从文件加载图像时出现 OutOfMemoryError

Question

我知道这个question，据我所知，我实际上正在做与最佳答案建议相同的事情。但是我仍然在内存较少的设备上遇到 outOfMemory 崩溃。

编辑：我只是用手机的原生相机拍照。没什么好看的。

private Bitmap setImgViewFromFile(ImageView imgView, String file) {
    // Get the dimensions of the View
    int targetW = Math.max(imgView.getWidth(), 600);
    int targetH = Math.max(imgView.getHeight(), 800);


    // Get the dimensions of the bitmap
    BitmapFactory.Options bmOptions = new BitmapFactory.Options();
    bmOptions.inJustDecodeBounds = true;
    BitmapFactory.decodeFile(file, bmOptions);
    int photoW = bmOptions.outWidth;
    int photoH = bmOptions.outHeight;

    // Determine how much to scale down the image
    int scaleFactor = Math.min(photoW / targetW, photoH / targetH);

    // Decode the image file into a Bitmap sized to fill the View
    bmOptions.inJustDecodeBounds = false;
    bmOptions.inSampleSize = scaleFactor;
    bmOptions.inPurgeable = true;

    Bitmap bitmap = BitmapFactory.decodeFile(file, bmOptions);
    imgView.setImageBitmap(bitmap);
    return bitmap;
}

堆栈跟踪：

12-10 10:38:04.120    4144-4144/com.loop E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.loop, PID: 4144
java.lang.OutOfMemoryError
        at android.graphics.BitmapFactory.nativeDecodeStream(Native Method)
        at android.graphics.BitmapFactory.decodeStreamInternal(BitmapFactory.java:613)
        at android.graphics.BitmapFactory.decodeStream(BitmapFactory.java:589)
        at android.graphics.BitmapFactory.decodeFile(BitmapFactory.java:369)

谁能看出我做错了什么？

Answer 1

改变：

// Determine how much to scale down the image
int scaleFactor = Math.min(photoW / targetW, photoH / targetH);

到

// Determine how much to scale down the image
int scaleFactor = findBestSampleSize(photoW , photoH ,targetW,targetH);

findBestSampleSize 是：

/**
 * Returns the largest power-of-two divisor for use in downscaling a bitmap
 * that will not result in the scaling past the desired dimensions.
 *
 * @param actualWidth Actual width of the bitmap
 * @param actualHeight Actual height of the bitmap
 * @param desiredWidth Desired width of the bitmap
 * @param desiredHeight Desired height of the bitmap
 */
// Visible for testing.
static int findBestSampleSize(
        int actualWidth, int actualHeight, int desiredWidth, int desiredHeight) {
    double wr = (double) actualWidth / desiredWidth;
    double hr = (double) actualHeight / desiredHeight;
    double ratio = Math.min(wr, hr);
    float n = 1.0f;
    while ((n * 2) <= ratio) {
        n *= 2;
    }

    return (int) n;
}

如果仍然得到OOM，请将float n = 1.0f; 更改为float n = 2.0f; 或float n = 4.0f; 或...