Two constructors for a Fragment

Question

Is it possible to have two different constructors for the same Fragment ?

Here's my case : I have Fragment_A and Fragment_B which are almost identically, except one gets an Integer and the other a String.

Can I have something like this :

public static VideoListFragment newInstanceA(String filterString) {
    VideoListFragment myFragment = new VideoListFragment();

    Bundle args = new Bundle();
    args.putString(FILTER, filterString);
    myFragment.setArguments(args);

    return myFragment;
}

public static VideoListFragment newInstanceB(String subjectId) {
    VideoListFragment myFragment = new VideoListFragment();

    Bundle args = new Bundle();
    args.putString(POSITION, subjectId);
    myFragment.setArguments(args);

    return myFragment;
}

If this is possible then how am I going to get in onCreate() the argument ? I have somehow to check if getArguments()` contains FILTER String or POSITION Integer.

waqaslam · Answer 1 · 2016-05-18T18:29:49.383

3

You cannot use an exact same method signature to distinguish between different input behaviors. However, you can extend input parameters to make it more versatile. Something like this would help:

public class VideoListFragment extends Fragment {    
    public static VideoListFragment newInstance(String type, String val) {
        VideoListFragment myFragment = new VideoListFragment();

        Bundle args = new Bundle();
        args.putString(type, val);
        myFragment.setArguments(args);

        return myFragment;
    }
}

and later use it as below:

VideoListFragment frag1 = VideoListFragment.newInstance(FILTER, "value");  //for Filter
VideoListFragment frag2 = VideoListFragment.newInstance(POSITION, "value");//for Position

edited May 18 '16 at 18:29

answered May 18 '16 at 18:23

waqaslam

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But I have different names : `newInstanceA` and `newInstanceB` . Will it work like this? Otherwise, your answer is a good alternative option for me. – Mes May 19 '16 at 05:08
1

Yes, if you provide separate names then it will work, but that is unnecessary redundancy for such a minor thing to achieve. – waqaslam May 19 '16 at 09:09

score 0 · Answer 2 · answered May 18 '16 at 18:28

0

Android docs discourages the use of constructors while working with fragments; you should use bundle instead.

answered May 18 '16 at 18:28

DEEPANKUR SADANA

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any reference to that? – waqaslam May 18 '16 at 18:30
http://stackoverflow.com/questions/9245408/best-practice-for-instantiating-a-new-android-fragment – DEEPANKUR SADANA May 18 '16 at 18:34
@DEEPANKURSADANA You cannot override no-args constructor anyhow, as it will fail with an error. However, if you want, you may use a constructor as long as it has one or more input parameters. – waqaslam May 18 '16 at 18:41

Two constructors for a Fragment

2 Answers2