java - 大图像的 Android OutOfMemoryError

Question

对于尺寸较大的图像(不是分辨率)，该方法会抛出 OutOfMemoryError我有 12 张 MP 照片，它们的大小各不相同(1.5MB、2.5MB、3.2MB、4.1MB)等，它们的分辨率都是相同的 4000 x 3000(像素)。

resizer 方法适用于大小小于 3MB 的图像，但对于那些大于 3MB 的图像，它会抛出 OutOfMemoryError 我不知道有什么可以解决它，我的应用程序主要用于调整大图像的大小，这真的让我着迷无处可去。

resizer方法是:

public File resizeBitmap(String imPath, int reqSize) {
    File fl = null;
    try{

    // First decode with inJustDecodeBounds=true to check dimensions

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

    BitmapFactory.decodeFile(imPath, options);

    // Calculate inSampleSize

    options.inSampleSize = calculateInSampleSize(options, reqSize);

    // Decode bitmap with inSampleSize set

    options.inJustDecodeBounds = false;
    Bitmap saveImg = BitmapFactory.decodeFile(imPath, options);

    //save resized image
    String tmpName = "IMG_"+String.valueOf(System.currentTimeMillis()) + ".jpg";
    fl = fileCache.getRawFile(tmpName);
    FileOutputStream fos = new FileOutputStream(fl);
    saveImg.compress(Bitmap.CompressFormat.JPEG, 95, fos);
    saveImg.recycle();


    return fl;
}
catch (Throwable eex){
    eex.printStackTrace();
    if(eex instanceof OutOfMemoryError) {
        runOnUiThread(new Runnable() {
            public void run() {
                Toast.makeText(Resizer.this, "Memory ran out", Toast.LENGTH_SHORT).show();
            }
        });
    }
    return null;
 }
}
//Method for calculating insamplesize
public int calculateInSampleSize(BitmapFactory.Options options, int reqSize) {
// Raw height and width of image
final int height = options.outHeight;
final int width = options.outWidth;
Log.i("width",""+width);
Log.i("height",""+height);
int inSampleSize = 1;

if (height > reqSize || width > reqSize) {

        if (width > height) {
            inSampleSize = Math.round((float) height / (float) reqSize);
        } else {
            inSampleSize = Math.round((float) width / (float) reqSize);
         }


}

return inSampleSize;

//Stacktrace
04-11 09:01:19.832: W/System.err(8832): java.lang.OutOfMemoryError
04-11 09:01:19.953: W/System.err(8832):     at  android.graphics.BitmapFactory.nativeDecodeStream(Native Method)
04-11 09:01:19.972: W/System.err(8832):     at android.graphics.BitmapFactory.decodeStream(BitmapFactory.java:529)
04-11 09:01:19.993: W/System.err(8832):     at com.scale.app.Resizer.resizeBitmap(Resizer.java:1290)

Answer 1

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图像尺寸:4000*3000 像素

当图像加载时:4000*3000*4 = ?知识库

因此，Android 设备的虚拟堆内存为:32 MB、64 MB、128 MB ...等等

如果您使用:

<application

    android:largeHeap="true">

</application>

这将使 VHM 增加一倍(如果 32 MB = 2* 32 MB)。但是这不是一个好方法，对操作系统有影响

您需要减小图像的尺寸。

---

使用下面的类并传递图像的路径和你想要的宽度，高度

Bitmap bitmap = BitmapSize.getDecodedBitmap(path, 400, 400);

类::::

public class BitmapSize{



public static Bitmap getDecodedBitmap(String path, float target_width, float target_height) {
    Bitmap outBitmap = null;
    try {
        Options decode_options = new Options();
        decode_options.inJustDecodeBounds = true;
        BitmapFactory.decodeFile(path,decode_options);  //This will just fill the output parameters
        int inSampleSize = calculateInSampleSize(decode_options, target_width, target_height);

        Options outOptions = new Options();
        outOptions.inJustDecodeBounds = false;
        outOptions.inSampleSize = inSampleSize;
        outOptions.inPreferredConfig = Bitmap.Config.ARGB_8888;
        outOptions.inScaled = false;

        Bitmap decodedBitmap = BitmapFactory.decodeFile(path,outOptions);
        outBitmap = Bitmap.createScaledBitmap(decodedBitmap,// (int)target_width, (int)target_height, true);
                (int)((float)decodedBitmap.getWidth() / inSampleSize),
                (int)((float)decodedBitmap.getHeight() / inSampleSize), true);
        System.out.println("Decoded Bitmap: Width "  + outBitmap.getWidth() + " Height = " + outBitmap.getHeight() + " inSampleSize = " + inSampleSize);

    } catch (Exception e) {
        // TODO: handle exception
    }

    return outBitmap;
}

public static int calculateInSampleSize(Options options, float reqWidth, float reqHeight) {
    final int height = options.outHeight;
    final int width = options.outWidth;
    int inSampleSize = 1;

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

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

        inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio;
    }

    return inSampleSize;
}

}