Nullpointerexcepiton on cursor while selecting photo from gallery on dialog fragment

Question 1

How do you start your Activity and from where? If you pass your result trough your MainActivity, you can try to make a new function in your DialogFragment like this:

public void onMyActivityResult(Context main, int resultCode... an so on){

     main.getContentResolver.......

}

Edit: i have done it in this way:

Get the Activity in onCreate:

@Override
    public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    mActivity = (MainActivity) this.getActivity();
    }

then:

     @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
       if (requestCode == REQUEST_GALLERY && resultCode == Activity.RESULT_OK) {
           ...

            Uri selectedImage = data.getData();
            String path = getRealPathFromURI(selectedImage);
           ...
            reloadImages();

        }
        super.onActivityResult(requestCode, resultCode, data);
        }

and:

 private String getRealPathFromURI(Uri contentURI) {
    Cursor cursor = mActivity.getContentResolver().query(contentURI, null, null, null, null);
    if (cursor == null) { // Source is Dropbox or other similar local file
                  // path
        return contentURI.getPath();
    } else {
        cursor.moveToFirst();
        int idx = cursor.getColumnIndex(MediaStore.Images.ImageColumns.DATA);
        String path = cursor.getString(idx);
        cursor.close();
        return path;
    }
    }

Question 2

The problem is probably because getActivity() returns null in this line

Cursor cursor = getActivity().getContentResolver().query(selectedImage, filePathColumn, null, null, null);

It occurs when your fragment is not attached to an activity. I see 2 possible causes :

You call getActivity() too soon in the fragment lifecycle. You need to wait for the invocation of onAttach(Activity) before playing with getActivity()
Your fragment has been detached from the activity, check the return of Fragment.isAdded() to ensure your fragment is still attached.

Question 3

For choosing the Image from Gallery int PICK_IMAGE = 1;

public void getGalleryImage() {
        Intent intent = new Intent();
        intent.setType("image/*");
        intent.setAction(Intent.ACTION_GET_CONTENT);
        activity.startActivityForResult(Intent.createChooser(intent,"Select Picture"), PICK_IMAGE);
        }

On Activity Result

@Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (resultCode != Activity.RESULT_CANCELED) {
            if (requestCode == PICK_IMAGE) {
                String selectedImagePath = getAbsolutePath(data.getData());
                Log.d("GetImage","Selected Image Path "+selectedImagePath )
            } else {
                super.onActivityResult(requestCode, resultCode, data);
            }
        }
}

// Get Image Path

public String getAbsoluteImagePath(Uri uri) {
        String[] projection = { MediaColumns.DATA };
        @SuppressWarnings("deprecation")
        Cursor cursor = activity.managedQuery(uri, projection, null, null, null);
        if (cursor != null) {
            int column_index = cursor.getColumnIndexOrThrow(MediaColumns.DATA);
            cursor.moveToFirst();
            return cursor.getString(column_index);
        } else
            return null;
    }

Question 4

I have done with this...and it works well

 protected void onActivityResult(int requestCode, int resultCode, Intent 
 data) {
    super.onActivityResult(requestCode, resultCode, data);
    if (requestCode == PICK_IMAGE_REQUEST && resultCode == RESULT_OK) {

        Uri selectedImage = data.getData();
        URI = Uri.parse("file://" + selectedImage);
    }
}

Question 5

 private String getRealPathFromURI(Uri selectImagePath) {
    Cursor cursor = mActivity.getContentResolver().query(selectImagePath, null, null, null, null);
    if (cursor == null) { //this return actual path from storage
                
        return contentURI.getPath();
    } else {
        cursor.moveToFirst();
        int idx = cursor.getColumnIndex(MediaStore.Images.ImageColumns.DATA);
        String path = cursor.getString(idx);
        cursor.close();
        return path;
    }
    }