myView.setText() crashes android app when run

Question

My app has a button and a text view. When the button is pressed it changes the text view text to a new string, but it crashes when it tries to change the text. There are no errors or warning. I have included the code. Press is the onClick function of the button.

package com.example.testexample;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v7.app.ActionBarActivity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends ActionBarActivity {

    public TextView myView;
    public Button button;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        myView = (TextView) findViewById(R.id.textView1);
        button = (Button) findViewById(R.id.button1);

        if (savedInstanceState == null) {
            getSupportFragmentManager().beginTransaction()
                    .add(R.id.container, new PlaceholderFragment())
                    .commit();
        }
    }


   @Override
    public boolean onCreateOptionsMenu(Menu menu) {

        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    /**
     * A placeholder fragment containing a simple view.
     */
    public static class PlaceholderFragment extends Fragment {

        public PlaceholderFragment() {
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.fragment_main, container, false);
            return rootView;
        }
    }

    public void press(View view){

        myView.setText("Changed");

    }

}

It is defined in fragment_main.xml. There is no error, the app just crashes. — user3817902, Jul 08 '14 at 19:49
Do you get any log at all? If not then restart your emulator. — Simas, Jul 08 '14 at 19:50
Woops! Yeah just saw haha! Hmm bizarre! Are you sure there's nothing being output? — bdavies6086, Jul 08 '14 at 19:50
@user3817902 Well there's your issue. You're inflating `activity_main`, not `fragment_main`. Either move your button and textview declarations to your PlaceHolderFragment or change `R.layout.activity_main` to `R.layout.fragment_main` — Andrew Schuster, Jul 08 '14 at 19:51
I changed the declaration of the objects to activity_main, that fixed the problem. Thanks a lot. — user3817902, Jul 08 '14 at 19:55

score 1 · Answer 1 · answered Jul 08 '14 at 19:54

Declare your TextView inside onCreateView(), on your Fragment (because your TextView is on the Fragment layout file), not in your Activity. Like this:

/**
     * A placeholder fragment containing a simple view.
     */
public static class PlaceholderFragment extends Fragment {

    public PlaceholderFragment() {
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_main, container, false);
        myView = (TextView) rootView.findViewById(R.id.textView1);
        return rootView;
    }
}

myView.setText() crashes android app when run

1 Answers1