转！Android使用BitmapFactory.Options解决加载大图片内存溢出问题

由于Android对图片使用内存有限制，若是加载几兆的大图片便内存溢出。Bitmap会将图片的所有像素（即长x宽）加载到内存中，如果图片分辨率过大，会直接导致内存溢出（java.lang.OutOfMemoryError），只有在BitmapFactory加载图片时使用BitmapFactory.Options对相关参数进行配置来减少加载的像素。
1、设置缩放大小对图片作处理
public Bitmap getBitmapFromFile(File dst, int width, int height) {

if (null != dst && dst.exists()) {

BitmapFactory.Options opts = null;

if (width > 0 && height > 0) {

opts = new BitmapFactory.Options();

opts.inJustDecodeBounds = true;

BitmapFactory.decodeFile(dst.getPath(), opts);

// 计算图片缩放比例

final int minSideLength = Math.min(width, height);

opts.inSampleSize = computeSampleSize(opts, minSideLength,

width * height);

opts.inJustDecodeBounds = false;

opts.inInputShareable = true;

opts.inPurgeable = true;

}

try {

return BitmapFactory.decodeFile(dst.getPath(), opts);

} catch (OutOfMemoryError e) {

e.printStackTrace();

}

}

return null;

}

public static int computeSampleSize(BitmapFactory.Options options,

int minSideLength, int maxNumOfPixels) {

int initialSize = computeInitialSampleSize(options, minSideLength,

maxNumOfPixels);

int roundedSize;

if (initialSize <= 8) {

roundedSize = 1;

while (roundedSize < initialSize) {

roundedSize <<= 1;

}

} else {

roundedSize = (initialSize + 7) / 8 * 8;

}

return roundedSize;

}

private static int computeInitialSampleSize(BitmapFactory.Options options,

int minSideLength, int maxNumOfPixels) {

double w = options.outWidth;

double h = options.outHeight;

int lowerBound = (maxNumOfPixels == -1) ? 1 : (int) Math.ceil(Math

.sqrt(w * h / maxNumOfPixels));

int upperBound = (minSideLength == -1) ? 128 : (int) Math.min(Math

.floor(w / minSideLength), Math.floor(h / minSideLength));

if (upperBound < lowerBound) {

// return the larger one when there is no overlapping zone.

return lowerBound;

}

if ((maxNumOfPixels == -1) && (minSideLength == -1)) {

return 1;

} else if (minSideLength == -1) {

return lowerBound;

} else {

return upperBound;

}

}

转载自: http://orgcent.com/android-outofmemoryerror-load-big-image/ | 萝卜白菜的博客