Updating TextView in onCreate()

Question

I want to update TextView in onCreate(), so that text should be set when Activity Interface appears, what I've tried is:

Java Code:

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_sem_selection);

    TextView T =(TextView)findViewById(R.id.textView1); 
    T.setText("required text"); 

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

but i get error when activity starts , as soon as i comment this line :

T.setText("required text");

App runs fine without error. How should I do this? Is there any other method?

Your `textView1` is probably in `PlaceholderFragment`. Move it to `onCreateView` — Apoorv, Jul 24 '14 at 05:32

score 1 · Accepted Answer · answered Jul 24 '14 at 05:33

1

You are referencing TextView T from fragment you will get null because in your activity you are using activity_sem_selection and getting TextView T from activity_sem_selection layout.

So use T in onCreateView method of fragment.

For example

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

        TextView T =(TextView)rootView.findViewById(R.id.textView1); 
        T.setText("required text"); 

        return rootView;
    }

Note : change fragment__sem_selection with your fragment layout.

answered Jul 24 '14 at 05:33

Giru Bhai

14,370
5
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1

And also, it is better practice to use lowercase letters for variables - `TextView t` and not `T` – gilonm Jul 24 '14 at 05:35
Thanks alot #Giru bhai :) it worked perfectly , now i just couldn't get the mistake i was making previously , it was a null pointer exception , i am a beginner , kindly elaborate , thanks in advance . – Adeel Ahmad Jul 24 '14 at 05:47
accepted :)p.s i just asked for a little explanation about my mistake , sir ' – Adeel Ahmad Jul 24 '14 at 05:53

score 0 · Answer 2 · answered Jul 24 '14 at 05:32

0

Remove

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

answered Jul 24 '14 at 05:32

Don Chakkappan

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Kaushik · Answer 3 · 2014-07-24T05:41:19.297

0

Check textView1 is present in activity_sem_selection layout.Otherwise you will get NPE.Try to place a TextView with id textView1 in activity_sem_selection layout. Otherwise you can remove those assignment and referencing for that TextView T and place those inside fragment's onCreateView(...).

edited Jul 24 '14 at 05:41

answered Jul 24 '14 at 05:34

Kaushik

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Updating TextView in onCreate()

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