java - Android TextView SetText null object reference error

I am new to android and I am getting a

Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference

error on my app. I have read other questions on here like this one - java.lang.NullPointerException - setText on null object reference but I still get the same issue. My format is a little bit different as this is done in a Fragment and what I am doing is having a Custom Adapter from a listview. Here is my code

fragment_song_genre.xml

xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:bind="http://schemas.android.com/tools">



            name="handler"
        type="com.mgrmobi.joox.fragments.FilterSongGenreFragment" />




    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#000">

            android:id="@+id/toprow"

        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="24dp">

                    android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentLeft="true"
            android:layout_centerVertical="true"
            android:layout_marginLeft="16dp"

            android:background="@null"
            android:onClick="@{ handler.onCloseClicked }"
            android:src="@drawable/search_close" />

                    android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentLeft="true"
            android:layout_centerVertical="true"
            android:layout_marginLeft="80dp"

            android:text="Genre"
            android:textColor="#fff"
            android:textSize="20sp" />

                    android:onClick="@{ handler.reset }"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentRight="true"
            android:layout_centerVertical="true"

            android:layout_marginRight="15dp"
            android:text="@string/reset"
            android:textAllCaps="true"
            android:textColor="#fff"
            android:textSize="12sp" />

    

            android:id="@+id/list"

        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_below="@id/toprow"
        android:layout_marginTop="24dp">

That is the main page and it has a Listview in the Bottom and here is the fragment that calls that xml layout

 public class FilterSongGenreFragment extends BaseFragment {

    private SongGenreBinding binding;
    private ArrayList genres;
    String[] names= {"Johm","Paul","Mike"};

    @Override
    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {

        super.onCreateContextMenu(menu, v, menuInfo);
    }


    private static final String GENRES_KEY = "genres";

    public static FilterSongGenreFragment newInstance(ArrayList genres) {

        Bundle args = new Bundle();
        args.putStringArrayList(GENRES_KEY, genres);

        FilterSongGenreFragment fragment = new FilterSongGenreFragment();
        fragment.setArguments(args);
        return fragment;
    }

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        binding = DataBindingUtil.inflate(inflater, R.layout.fragment_song_genre, container, false);
        binding.setHandler(this);

        genres = getArguments().getStringArrayList(GENRES_KEY);

        initList();
        return binding.getRoot();
    }

    private void initList() {

    // ArrayAdapter adapter = new ArrayAdapter(getActivity(), R.layout.genre_list_text, android.R.id.text1, genres);
     FilterSongsAdapter filterSongsAdapter= new FilterSongsAdapter(getActivity(),names);



        binding.list.setAdapter(filterSongsAdapter);

        binding.list.setOnItemClickListener(new AdapterView.OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView adapterView, View view,int position, long l) {
               ((SongFilterListener) getActivity()).onGenreSelected(genres.get(position));
/*

                    textView = (ImageView) view.findViewById(R.id.selected_genre);
                    textView.setVisibility(View.VISIBLE);
*/
              //  close();
            }

        });

    }


    private void close() {
        getActivity().getFragmentManager().beginTransaction().remove(this).commit();
    }

    public void onCloseClicked(View view) {
        close();
    }

    public void reset(View view) {
        ((SongFilterListener) getActivity()).onResetFilters();

        close();
    }

}

Here is the xml for the listview custom style genre_list_text.xml

    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal">

        android:id="@android:id/text1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"

    android:gravity="center_vertical|left"
    android:text="Genre"
    android:paddingBottom="16dp"
    android:paddingLeft="4dp"
    android:paddingTop="16dp"
    android:textColor="#fff"
    android:textSize="16sp" />

                    android:id="@+id/selected_genre"

            android:layout_height="24dp"
            android:layout_width="24dp"
            android:visibility="invisible"
            android:src="@drawable/check_circle"
            android:layout_marginStart="140dp"
            android:layout_centerVertical="true" />

    

and here is my adapter and as stated before the error happens in the SetText area

  public class FilterSongsAdapter extends ArrayAdapter {

    private Context c;
    String[] names= {};
    LayoutInflater inflater;

    public FilterSongsAdapter(Context context,String[] names) {
        super(context,R.layout.genre_list_text,names);

        this.c=context;
        this.names=names;

    }

    public static class ViewHolder {

       TextView text1;



    }



    @Override
    public View getView(int position,View convertView,ViewGroup parent) {
        ViewHolder holder;
     if(convertView==null){
         holder  = new ViewHolder();
         inflater = (LayoutInflater) c.getSystemService(Context.LAYOUT_INFLATER_SERVICE);

         convertView = inflater.from(c).inflate(R.layout.genre_list_text, null);
         // Initialize
         holder.text1=(TextView) convertView.findViewById(R.id.text1);

          convertView.setTag(holder);
    }else {
         holder = (ViewHolder) convertView.getTag();
     }

        holder.text1.setText(names[position]);


        return convertView;
    }




}

The SetText inside the GetView is throwing the exception every time, that TextView should have 3 objects names from the Names String Array which I have seen that it has. Based on the error I know that i'm setting the SetText before the FindByID method locates the TextView but I have moved things around and nothing works. Any help would be great . I also been following this tutorial for reference https://www.youtube.com/watch?v=99C_UpLcBRk . I do not know if maybe with a Fragment things are different.

Answer

in your layout you have given default id to TextView android:id="@android:id/text1".

and in JAVA file you are giving R.id.text1

make changes in xml or java.

ether change in xml from android:id="@android:id/text1" to android:id="@+id/text1"
or in java android.R.id.text1

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I have tried:

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But I want it to be editable in the design section!

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public class A {
    public void f(A a) {
        System.out.print("in A ");

    }
}

public class B extends A {

    public static void main(String[] args) {
        B b = new B();
        A a = new A();
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        b.f(a);

    }
}

Why by adding the following method in B class there will be a compilation error?

It's known that if method throws something, it doesn't have to be declared in the method header...

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Answer

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When Bruce is left broken and suffering in the Prison Pit, Bane explains that this is where he suffered and where Bruce will fully realize his failure with Gotham, and then be killed.

During his time there, the Doctor and his friend explain that Bane owns the prison, and their only duty is to keep him alive until Bane wants to kill him. However, they seem to turn around, heal his back and start encouraging him to find the will and ability to climb out of the pit.

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Does anybody knows how can I get all the HTML tags that exist in a page?

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This will get all the tags, but my requirement is

• get a first parent tag and all the child tags under it



• get the next parent tag and all the child tags under it and so on

I need to get the tags in a kind of tree-structure. Prefer to do that with Javascript or JQuery.

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Blabla
    

      






     
   
 

Should Return:

html

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2. body-->h1,(div-->table-->tr-->td,td)

Answer

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Live example

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Of course there are a dozen ways to spin this. For instance, an array of objects instead:

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@Override
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@Override
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It is the last 4 lines in code.