Question

我有一个MediaStore.Images.Media.DATA uri图片如何使用该uri获取MediaStore.Images.ImageColumns.ORIENTATION？我收到了NullPointerException。

以下是我的代码，

private  int getOrientation(Context context, Uri photoUri) {

Log.v("orientatioon", "not crashed01");
Cursor cursor = context.getContentResolver().query(photoUri,
        new String[] { MediaStore.Images.ImageColumns._ID,MediaStore.Images.ImageColumns.ORIENTATION }, null, null, null);
Log.v("orientatioon", "not crashed02");


cursor.moveToFirst();
Log.v("orientatioon", "not crashed 03");
int i=cursor.getInt(cursor.getColumnIndexOrThrow(MediaStore.Images.ImageColumns.ORIENTATION));
Log.v("orientatioon", ""+i);
cursor.close();
return i;
}

我在cursor.moveToFirst（）代码行中获得NullPointerException。

Answer 1

实际上两个答案都是正确的，并且must可以同时使用。

/**
 * @return 0, 90, 180 or 270. 0 could be returned if there is no data about rotation
 */
public static int getImageRotation(Context context, Uri imageUri) {
    try {
        ExifInterface exif = new ExifInterface(imageUri.getPath());
        int rotation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_UNDEFINED);

        if (rotation == ExifInterface.ORIENTATION_UNDEFINED)
            return getRotationFromMediaStore(context, imageUri);
        else return exifToDegrees(rotation);
    } catch (IOException e) {
        return 0;
    }
}

public static int getRotationFromMediaStore(Context context, Uri imageUri) {
    String[] columns = {MediaStore.Images.Media.DATA, MediaStore.Images.Media.ORIENTATION};
    Cursor cursor = context.getContentResolver().query(imageUri, columns, null, null, null);
    if (cursor == null) return 0;

    cursor.moveToFirst();

    int orientationColumnIndex = cursor.getColumnIndex(columns[1]);
    return cursor.getInt(orientationColumnIndex);
}

private static int exifToDegrees(int exifOrientation) {
    if (exifOrientation == ExifInterface.ORIENTATION_ROTATE_90) {
        return 90;
    } else if (exifOrientation == ExifInterface.ORIENTATION_ROTATE_180) {
        return 180;
    } else if (exifOrientation == ExifInterface.ORIENTATION_ROTATE_270) {
        return 270;
    } else {
        return 0;
    }
}

Answer 2

请这样做。试一试

 final Uri imageUri = data.getData();

                        String[] columns = {MediaStore.Images.Media.DATA, MediaStore.Images.Media.ORIENTATION};

                        Cursor cursor = getContentResolver().query(imageUri, columns, null, null, null);


                        if (cursor == null) {

                            return;
                        }

                        cursor.moveToFirst();

                        int columnIndex = cursor.getColumnIndex(columns[0]);
                        int orientationColumnIndex = cursor.getColumnIndex(columns[1]);


                        String filePath = cursor.getString(columnIndex);
                        int orientation = cursor.getInt(orientationColumnIndex);

                        Log.d(TAG, "got image orientation "+orientation);

Answer 3

使用此method获取方向

public static int getExifOrientation(String filepath) {// YOUR MEDIA PATH AS STRING
        int degree = 0;
        ExifInterface exif = null;
        try {
            exif = new ExifInterface(filepath);
        } catch (IOException ex) {
            ex.printStackTrace();
        }
        if (exif != null) {
            int orientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, -1);
            if (orientation != -1) {
                switch (orientation) {
                case ExifInterface.ORIENTATION_ROTATE_90:
                    degree = 90;
                    break;
                case ExifInterface.ORIENTATION_ROTATE_180:
                    degree = 180;
                    break;
                case ExifInterface.ORIENTATION_ROTATE_270:
                    degree = 270;
                    break;
                }

            }
        }
        return degree;
    }

从MediaStore.Images.Media.DATA获取图像的方向

3 个答案: