无法通过从手机中选择图片来更改imageView（片段）

Question

通过查看和查看许多教程，我一直在寻找2天的答案，但我没有找到任何可以帮助我的方法。

我遇到了ImageView问题。我想通过从手机图库中选择一张图片来更改图像。我正在使用Android Studio。

如果你们能帮助我解决这个问题，我将非常感激。如果您需要任何进一步的信息，请不要犹豫与我联系。

提前致谢。来自瑞士的问候。

public class AddCategory extends Fragment{

private static final int IMAGE_PICKER_SELECT = 1;
Button b;
ImageView imageView;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View rootView = inflater.inflate(R.layout.fragment_addcategory, container, false);
    imageView = (ImageView)rootView.findViewById(R.id.imageView_add);
    b = (Button)rootView.findViewById(R.id.button_add);
    b.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent i = new Intent(Intent.ACTION_PICK, MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
            startActivityForResult(i,IMAGE_PICKER_SELECT );
        }
    });
    return rootView;
}

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    if(requestCode == IMAGE_PICKER_SELECT && requestCode == Activity.RESULT_OK && null != data){

        Uri selectedImage = data.getData();
        String[] filePathColumn = {MediaStore.Images.Media.DATA};
        Cursor cursor = getActivity().getContentResolver().query(selectedImage, filePathColumn, null, null, null);
        cursor.moveToFirst();

        int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
        String picturePath = cursor.getString(columnIndex);

        cursor.close();

        ImageView imageView = (ImageView)getActivity().findViewById(R.id.imageView_add);
        imageView.setImageBitmap(BitmapFactory.decodeFile(picturePath));

    } else {
        Toast.makeText(getActivity(), "Try Again!!", Toast.LENGTH_SHORT).show();
}
}

}