InjectView in RoboFragment - android

I want to inject some views from an xml layout to a RoboFragment but unfortunately I am getting Nullpointer Exception. Since RoboGuice (besides being a great DI framework) has very little documentation, I don't know if I can use #ContentView(R.layout.fragmentlayout) to annotate my RoboFragment. Is there something I should do instead? What I currently do is:
public class TestFragment extends RoboFragment {
#InjectView(R.id.upBtn) private Button upBtn;
#Override
public View onCreateView(LayoutInflater layoutInflater,
ViewGroup container, Bundle savedInstanceState) {
super.onCreateView(layoutInflater, container, savedInstanceState);
View view = layoutInflater.inflate(R.layout.fragmentlayout, container, false);
RoboGuice.getInjector(getActivity()).injectMembers(this);
upBtn.setSelected(false); // <------ Null pointer here
return view;
}
}


If you look at the source for RoboFragment, you'll see
#Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
RoboGuice.getInjector(getActivity()).injectViewMembers(this);
}
If you insist on injecting manually, use injectViewMembers(). If you can delay touching the view until after onViewCreated(), then it will be set up for you.


You need to return view. After upBtn.setSelected(false);
public View onCreateView(LayoutInflater layoutInflater, ViewGroup container, Bundle savedInstanceState) {
super.onCreateView(layoutInflater, container, savedInstanceState);
View view = layoutInflater.inflate(R.layout.fragmentlayout, container, false);
RoboGuice.getInjector(getActivity()).injectMembers(this);
upBtn = (Button) view.findViewById(YOUR_ID); // Initialization
upBtn.setSelected(false); // <------ Null pointer here
return view;
}

Related

Cannot resolve symbol in Inflater in findViewById [duplicate]

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 .

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;
}

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");

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;
}
}

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;
}

Inside Fragment class we get onViewCreated() override method where we should always initialize our views because in this method we get view object. Using this object we can find our views like below:
class MyFragment extends Fragment {
private ImageView imageView;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.my_fragment_layout, container, false);
}
#Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
//initialize your view here for use view.findViewById("your view id")
imageView = (ImageView) view.findViewById(R.id.my_image);
}
}

You could also do it in the onActivityCreated Method.
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
}
Like they do here: http://developer.android.com/reference/android/app/Fragment.html (deprecated in API level 28)
getView().findViewById(R.id.foo);
and
getActivity().findViewById(R.id.foo);
are possible.

getView() will give the root view
View v = getView().findViewByID(R.id.x);

You can override onViewCreated() which is called right after all views had been inflated. It's the right place to fill in your Fragment's member View variables. Here's an example:
class GalleryFragment extends Fragment {
private Gallery gallery;
(...)
#Override
public void onViewCreated(View view, Bundle savedInstanceState) {
gallery = (Gallery) view.findViewById(R.id.gallery);
gallery.setAdapter(adapter);
super.onViewCreated(view, savedInstanceState);
}
}

The method getView() wont work on fragments outside OnCreate and similar methods.
You have two ways, pass the view to the function on the oncreate (what means you can only run your functions when the view is being created) or set the view as a variable:
private View rootView;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
rootView = inflater.inflate(R.layout.fragment_contatos, container, false);
}
public void doSomething () {
ImageView thumbnail = (ImageView) rootView.findViewById(R.id.someId);
}

1) first inflate layout of Fragment then you can use findviewbyId .
View view = inflater.inflate(R.layout.testclassfragment, container, false);
ImageView imageView = (ImageView) view.findViewById(R.id.my_image);
return view;

EditText name = (EditText) getView().findViewById(R.id.editText1);
EditText add = (EditText) getView().findViewById(R.id.editText2);

agreed with calling findViewById() on the View.
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;
}

Note :
From API Level 26, you also don't need to specifically cast the result of findViewById as it uses inference for its return type.
So now you can simply do,
public View onCreateView(LayoutInflater inflater,
ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.testclassfragment, container, false);
ImageView imageView = view.findViewById(R.id.my_image); //without casting the return type
return view;
}

Use
imagebutton = (ImageButton) getActivity().findViewById(R.id.imagebutton1);
imageview = (ImageView) getActivity().findViewById(R.id.imageview1);
it will work

According to the documentation on API level 11
Reference, in Back Stack
http://developer.android.com/reference/android/app/Fragment.html
short code
/**
* The Fragment's UI is just a simple text view showing its
* instance number.
*/
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.hello_world, container, false);
View tv = v.findViewById(R.id.text);
((TextView)tv).setText("Fragment #" + mNum);
tv.setBackgroundDrawable(getResources().getDrawable(android.R.drawable.gallery_thumb));
return v;
}

Using getView() returns the view of the fragment, then you can call findViewById() to access any view element in the fragment view.

Try this it works for me
public class TestClass extends Fragment {
private ImageView imageView;
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.testclassfragment, container, false);
findViews(view);
return view;
}
private void findViews(View view) {
imageView = (ImageView) view.findViewById(R.id.my_image);
}
}

1) Declare your layout file.
public View onCreateView(LayoutInflater inflater,ViewGroup container,
Bundle savedInstanceState) {
return inflate(R.layout.myfragment, container, false);
}
2)Then, get the id of your view
#Override
public void onViewCreated(View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
TextView nameView = (TextView) view.findViewById(R.id.textview1);
}

The best way to implement this is as follows:
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
rootView = inflater.inflate(R.layout.testclassfragment, container, false);
ImageView imageView = (ImageView) rootView.findViewById(R.id.my_image);
return rootView
}
In this way, the rootView can be used for each control defined in the xml layout and the code is much cleaner in this way.
Hope this helps :)

Try This:
View v = inflater.inflate(R.layout.testclassfragment, container, false);
ImageView img = (ImageView) v.findViewById(R.id.my_image);
return v;

try
private View myFragmentView;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
myFragmentView = inflater.inflate(R.layout.myLayoutId, container, false);
myView = myFragmentView.findViewById(R.id.myIdTag)
return myFragmentView;
}

Use gradle skeleton plugin, it will automatically generate the view holder classes with the reference to your layout.
public class TestClass extends Fragment {
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
MyLayout myLayout = new MyLayout(inflater, container, false);
myLayout.myImage.setImageResource(R.drawable.myImage);
return myLayout.view;
}
}
Now assuming you had an ImageView declared in your my_layout.xml file, it will automatically generate myLayout class for you.

I like everything to be structured. You can do in this way.
First initialize view
private ImageView imageView;
Then override OnViewCreated
#Override
public void onViewCreated(View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
findViews(view);
}
Then add a void method to find views
private void findViews(View v) {
imageView = v.findViewById(R.id.img);
}

//here you can do it by
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState)
{
// Inflate the layout for this fragment
final View view = inflater.inflate(R.layout.fragment_apple, container,
false);
ist = view.findViewById(R.id.linearLink);
second = view.findViewById(R.id.linearPhone);
return view;

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

You can call findViewById() with the Activity Object you get inside your public void onAttach(Activity activity) method inside your Fragment.
Save the Activity into a variable for example:
In the Fragment class:
private Activity mainActivity;
In the onAttach() method:
this.mainActivity=activity;
Finally execute every findViewById through the vairable:
mainActivity.findViewById(R.id.TextView);

Inside onCreateView method
1) first you have to inflate the layout/view you want to add
eg. LinearLayout
LinearLayout ll = inflater.inflate(R.layout.testclassfragment, container, false);
2) Then you can find your imageView id from layout
ImageView imageView = (ImageView)ll.findViewById(R.id.my_image);
3)return the inflated layout
return ll;

You have to inflate the view
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
}}

There is one more method called onViewCreated.
#Override
public void onViewCreated(View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
ImageView imageView = (ImageView) view.findViewById(R.id.imageview1);
}

Using findViewById inside a Fragment

I am creating a new Tab interface and for every tab I have functionality like:
public class ClassViewFragment extends Fragment {
ListView classListView = null;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.class_view, container, false);
classListView = (ListView) findViewById(R.id.classList);
return rootView;
}
}
But I am getting cannot resolve method findViewById also at another place I am also unable to use runOnUiThread and getting Error:(88, 29) error: cannot find symbol method runOnUiThread(<anonymous Runnable>)
I understand these will work fine if my class was extended from Activity but it’s a tab fragment so how can I use this funcitons?

you need
classListView = (ListView) rootView.findViewById(R.id.classList);
as that is the view you are concerned with
to get runOnUiThred you need to do getActivity().runOnUiThread

You need to reference findViewById using the view,
public class ClassViewFragment extends Fragment {
ListView classListView = null;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.class_view, container, false);
classListView = (ListView) rootView .findViewById(R.id.classList);
return rootView;
}
}
For runOnUiThread is a possible duplicate of Modifying an Android view from a different thread
use its like,
activity.runOnUiThread(new Runnable());

Here is a shore explanation of findViewById method;
findViewById() method will work with the related object that your main layout is bound to. For example, In an activity, when you make a
setContentView(activity_main);
You imply that your Activity will retrieve its layouts from activity_main. So when you make a findViewById() in an activity, that actually means this.findViewById(), where this is your Activity.
So in your case, the layout class_view is bound to the rootView. But when you just write findViewById, it means that this.findViewById. And this is the scope you're in, which is the Fragment in your case. However, I don't think a Fragment has that capability. So you should refer to the rootView to retrieve your views.
rootView.findViewById()

Fragments don't have a findViewById() method like Activity, so you have to call the method of the root view of the fragment. Try doing rootView.findViewById(R.id.classList) instead.

#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_content_mediaplayer, container, false);
mSeekbar = (SeekBar) v.findViewById(R.id.seekBarMusic);
return v;

Use rootView.findViewById(R.id.classList) instead of findViewById(R.id.classList).
Try this:
public class ClassViewFragment extends Fragment {
ListView classListView = null;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.class_view, container, false);
classListView = (ListView) rootView.findViewById(R.id.classList);
return rootView;
}
}

findViewById must run inside onViewCreated() method
ListView classListView = null;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
return inflater.inflate(R.layout.class_view, container, false);
}
#Override
public void onViewCreated(View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
classListView = (ListView) view.findViewById(R.id.classList);
}
}`

Detecting the right View

I need a little bit help, defining my in event_filter.xml declared Views.
It is an child of an AbstractDetailListFragment and implements a DatePicker and a Spinner item.
But I dont know how to acces them in an AbstractDetailFragment.
By defining
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View theView = super.onCreateView(inflater, container, savedInstanceState);
ImageButton searchEnterButton = (ImageButton)getNavigationFragment().getNavigationBar().getRightButton();
View view = getView();
final DatePicker datePicker = (DatePicker) container.findViewById(R.id.datePickerEvent);
Spinner inSpinner = (Spinner) container.findViewById(R.id.category_list);
spinner = inSpinner;
downloadCategories();
the variables view, datePicker, inSpinner always are null!
Any Ideas?
thanks a lot.

That's a thing about fragments. I've been looking for the same error for days, until I read a little bit about fragments (i was lazy and i recommend you not to follow my footsteps ). The way i solved it was by overriding onViewCreated and "catching" views there:
public class MyFragment extends Fragment {
View rootView;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
rootView = inflater.inflate(R.layout.my_fragment, container,
false);
return rootView;
}
//and you use rootView to call findViewById
#Override
public void onViewCreated(View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
Button myButton = (Button) rootView.findViewById(R.id.mybutton);
sendFeedback.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
//do something
}
});
}
}

How to access a UI element in a fragment?

I have a fragment with a control (a TextView) with id R.id.currentCycleIndicator and want to programmatically set its value from within the fragment.
Both
getActivity().findViewById(R.id.currentCycleIndicator) and
getView().findViewById(R.id.currentCycleIndicator)
return null.
How can I get reference to that TextView inside the fragment code?

Try getting its value in onCreateView() callBack function of your Fragment like below :
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_layout, container, false);
TextView textView = (TextView) view.findViewById(R.id.currentCycleIndicator);
return view;
}

You can do that by overriding the onViewCreated function as below :
private TextView tv;
#Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
tv = (TextView) view.findViewById(R.id.currentCycleIndicator);
}

Inflate your view inside onCreateView and refer to your TextView from there.
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.layoutwheretextviewis, container, false);
TextView text= (TextView) view.findViewById(R.id.currentCycleIndicator);
return view;
}

Android - Add code to a fragment

I am a beginner in coding for Android and i am trying to do an application with two fragments. Unfortunately, when i add code to set action to my layout, it makes my application crash, so i'm wondering where i should put my code on the fragment file. If i take out the function onCreate, the application doesn't crash and my layout is good.
Here is my code. Thank you so much for your answer.
public class FragmentOne extends Fragment{
public static final String TAG = "FragmentOne";
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = View.inflate(getActivity(), R.layout.fragmentone, null);
return v;
}
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
final EditText etData = (EditText) getView().findViewById(R.id.etData);
}
}

First of all I can see a few mistakes in your code.First of all as #user1873880 mentioned, onCreate() is always called before onCreateView(), so you should consider dealing with your views in onCreateView(). Second mistake which I can see is that you are not creating your View as it's designed to be used on Fragment. In my opinion the way your Fragment should look is like this :
public class FragmentOne extends Fragment {
private static final String TAG = "FragmentOne";
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
super.onCreateView(inflater, container, savedInstanceState);
// create your view using LayoutInflater
return inflater.inflate(R.layout.fragmentone, container, false);
}
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// do your variables initialisations here except Views!!!
}
public void onViewCreated(View view, Bundle savedInstanceState){
super.onViewCreated(view, savedInstanceState);
// initialise your views
EditText etData = (EditText) view.findViewById(R.id.etData);
}
}
Hope this helps you! : )

The reason is that onCreate is invoked before onCreateView, so you can manipulate with your views only after onCreateView callback. For more information check Fragment lifecycle here.

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