CODEWITHSUNDEEP
android
Bryan
Bryan

Reputation: 55

Android error with setAdapter in android ArrayAdapter

I have been stuck on this problem for the last few hours so any help will be very much appreciated. Im getting this error Attempt to invoke virtual method 'void android.widget.ListView.setAdapter(android.widget.ListAdapter)' on a null object reference

ArrayAdapter class

public class LocationsAdapter extends ArrayAdapter<String> {

public LocationsAdapter(Context context, ArrayList<String> locations) {
    super(context, R.layout.location_list, locations);
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {

    LayoutInflater layoutInflater = LayoutInflater.from(getContext());
    View customView = layoutInflater.inflate(R.layout.location_list, parent, false);
    String name = getItem(position);
    TextView textView = (TextView)customView.findViewById(R.id.locationTF);
    textView.setText(name);

    return customView;
}

}

activity_maps.xml

<ListView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/listViewLocations" />

location_list.xml

 <TextView
    android:layout_width="135dp"
    android:layout_height="wrap_content"
    android:textAppearance="?android:attr/textAppearanceMedium"
    android:id="@+id/locationTF"
    android:layout_weight="0.03" />

MapsActivity class 

private ArrayAdapter<String> adapter;
.
.
.
public void initAdapter(){
    ArrayList<String> sl = new ArrayList<>();
    sl.add("b");
    adapter = new LocationsAdapter(this, sl);

    ListView listView = (ListView) findViewById(R.id.listViewLocations);
    listView.setAdapter(adapter);

    listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

        }
    });
}

Upvotes: 0

Views: 898

Answers (1)

OneCricketeer
OneCricketeer

Reputation: 192033

Please make sure you are using the correct layout file before you use findViewById with any id contained in that layout. 

setContentView(R.layout.activity_maps);

Your problem is findViewById returned null because it couldn't find the id in the layout you've used

Upvotes: 1

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