NullPointerException on ImageView in Fragment in FragmentPagerAdapter

Question

I have a bunch of fragments in a FragmentPagerAdapter with one ImageView in side each fragment. If I swipe really fast this error comes up:

E/AndroidRuntime: FATAL EXCEPTION: main
                Process: com.wilsapp.wilsapp, PID: 21319
                java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.View android.view.View.findViewById(int)' on a null object reference
                at com.wilsapp.wilsapp.Fragments.BuyerHomePageFragment9$DownloadImageTask.onPostExecute(BuyerHomePageFragment9.java:212)
                at com.wilsapp.wilsapp.Fragments.BuyerHomePageFragment9$DownloadImageTask.onPostExecute(BuyerHomePageFragment9.java:192)
                at android.os.AsyncTask.finish(AsyncTask.java:651)
                at android.os.AsyncTask.-wrap1(AsyncTask.java)
                at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:668)
                at android.os.Handler.dispatchMessage(Handler.java:102)
                at android.os.Looper.loop(Looper.java:148)
                at android.app.ActivityThread.main(ActivityThread.java:5417)
                at java.lang.reflect.Method.invoke(Native Method)
                at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
                at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

If I swipe slowly then it works perfectly fine.

Android Code (code is the same for each fragment. Code in AsyncTask):

   protected void onPostExecute(Bitmap result) {
    try {
        ImageView img = (ImageView) getView().findViewById(R.id.ProductOneImageView);
        img.setImageBitmap(result);
    }catch (Exception e){
        ImageView img = (ImageView) getView().findViewById(R.id.ProductOneImageView);
        int id = getResources().getIdentifier("com.wilsapp.wilsapp:drawable/" + "error", null, null);
        img.setImageResource(id);
    }
}

Android onCreatView method:

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {

    View view = inflater.inflate(R.layout.fragment_buyer_home_page, container, false);

    return view;
}

how can i avoid the NullPointerException?

Hi Make sure your findViewByIdonly called when the view is created otherwise it throw null pointer exception because they could not able to find the id inside the fragment — Bhavdip Sagar, May 12 '16 at 05:43
Here is the same problem and solutions http://stackoverflow.com/questions/37177999/java-lang-nullpointerexception-attempt-to-invoke-virtual-method-android-view-v — Sergey Chechenev, May 12 '16 at 05:55
@sushildlh still tells me that NullPointerException may happen — Lazar Kukolj, May 12 '16 at 21:48
@RajenRaiyarela still tells me that NullPointerException may happen — Lazar Kukolj, May 12 '16 at 21:48
that try catch is in the 'onPostExecute' method in a 'AsyncTask' — Lazar Kukolj, May 12 '16 at 21:50
@LazarK after `View view = inflater.inflate(R.layout.fragment_buyer_home_page, container, false);` you have to put your code for initializing `ImageView img = (ImageView) getView().findViewById(R.id.ProductOneImageView);`. Declare ImageView img so is available to internal classes. — Rajen Raiyarela, May 13 '16 at 05:46
@RajenRaiyarela remove the getView() and add view and then it works ;) — Lazar Kukolj, May 14 '16 at 19:15

score 0 · Answer 1 · answered May 12 '16 at 06:19

0

ImageView img = (ImageView) getView().findViewById(R.id.ProductFiveImageView);

ImageView need initialize in onCreateView. A case of you getView() return null...

answered May 12 '16 at 06:19

PeDuCKA

553
3
13

score 0 · Answer 2 · answered May 12 '16 at 06:26

0

Add your initialization snippet in onViewCreated method instead of onCreateView. it will ensure that imageview will be initialize after your view is inflated.

@Override
    public void onViewCreated(final View view, @Nullable Bundle savedInstanceState) {

 ImageView img = (ImageView) view.findViewById(R.id.ProductFiveImageView);
            img.setImageBitmap(result);

}

answered May 12 '16 at 06:26

KDeogharkar

10,939
7
51
95

what if i use a 'onCreateView' method? – Lazar Kukolj May 12 '16 at 21:46
if you change the method to mine then I'll mark it correct – Lazar Kukolj May 13 '16 at 02:02
I dont know what is issue with this method? you can use it if it will resolve your issue.`onViewCreated` will call after your view is created so your view will never null if this method getting call if you inflate view properly . so give it a try @LazarK – KDeogharkar May 13 '16 at 04:50
because it isnt the method i used in my problem? – Lazar Kukolj May 14 '16 at 19:18

score 0 · Answer 3 · edited Jul 20 '16 at 11:52

0

ImageView img = (ImageView) getView().findViewById(R.id.ProductFiveImageView);

hi You can add a judgment,getView Whether to null， and Fault tolerant processing!

edited Jul 20 '16 at 11:52

Harshad Pansuriya

20,189
8
67
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answered May 12 '16 at 06:28

kabuqinuofu

1

what this made no sense? – Lazar Kukolj May 12 '16 at 21:45
Because I think the problem is in getView() return null , And then make a judgment. – kabuqinuofu May 13 '16 at 01:03
Example ： if( getView() != null){ImageView img = (ImageView) getView().findViewById(R.id.ProductFiveImageView);} – kabuqinuofu May 13 '16 at 01:08
Your question is this every time? Because I have encountered similar problems, is to make a judgment to solve the problem, if you do not solve your problem is very sorry! – kabuqinuofu May 13 '16 at 01:16

NullPointerException on ImageView in Fragment in FragmentPagerAdapter

3 Answers3