Android: seekbar.setProgress() gives Nullpointer exception

Question

I have used seekbar like quite a few times but never faced problem. Yesterday I was dealing with Fragments which I am not too familiar with but implemented successfully. But at the end of the day when I included seekbar to the fragment and problems started. Not sure this is coz of fragments or what. Here is my code.

fragment_main.xml

<LinearLayout>
<SeekBar
    android:id="@+id/seek"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:max="100"/>
</LinearLayout>

FragmentMain.java

public class FragmentMain extends Fragment {

final static String TAG = "FragmentMain";
TextView mainTextView;

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

    SeekBar seekBar = (SeekBar) getActivity().findViewById(R.id.seek);
    seekBar.setProgress(40);

    return view;
}
}

This FragmenMain is the center page of my viewPager.

I dont know why my code is crashing giving NullPointerException at setProgress.

Feel free to suggest edits.

The question has been marked duplicate comparing it with a question with a very broad aspect. I obviously know what nullPointerException means. I was not able to spot it here. Comeon! @Blackbelt — Srujan Barai, May 14 '16 at 02:36
That's the question I use for every NPE related questions. I could I agree on the fact that's slightly different in your case, but really your fragment related NPE question has been asked over and over again in the past. When you get a null reference from findViewById, it is always because you are looking for it in the wrong place — Blackbelt, May 14 '16 at 06:45

score 1 · Answer 1 · answered May 10 '16 at 10:44

1

Change

SeekBar seekBar = (SeekBar) getActivity().findViewById(R.id.seek);

to

SeekBar seekBar = (SeekBar) view.findViewById(R.id.seek);

answered May 10 '16 at 10:44

Linh

57,942
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Hey thanks it worked. Can you explain why context didn't work? – Srujan Barai May 10 '16 at 10:52

score 1 · Accepted Answer · answered May 10 '16 at 10:45

1

The problem is here

SeekBar seekBar = (SeekBar) getActivity().findViewById(R.id.seek);

You need to find the view with the parent view which your inflating not with context, replace it with

SeekBar seekBar = (SeekBar) view.findViewById(R.id.seek);

Hope it helps

answered May 10 '16 at 10:45

Atiq

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Hey thanks it worked. Can you explain why context didn't work? – Srujan Barai May 10 '16 at 10:52
1

because your inflating you layout with view, so it has the access to the contents of the layout, in fragments you will always find the views with the view your inflating your layout – Atiq May 10 '16 at 10:57
Ok. I tried getActivity() with a Toast and that worked. – Srujan Barai May 10 '16 at 10:59
you will always use context with toast, after this line `View view = inflater.inflate(R.layout.fragment_main, container, false);` view contains all the views inside that layout so you need to access them with view – Atiq May 10 '16 at 11:21
Gottcha! Thanks for clearing it – Srujan Barai May 10 '16 at 11:22
glad I could help :) – Atiq May 10 '16 at 11:24

Android: seekbar.setProgress() gives Nullpointer exception

2 Answers2