android interface object is null

Question

I have a childfragment which has -

private FavouriteMessageListener favouriteMessageListener;

msgListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                FavouriteMessageWrapper favouriteMessage =  favourites.get(position);
                String favoriteMessage = favouriteMessage.getText();
                //Need to notify the interface about it
                favouriteMessageListener.favouriteMessageString(favoriteMessage);
                }
            });

My Interface

public interface FavouriteMessageListener {
     void favouriteMessageString(String favouriteMessage);
}

My MainFragment

@Override
    public void favouriteMessageString(String favouriteMessage) {

    }

Why my favouriteMessageListener is null? What is wrong with my implementation... I just need to get the value of string in MainFragment using this interface. How do I do?

check [this](http://stackoverflow.com/a/12311939/5296734) out a possible help — android_griezmann, Aug 17 '16 at 08:03

Vygintas B · Answer 1 · 2016-08-17T08:53:43.620

0

Try this

In your adapter

 // Define listener member variable
private static OnItemClickListener listener;
// Define the listener interface
public interface OnItemClickListener {
    void onItemClick(View itemView, int position, String favoriteMessaage);
}
// Define the method that allows the parent activity or fragment to define the listener
public void setOnItemClickListener(OnItemClickListener listener) {
    this.listener = listener;
}

In your adapters ViewHolder:

plus.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                if (listener != null)
                    listener.onItemClick(v, k, favoriteMessage);
            }
        });

In your Fragment:

adapter.setOnItemClickListener(new MenuListCustomAdapter.OnItemClickListener() {
        @Override
        public void onItemClick(View view, int position, String favoriteMessage) {


              // you can get your String here
              //you can check which view was clicked
               if(view.getId() == R.id.viewID){

                 //do your stuff here
               }
      }
    });

edited Aug 17 '16 at 08:53

answered Aug 17 '16 at 08:04

Vygintas B

1,624
13
31

Actually I want to do it in fragment... I dont want to do in adapter – Maria Anasthesia Aug 17 '16 at 08:58
You want to get string from adapter to your fragment. This example indeed does that – Vygintas B Aug 17 '16 at 08:59
No. I have a childfragment that has itemclick listener. From there I get a string as shown in my question. From there I need to notify my interface – Maria Anasthesia Aug 17 '16 at 09:00
Well my interface approach should work with your case too. Just use it in childfragment instead of adapter – Vygintas B Aug 17 '16 at 09:52

android interface object is null

1 Answers1