在imageView随机问题中未设置位图

Question

我正在尝试从设备存储中获取文件并在图像视图中显示它。 有时候它工作得非常好，但有时却没有。虽然位图在那里，但图像视图仍然是黑色。

请建议。

存储文件位置

 file:/storage/emulated/0/Download/Full-hd-nature-wallpapers-free-download2.jpg

返回位图的方法

public static Bitmap convertToBitmap（File file）{

    URI uri = null;
    try {
          uri = file.toURI();            
       BitmapFactory.Options options = new BitmapFactory.Options();            
        options.inSampleSize = 1;            
        Bitmap bmp = BitmapFactory.decodeStream(uri.toURL().openStream(), new Rect(), options);

       //bmp.recycle();
        return bmp;

    } catch (Exception e) {
        return null;
    }//catch
}

设置图像

      imageViewPatientImage.setImageBitmap(convertToBitmap(new File(mImagePath));

Answer 1

试试这个：

  Bitmap bitmap = getThumbnail(uri);
  showImage.setImageBitmap(bitmap);

传递优化位图：

 public  Bitmap getThumbnail(Uri uri) throws FileNotFoundException, IOException{
    InputStream input = getContext().getContentResolver().openInputStream(uri);

    BitmapFactory.Options onlyBoundsOptions = new BitmapFactory.Options();
    onlyBoundsOptions.inJustDecodeBounds = true;
    onlyBoundsOptions.inDither=true;//optional
    onlyBoundsOptions.inPreferredConfig=Bitmap.Config.ARGB_8888;//optional
    BitmapFactory.decodeStream(input, null, onlyBoundsOptions);
    input.close();
    if ((onlyBoundsOptions.outWidth == -1) || (onlyBoundsOptions.outHeight == -1))
        return null;

    int originalSize = (onlyBoundsOptions.outHeight > onlyBoundsOptions.outWidth) ? onlyBoundsOptions.outHeight : onlyBoundsOptions.outWidth;

    double ratio = (originalSize > 500) ? (originalSize / 500) : 1.0;

    BitmapFactory.Options bitmapOptions = new BitmapFactory.Options();
    bitmapOptions.inSampleSize = getPowerOfTwoForSampleRatio(ratio);
    bitmapOptions.inDither=true;//optional
    bitmapOptions.inPreferredConfig=Bitmap.Config.ARGB_8888;//optional
    input = getContext().getContentResolver().openInputStream(uri);
    Bitmap bitmap = BitmapFactory.decodeStream(input, null, bitmapOptions);
    input.close();
    return bitmap;
}

private static int getPowerOfTwoForSampleRatio(double ratio){
    int k = Integer.highestOneBit((int)Math.floor(ratio));
    if(k==0) return 1;
    else return k;
}