德code文件从SD卡的Andr​​oid以避免内存不足的错误，由于大的位图或setImageURI [英] Decode File From SdCard android to avoid out of memory error due to large bitmap or setImageURI

问题描述

避免outof内存错误从SD卡或从资源选择大的图像文件。 我怎样才能解决这个问题呢？

Avoid outof memory error for selecting large image file from sdcard or from resource. how can i tackle with this problem?

推荐答案

要避免错误，而从SD卡中选择文件中的位图或使用setImageURI到SD卡使用下面的方法：

To avoid error while selecting file from sd card in bitmap or using setImageURI to sdcard use following method:

public static Bitmap decodeScaledBitmapFromSdCard(String filePath,
        int reqWidth, int reqHeight) {

    // First decode with inJustDecodeBounds=true to check dimensions
    final BitmapFactory.Options options = new BitmapFactory.Options();
    options.inJustDecodeBounds = true;
    BitmapFactory.decodeFile(filePath, options);

    // Calculate inSampleSize
    options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);

    // Decode bitmap with inSampleSize set
    options.inJustDecodeBounds = false;
    return BitmapFactory.decodeFile(filePath, options);
}

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;
}

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