmapFromResource(Resources res,

int resId, int reqWidth, int reqHeight) {

// First decode with inJustDecodeBounds=true to check dimensions

final BitmapFactory.Options options = new BitmapFactory.Options();

options.inJustDecodeBounds = true; //当设置inJustDecodeBounds为true时map为null设置了options高度，宽度和图片类型

BitmapFactory.decodeResource(res, resId, options);

// Calculate inSampleSize

options.inSampleSize = calculateInSampleSize(options, reqWidth,

reqHeight);//获取图片本来大小宽高的1/inSampleSize像素的1/(inSmapleSize*inSampleSize)

// Decode bitmap with inSampleSize set

options.inJustDecodeBounds = false;

return BitmapFactory.decodeResource(res, resId, options);

}