findViewById in Fragment
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.
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 .
你需要膨胀Fragment的视图并在它返回的View
上调用findViewById()
。
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;
}
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. ie
getView().findViewById("your view id");
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