由於Android對圖片使用記憶體有限制，若是載入幾兆的大圖片便記憶體溢位。Bitmap會將圖片的所有畫素（即長x寬）載入到記憶體中，如果圖片解析度過大，會直接導致記憶體溢位（java.lang.OutOfMemoryError），只有在BitmapFactory載入圖片時使用BitmapFactory.Options對相關引數進行配置來減少載入的畫素。

1、設定縮放大小對圖片作處理

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);
            // 計算圖片縮放比例
            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;
    }
}
 

	/**
	 * 獲取經過處理的資源圖，包括普通圖和.9圖
	 * @param context 應用環境
	 * @param id 資源id
	 * @return Drawable格式的資源
	 * <p>
	 * 以1080p為基準，小於此尺寸的縮寫，大於此尺寸的放大
	 */
	public static Drawable getCompatibleDrawable(Context context, int id) {
		BitmapFactory.Options options = new BitmapFactory.Options();
		options.inDensity = 240;
		options.inScreenDensity = (int) (240*ratio);
		options.inTargetDensity = (int) (240*ratio);

		Bitmap bitmap = BitmapFactory.decodeResource(context.getResources(),
				id, options);
		byte[] ninePathChunk = bitmap.getNinePatchChunk();
		
		if (NinePatch.isNinePatchChunk(ninePathChunk)) {
			NinePatch ninePath = new NinePatch(bitmap, ninePathChunk, null);
			
			return new NinePatchDrawable(ninePath);
		} else {
			return new BitmapDrawable(bitmap);
		}
	}