NullPointer while accessing field from fragment in onther fragment

Question

I got a nasty NullPointerException in Fragment while trying to access spinner in another Fragment. The code, which causes NPE:

public class FirstFirst extends Fragment{
    Spinner spinner;
    RadioGroup rg;
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
        View rootView = inflater.inflate(R.layout.first_first_fragment, container, false);
        spinner=(Spinner)rootView.findViewById(R.id.spinner1);
        return rootView;
    }
    @Override
    public void onViewCreated(View view, Bundle savedInstanceState){
        rg=(RadioGroup) getView().findViewById(R.id.RadioGroup2);
        rg.setOnCheckedChangeListener(new OnCheckedChangeListener(){

        @Override
        public void onCheckedChanged(RadioGroup arg0, int arg1) {
            spinner.setVisibility(View.GONE);
            if(arg1==0){
                spinner.setVisibility(View.VISIBLE);
            }
        });
    }
}

I know, that the Spinner itself is there, I can see it, but if I try to change its visibility with the code above i get the NPE.

@Edit:

The XML code:

<?xml version="1.0" encoding="utf-8"?>
<RadioGroup xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:id="@+id/RadioGroup2" >

    <RadioButton
        android:id="@+id/radioButton1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/pow" />
</RadioGroup>

@LogCat

05-28 13:54:52.681: E/AndroidRuntime(12841): FATAL EXCEPTION: main
05-28 13:54:52.681: E/AndroidRuntime(12841): Process: com.example.kuwa, PID: 12841 
05-28 13:54:52.681: E/AndroidRuntime(12841): java.lang.NullPointerException
05-28 13:54:52.681: E/AndroidRuntime(12841):    at com.example.kuwa.FirstFirst$1.onCheckedChanged(FirstFirst.java:26)
05-28 13:54:52.681: E/AndroidRuntime(12841):    at android.widget.RadioGroup.setCheckedId(RadioGroup.java:174)
05-28 13:54:52.681: E/AndroidRuntime(12841):    at android.widget.RadioGroup.access$600(RadioGroup.java:54)
05-28 13:54:52.681: E/AndroidRuntime(12841):    at android.widget.RadioGroup$CheckedStateTracker.onCheckedChanged(RadioGroup.java:358)
05-28 13:54:52.681: E/AndroidRuntime(12841):    at android.widget.CompoundButton.setChecked(CompoundButton.java:130)
05-28 13:54:52.681: E/AndroidRuntime(12841):    at android.widget.CompoundButton.toggle(CompoundButton.java:87)
05-28 13:54:52.681: E/AndroidRuntime(12841):    at android.widget.RadioButton.toggle(RadioButton.java:76)
05-28 13:54:52.681: E/AndroidRuntime(12841):    at android.widget.CompoundButton.performClick(CompoundButton.java:99)
05-28 13:54:52.681: E/AndroidRuntime(12841):    at android.view.View$PerformClick.run(View.java:18462)
05-28 13:54:52.681: E/AndroidRuntime(12841):    at android.os.Handler.handleCallback(Handler.java:733)
05-28 13:54:52.681: E/AndroidRuntime(12841):    at android.os.Handler.dispatchMessage(Handler.java:95)
05-28 13:54:52.681: E/AndroidRuntime(12841):    at android.os.Looper.loop(Looper.java:136)
05-28 13:54:52.681: E/AndroidRuntime(12841):    at android.app.ActivityThread.main(ActivityThread.java:5102)
05-28 13:54:52.681: E/AndroidRuntime(12841):    at java.lang.reflect.Method.invokeNative(Native Method)
05-28 13:54:52.681: E/AndroidRuntime(12841):    at java.lang.reflect.Method.invoke(Method.java:515)
05-28 13:54:52.681: E/AndroidRuntime(12841):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
05-28 13:54:52.681: E/AndroidRuntime(12841):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
05-28 13:54:52.681: E/AndroidRuntime(12841):    at dalvik.system.NativeStart.main(Native Method)

Your `spinnerview` is fine. issue is about your `RadioGroup`. — M D, May 28 '14 at 11:18
Please edit your question with the xml code. Try to avoid pasting code in comments. — Emmanuel, May 28 '14 at 11:34
@Simple Plan Are you sure it is that? Because I get the NPE exactly at: `spinner.setVisibility(View.GONE);` — user3212350, May 28 '14 at 11:36
@user3212350 first remove this `spinner=(Spinner)rootView.findViewById(R.id.spinner1);` — M D, May 28 '14 at 11:37
You can not write IDs with uppercase letters, only [a-z] and _ are allowed — Alejandro Alcalde, May 28 '14 at 11:54
It doesn't matter how i wrote ID. Well it is exactly what it looks like. Adding a on checked change listener to radio group — user3212350, May 28 '14 at 12:01
@user3212350 I think only [a-z0-9_.] are allowed. Check this: http://stackoverflow.com/questions/7305483/capital-letters-not-allowed-in-android-res — Alejandro Alcalde, May 28 '14 at 12:08
R.layout.first_first_fragment this layout must contain the spinner in order for u to use it @user3212350 — Rat-a-tat-a-tat Ratatouille, May 28 '14 at 13:03

Woodstown · Answer 1 · 2014-05-28T12:38:48.137

0

Use setVisibility(View.INVISIBLE); instead of setVisibility(View.GONE) if you intend to make it visible again later.

edited May 28 '14 at 12:38

answered May 28 '14 at 11:59

Woodstown

26
5

`View.INVISIBLE` does not the same as `View.GONE`. `View.GONE` removes the `View` from the hierarchy and `View.INVISIBLE` it only changes visibility; the `View` is kept on the hierarchy. – Emmanuel May 28 '14 at 12:03
I know the difference, it looks to me like View.INVISIBLE is what OP wants to achieve. – Woodstown May 28 '14 at 12:07
Ok, thanks, but It doesn't help me with this problem – user3212350 May 28 '14 at 12:14
Are you still getting the NPE at spinner.setVisibility(View.INVISIBLE); – Woodstown May 28 '14 at 12:15
Well then spinner must be null, have you got the correct id name for it? I'm assuming spinner is in the same fragment as the radio group? – Woodstown May 28 '14 at 12:30
Please post the fragment containing spinner1 – Woodstown May 28 '14 at 12:31

Alejandro Alcalde · Answer 2 · 2014-05-28T12:26:15.903

0

Try this:

rg=(RadioGroup) view.findViewById(R.id.RadioGroup2)

instead of this

rg=(RadioGroup) getView().findViewById(R.id.RadioGroup2)

The parameter view of onViewCreated is The View returned by onCreateView

edited May 28 '14 at 12:26

answered May 28 '14 at 12:02

Alejandro Alcalde

5,990
6
39
79

It didn't change anything, still same exception in same line – user3212350 May 28 '14 at 12:11
Try changing the ID to lowercase please, just to see if that is the problem – Alejandro Alcalde May 28 '14 at 12:16
Why can't I have uppercase letters if IDE makes ID with upperCase letters automatically? It didn't change anything – user3212350 May 28 '14 at 12:16
Umm, sorry, I was confused, the restriction is only for drawables. Sorry ;-) – Alejandro Alcalde May 28 '14 at 12:25

score 0 · Answer 3 · answered May 28 '14 at 12:26

0

What is name of xml you posted? What is code for first_first_fragment layout. If you don't have spinner with id spinner1 in it, then spinner is null.

answered May 28 '14 at 12:26

Zoran

1,484
1
10
13

NullPointer while accessing field from fragment in onther fragment

3 Answers3