ArrayAdapter causing java.lang.NullPointerException

Question

I am trying to add an item to my ArrayAdapter after an item is saved but it throws a NullPointerException. Can anyone tell me whats causing this? It looks like the info saves to the DB and is there on reloading the app.

Here's my java file, the line in question is

adapter.addAll(character);

Heres the full file

package com.fasttracksites.dnd5e;

import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Adapter;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.TextView;

import com.getbase.floatingactionbutton.FloatingActionButton;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {
    private CustomCursorAdapter customAdapter;
    private List<Character> characters;
    private static final int ENTER_DATA_REQUEST_CODE = 1;
    private ListView listView;
    private Context ctx;
    private ArrayAdapter<Character> adapter;
    private static final String TAG = MainActivity.class.getSimpleName();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        setTitle("Choose a Character");
        ctx = getApplicationContext();

        listView = (ListView) findViewById(R.id.characters);
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                Log.d(TAG, "clicked on item: " + position);
            }
        });

        // Construct the data source
        ArrayList<Character> arrayOfCharacters = new ArrayList<Character>();
        // Create the adapter to convert the array to views
        CharacterListAdapter adapter = new CharacterListAdapter(this, arrayOfCharacters);
        // Attach the adapter to a ListView
        listView.setAdapter(adapter);

        characters = Character.listAll(Character.class);
        adapter.addAll(characters);

        final FloatingActionButton actionA = (FloatingActionButton) findViewById(R.id.addCharacter);
        actionA.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View view) {
                actionA.setTitle("Add Character clicked");
                startActivityForResult(new Intent(MainActivity.this, AddCharacterActivity.class), ENTER_DATA_REQUEST_CODE);
            }
        });
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {

        super.onActivityResult(requestCode, resultCode, data);

        if (requestCode == ENTER_DATA_REQUEST_CODE && resultCode == RESULT_OK) {
            Character character = new Character(data.getExtras().getString("tag_character_name"), data.getExtras().getString("tag_character_class"), data.getExtras().getInt("tag_character_level"));
            character.save();
            adapter.addAll(character); // This is causing the null pointer exception
        }
    }
}

class CharacterListAdapter extends ArrayAdapter<Character> {
    // View lookup cache
    private static class ViewHolder {
        TextView name;
        TextView classAndLevel;
    }
    public CharacterListAdapter(Context context, ArrayList<Character> characters) {
        super(context, R.layout.list_characters, characters);
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        // Get the data item for this position
        Character character = getItem(position);
        // Check if an existing view is being reused, otherwise inflate the view
        ViewHolder viewHolder; // view lookup cache stored in tag
        if (convertView == null) {
            viewHolder = new ViewHolder();
            LayoutInflater inflater = LayoutInflater.from(getContext());
            convertView = inflater.inflate(R.layout.list_characters, parent, false);
            viewHolder.name = (TextView) convertView.findViewById(R.id.tvCharacterName);
            viewHolder.classAndLevel = (TextView) convertView.findViewById(R.id.tvCharacterClassAndLevel);
            convertView.setTag(viewHolder);
        } else {
            viewHolder = (ViewHolder) convertView.getTag();
        }
        // Populate the data into the template view using the data object
        viewHolder.name.setText(character.name);
        viewHolder.classAndLevel.setText(character.chosenClass + " - Level " + character.level);
        // Return the completed view to render on screen
        return convertView;
    }
}

This is the error in console:

05-03 21:09:35.628    2106-2106/com.fasttracksites.dnd5e E/AndroidRuntime﹕ FATAL EXCEPTION: main
    java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=1, result=-1, data=Intent { cmp=com.fasttracksites.dnd5e/.AddCharacterActivity (has extras) }} to activity {com.fasttracksites.dnd5e/com.fasttracksites.dnd5e.MainActivity}: java.lang.NullPointerException
            at android.app.ActivityThread.deliverResults(ActivityThread.java:3367)
            at android.app.ActivityThread.handleSendResult(ActivityThread.java:3410)
            at android.app.ActivityThread.access$1100(ActivityThread.java:141)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1304)
            at android.os.Handler.dispatchMessage(Handler.java:99)
            at android.os.Looper.loop(Looper.java:137)
            at android.app.ActivityThread.main(ActivityThread.java:5103)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:525)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
            at dalvik.system.NativeStart.main(Native Method)
     Caused by: java.lang.NullPointerException
            at com.fasttracksites.dnd5e.MainActivity.onActivityResult(MainActivity.java:78)
            at android.app.Activity.dispatchActivityResult(Activity.java:5322)
            at android.app.ActivityThread.deliverResults(ActivityThread.java:3363)
            at android.app.ActivityThread.handleSendResult(ActivityThread.java:3410)
            at android.app.ActivityThread.access$1100(ActivityThread.java:141)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1304)
            at android.os.Handler.dispatchMessage(Handler.java:99)
            at android.os.Looper.loop(Looper.java:137)
            at android.app.ActivityThread.main(ActivityThread.java:5103)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:525)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
            at dalvik.system.NativeStart.main(Native Method)

The code that sends the intent is:

package com.fasttracksites.dnd5e;


        import android.content.Intent;
        import android.os.Bundle;
        import android.support.v7.app.AppCompatActivity;
        import android.view.View;
        import android.widget.EditText;

public class AddCharacterActivity extends AppCompatActivity {

    EditText editTextCharacterName;
    EditText editTextCharacterClass;
    EditText editTextCharacterLevel;

    /**
     * Called when the activity is first created.
     */
    @Override
    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_add_character);
        setTitle("Enter Your Character Info");

        editTextCharacterName = (EditText) findViewById(R.id.et_character_name);
        editTextCharacterClass = (EditText) findViewById(R.id.et_character_class);
        editTextCharacterLevel = (EditText) findViewById(R.id.et_character_level);
    }

    public void onClickAdd (View btnAdd) {

        String characterName = editTextCharacterName.getText().toString();
        String characterClass = editTextCharacterClass.getText().toString();
        Integer characterLevel = Integer.parseInt(editTextCharacterLevel.getText().toString());

        if ( characterName.length() != 0 && characterClass.length() != 0 ) {

            Intent newIntent = getIntent();
            newIntent.putExtra("tag_character_name", characterName);
            newIntent.putExtra("tag_character_class", characterClass);
            newIntent.putExtra("tag_character_level", characterLevel);

            this.setResult(RESULT_OK, newIntent);

            finish();
        }
    }
}

ρяσѕρєя K · Accepted Answer · 2015-05-04 01:22:52Z

1

Change :

     CharacterListAdapter adapter = 
           new CharacterListAdapter(this, arrayOfCharacters);

to

      adapter = new CharacterListAdapter(this, arrayOfCharacters);

Problem is occurring because adapter is null in onActivityResult method when calling adapter.addAll method

edited May 4, 2015 at 1:22

answered May 4, 2015 at 1:21

ρяσѕρєя K

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3 Comments

rafaelc Over a year ago

How the hell was he able to declare two variables with the same name?

ρяσѕρєя K Over a year ago

@RafaelCardoso: OP is able to declare two variables with same name due to variable scope. first OP is declared as class level and second is as method level which is accessible only inside onCreate method

spyke01 Over a year ago

Thanks, I ended up cleaning up that right before I saw your post and it fixed it.

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