findViewById in Fragment

Question

I am trying to create an ImageView in a Fragment which will refer to the ImageView element which I have created in the XML for the Fragment. However, the findViewById method only works if I extend an Activity class. Is there anyway of which I can use it in Fragment as well?

public class TestClass extends Fragment {
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        ImageView imageView = (ImageView)findViewById(R.id.my_image);
        return inflater.inflate(R.layout.testclassfragment, container, false);
    }
}

The findViewById method has an error on it which states that the method is undefined.

Solution 1

Use getView() or the View parameter from implementing the onViewCreated method. It returns the root view for the fragment (the one returned by onCreateView() method). With this you can call findViewById().

@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
    ImageView imageView = (ImageView) getView().findViewById(R.id.foo);
    // or  (ImageView) view.findViewById(R.id.foo); 

As getView() works only after onCreateView(), you can't use it inside onCreate() or onCreateView() methods of the fragment .

Solution 2

You need to inflate the Fragment's view and call findViewById() on the View it returns.

public View onCreateView(LayoutInflater inflater, 
                         ViewGroup container, 
                         Bundle savedInstanceState) {
     View view = inflater.inflate(R.layout.testclassfragment, container, false);
     ImageView imageView = (ImageView) view.findViewById(R.id.my_image);
     return view;
}

Solution 3

Inside Fragment class you will get onViewCreated() override method where you should always initialize your views as in this method you get view object using which you can find your views like :

@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
    view.findViewById(R.id.yourId).setOnClickListener(this);

    // or
    getActivity().findViewById(R.id.yourId).setOnClickListener(this);
}

Always remember in case of Fragment that onViewCreated() method will not called automatically if you are returning null or super.onCreateView() from onCreateView() method. It will be called by default in case of ListFragment as ListFragment return FrameLayout by default.

Note: you can get the fragment view anywhere in the class by using getView() once onCreateView() has been executed successfully. i.e.

getView().findViewById("your view id");

Solution 4

I realise this is an old question, but the prevailing answer leaves something to be desired.

The question is not clear what is required of imageView - are we passing it back as the view, or merely saving a reference for later?

Either way, if the ImageView is coming from the inflated layout, the correct way to do this would be:

public class TestClass extends Fragment {
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.testclassfragment, container, false);
        ImageView imageView = (ImageView)v.findViewById(R.id.my_image);
        return v;
    }
}

Solution 5

Get first the fragment view and then get from this view your ImageView.

public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.testclassfragment, container, false);
    ImageView imageView = (ImageView) view.findViewById(R.id.my_image);
    return view;
}

View more solutions

Comments

[Shomu]

Use ButterKnife viewbinding library for android. Also demonstrate how it’s work, how to integrate and use in your android app development to make your development faster.

[David3103]

'Some' time has passed but you still haven't accepted an answer. Can you select the answer that helped you most so this can be marked as answered?

[mochadwi]

It is encourages to use Data Binding orang View Binding instead manual findViewById

[Tsunaze]

So, does onCreate method is useful in a Fragment ?

[xevincent]

onCreateView creates and returns the view hierarchy associated with the fragment.onCreate is called to do initial creation of the fragment. Indeed, it depends on what you write in these methods.

[Tsunaze]

Okay, but how can i declare variable in the onCreate ? Because the View is inside the onCreateView method .

[Raunak]

When you do V.findViewById(R.id.someid),surely that will only work for all the widgets that are in the inflated view. What if the imageView he is trying to inflate is outside the inflated view?

[LeffelMania]

Then the class that "owns" and inflated the imageView needs to provide public access to it. That is very bad practice though. Fragments should only have access to the UI elements present in their layout.

[Dmitry Zaytsev]

Note: it's works only after onCreateView(). So, you can't use this in onCreate()

[StuStirling]

@Tsunaze did you ever find out how to do this from the onCreate method?

[Nico AD]

so what is the function I can override to implement this if onCreate is not the right place ?

[MattJenko]

This doesn't help if the ImageView is coming from the inflated layout - see my answer for details. Otherwise, onCreateView is the right place to do this @N-AccessDev

[whyoz]

How then would you update imageView from ListFragment? Would this require FragmentManager? In other words, how can you update the imageView in a detail fragment from a separate class's onListItemClick?

[advantej]

The best place to do this the onViewCreated method

[Steve M]

the view is not the activity

[MattJenko]

You would either save a reference to the imageView somewhere handy, or fragment.getView().findViewById(R.id.my_image) when you need it. In a ListFragment, assuming the image is in a list item, you would generally create a reference holder with the setTag/getTag methods of the list view item in your Adapter's getView method - there are many examples of how to do this.

[Jon]

you can't use getActivity and findViewById there in onCreate() or onCreateView either because they both come before onActivityCreated() which is when you are guaranteed that the activity view heirarchy has been created.

[fransre]

Note that findViewById has to be called on the view that is inflated, not on getView()

[Monstieur]

The documentation states that onActivityCreated() is the recommended place to find and store references to your views. You must clean up these stored references by setting them back to null in onDestroyView() or you will leak the Activity.

[MrAsterisco]

For future readers: this method does not work. It just raises a android.view.ViewRootImpl$CalledFromWrongThreadException.

[LeffelMania]

Looks like there's something wrong in your code (updating UI from a background thread), not mine.

[Sonny]

I am surprised not a lot of people have upvoted this response--this is the correct way to setup listeners on fragments... Perhaps this was a new development in the API.

[altumano]

Thanks, it was useful. As unrelated comment: try to stick to Java naming conventions in your code. "V" does not look like a variable name in Java.

[Mike Brian Olivera]

i thinked this could be posiible, but , it didn't work

[Redoman]

It works but I don't get why: I understand that findViewById() works in the scope of an Activity object because it is defined in the Activity class. As explained in this answer, in order to use it in a fragment we need to call it on getView() but... why? Isn't getView() just going to return a View as opposed to an Activity? ... I understand getActivity.findViewById() but getView.findViewById() ???

[Machado]

This should be the right answer. The accepted one leaves you with NullPointerException.

[Confuse]

getView might return null. LeffelMania has a better solution.

[Dmitry]

Using view passed to onViewCreated still causes NullPointerException but using getActivity() is fine. Any ideas why?

[Ankur Chaudhary]

@dVaffection It may be that you are not returning a non null view in onCreateView() lifecycle method of fragment. Now in case of getActivity you are getting views from your activity rather than fragment main view depends upon what id you are passing. Please check are you returning a non null view from onCreateView or not? Then let me know.

[Dmitry]

@AnkurChaudhary I return view from onCreateView method. I've just debugged and it turns out there is a layout (in my case FrameLayout). That being said when I try to find an element it returns null. Why is it happening?

[Ankur Chaudhary]

@dVaffection can you please share your class of fragment and corresponding layout.

[Dmitry]

@AnkurChaudhary You can find it here github.com/dVaffection/YAGL/tree/master/app/src/main/java/co‌​m/…

[Dmitry]

In particular ListActivityFragment.java line 63 (FloatingActionButton) getActivity().findViewById(R.id.floating_new_item);

[Ankur Chaudhary]

@dVaffection i have gone through your code and as you are returning super.oncreateView() which returns null. Another point is when you return null from onCreateView, onViewCreated() method will not be called automatically. Yes you can call it manually. Means onViewCreated will not be called if you are returning null or super method calling. That's why when you are trying to get any view from fragment it's returning null to you.

[Dmitry]

@AnkurChaudhary What you're saying is valid if you inherit from Fragment, in my case I extend ListFragment which actually returns FrameLayout.

[Ankur Chaudhary]

@dVaffection I checked the layout that ListFragment is using and there is no such view with the id 'floating_new_item'. So it's pretty clear that if you will try to access such field which is not in your layout then it'll return null. Now let me know that is your activity having this id field or not as you are using fragment_list layout in your activity.

[George]

This should be the most voted, since is the correct answer. The one by advantej is wrong, since the layout hasn't been inflated before the getView()

[Reti43]

This is identical to LeffelMania's answer.

[Aleksey Khivrenko]

@Raunak You are correct inflater.inflate(R.layout.yourdialogfragment, null).findViewById(R.id.someidfromfragmentdialog) will only return widgets that are in the fragment. If you want to get widgets from the host activity (the activity that spawned the DialogFragment) you have to use getActivity().findViewById(R.id.someidfromhostlayout)

[Muhammad Babar]

@Locutus You must clean up these stored references by setting them back to null in onDestroyView() or you will leak the Activity reference please?

[Amit]

Why down voted, if you use this, you can use multiple onclicks also in on statement.

[Boris Karloff]

I agree. This answer should be marked as the solution.

[KMC]

@Raunak Thanks for the comment. I was wondering out aloud why the accepted answer does not use the view returned by the inflater. This discussion has clarified my doubt.

[OneCricketeer]

1) What does this add to other answers? 2) You seem to have answered twice

[OneCricketeer]

There's no reason for the field. You can always call getView() later

[Bipin Bharti]

@cricket_007 getview work in onCreateview() in fragment

[OneCricketeer]

@RobbyPatel There's no possible way it can. It will return null.

[Bipin Bharti]

@cricket_007 here is another issue my code is completely good

[OneCricketeer]

Yes, this code here is okay. Your edits to the other are not.

[Bipin Bharti]

@cricket_007 ok which one can you saw me?

[OneCricketeer]

I'm sorry I can't quite understand your English, but everything is fixed now. I have nothing to show you.

[Pulak]

Actually you can make it work inside onCreateView() if you capture the view instance as View rootView = inflater.inflate(R.layout.your_fragment_layout, container, false); and do rootView.findViewById() after that

[OneCricketeer]

@NoLuck, Yes, but that's what the other answers are for

[Shaurya Uppal]

Without casting thing explained helped me.

[Hendy Irawan]

@MuhammadBabar reference: developer.android.com/reference/android/app/Fragment.html

[user3294126]

What if part of creating my Activity (onCreate()) that contains my Fragment depends on the UI elements of the Fragment? Where can I initialize my Fragment's views so that they are initialized after the Fragment has been committed but before the Activity's onCreate() is finished? Or instead should I be initializing my Activity's UI in a method after onCreate(), like onResume()?

[pintergabor]

Casting to ImageView is redundant.

[Benjamin Kershner]

Good information on the difference between onViewCreated and onCreateView here: stackoverflow.com/a/38718205/7715734

[Pranav Kasetti]

I would recommend using view.findViewById since this has a built-in NonNull annotation, thus no warnings to handle null pointer exceptions

[Moeez]

mine giving null. I have posted a new question

[HX_unbanned]

@MattJenko, can you share more details or sample how to do have working solution when the inflated layout is used? for instance, i have an viewpager2 with tablayout (4 tabs ) mediated, and I am inflating the edittext views in fragment, and I need to access the editext for each viewpager2's view from main activity. How to do it exactly?

[HX_unbanned]

Note that API 28 introduces requiereActivity(), requireView(), requireViewById().

[HX_unbanned]

I suggest to combine this answer with one mentioning deprecation of getView() in API 28.