CODEWITHSUNDEEP
androidlistviewfragment
Florian Walther
Florian Walther

Reputation: 6961

Android: findViewById on Fragment Item returns null

i cant figure it out.

When sometimes clicks on an Item in my ListView, i want to open a Fragment and set 1 EditText and 3 RadioButtons according to the values of the list item that was clicked. 

public void openEditTask(int position) {
    if (newTaskFragment != null) closeNewTaskFragment();
    if (editTaskFragment != null) closeEditTaskFragment();

    editTaskFragment = new EditTaskFragment();
    transaction = getSupportFragmentManager().beginTransaction();
    transaction.setCustomAnimations(R.anim.enter_from_right, R.anim.exit_to_right);
    transaction.replace(R.id.edit_task_frame_xml, editTaskFragment);

    //set EditText and RadioButtons according to clicked item
    EditText editTaskName = (EditText) findViewById(R.id.edit_task_name_xml);
    RadioButton easyButton = (RadioButton) findViewById(R.id.edit_radio_button_easy_xml);
    RadioButton mediumButton = (RadioButton) findViewById(R.id.edit_radio_button_medium_xml);
    RadioButton hardButton = (RadioButton) findViewById(R.id.edit_radio_button_hard_xml);
    //Edit Text
    editTaskName.setText(mTaskList.get(position).getName());
    //Radio Buttons
    if (mTaskList.get(position).getDifficultyNumber() == 1) {
        easyButton.isChecked();
    } else if (mTaskList.get(position).getDifficultyNumber() == 2) {
        mediumButton.isChecked();
    } else hardButton.isChecked();

    transaction.commit();

}

Why do i get a null pointer exception? I dont understand it.

Upvotes: 0

Views: 68

Answers (1)

Shalon Isaac
Shalon Isaac

Reputation: 76

You should handle your instances in the Fragment class. You can set the position as an Argument and get the data from wherever you need and show the view.

Your EditTaskFragment should look something like this:

public class EditTaskFragment extends Fragment {

    private static final String POSITION_PARAM = "positionParam";

    private int position;

    public EditTaskFragment() {
    }

    public static EditTaskFragment newInstance(int position) {
        EditTaskFragment fragment = new EditTaskFragment();
        Bundle args = new Bundle();
        args.putInt(POSITION_PARAM, position);
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (getArguments() != null) {
            position = getArguments().getInt(POSITION_PARAM);
        }
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.yourfragmentlayout, container, false);
        EditText editTaskName = (EditText) v.findViewById(R.id.edit_task_name_xml);
        RadioButton easyButton = (RadioButton) v.findViewById(R.id.edit_radio_button_easy_xml);
        RadioButton mediumButton = (RadioButton) v.findViewById(R.id.edit_radio_button_medium_xml);
        RadioButton hardButton = (RadioButton) v.findViewById(R.id.edit_radio_button_hard_xml);
        //Edit Text
        editTaskName.setText(mTaskList.get(position).getName());
        //Radio Buttons
        if (mTaskList.get(position).getDifficultyNumber() == 1) {
            easyButton.isChecked();
        } else if (mTaskList.get(position).getDifficultyNumber() == 2) {
            mediumButton.isChecked();
        } else
            hardButton.isChecked();

        return v;
      }    
}

Then, your openEditTask function should be:

public void openEditTask(int position) {
    if (newTaskFragment != null) closeNewTaskFragment();
    if (editTaskFragment != null) closeEditTaskFragment();

    editTaskFragment = EditTaskFragment.newInstance(position);
    transaction = getSupportFragmentManager().beginTransaction();
    transaction.setCustomAnimations(R.anim.enter_from_right, R.anim.exit_to_right);
    transaction.replace(R.id.edit_task_frame_xml, editTaskFragment);    
    transaction.commit();

}

So, you have to look for the data according the position the user selected, in the Fragment class.

I hope this answer your question

Upvotes: 1

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