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Is there any method after creating the view of fragments?How to change Layout of tabs after creating fragments

I need to call a method in which I parse the JSON objects and set the values I sets values in TextFields and button values, I created fragments but after creating the fragments how will I change the text field values
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
TextView textView = (TextView) rootView.findViewById(R.id.section_label);
textView.setText(getString(R.string.section_format, getArguments().getInt(ARG_SECTION_NUMBER)));
//Switch to different layout accordingly
switch (getArguments().getInt(ARG_SECTION_NUMBER))
{
case 1: {
rootView = inflater.inflate(R.layout.fragment_main, container, false);
break;
}
case 2: {
rootView = inflater.inflate(R.layout.fragment_receipt, container, false);
break;
}
case 3: {
rootView = inflater.inflate(R.layout.fragment_totals, container, false);
break;
}
case 4: {
rootView = inflater.inflate(R.layout.fragment_keyboard, container, false);
break;
}
case 5: {
rootView = inflater.inflate(R.layout.fragment_keylock, container, false);
break;
}
}
return rootView;
}
}
I tried to call the method in onStart but onStart method is been called first before the onCreateView and hence I get null pointer exception when I am assigning the value :
#Override
public void onStart() {
super.onStart();
parseJsonResponse(response_message);
}
In the parseJsonResponse() method, I sets the value
String UIFooter = ResponseHeaderObject.getString("FOOTER");
//Set Header Display
headerTextView =(TextView) findViewById(R.id.headerTextView);
headerTextView.setText(UIHeader);
here is the error from logcat:
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
at com.mpos.kits.smartpos.PosMainActivity.parseJsonResponse(PosMainActivity.java:366)

Fragments have a function named: onViewCreated which called after your view was created

Yes, that method exists: onViewCreated. however, if you want to assign a text to the TextView outside the method on which it has been created, you have to declare the TextView as a member property (outside any method), to allow its use by all class methods. Otherwise, within a fragment, it will be difficult to manipulate it.
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference at com.mpos.kits.smartpos.PosMainActivity.parseJsonResponse(PosMainActivity.java:366)
You are getting this error because this headerTextView =(TextView) findViewById(R.id.headerTextView); returns null in your fragment unless it's referred to a root view like in the onCreateView method. this way (TextView) rootView.findViewById(R.id.section_label);
If you want to override onViewCreated method, do it this way:
#Override
public void onViewCreated(#NonNull View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
//your code
}

.getView.findViewById in fragment returning NullPointerException [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);
}

Cannot retrieve View in onResume() method inside Fragment

I have a method in my fragment that I would like to call from onResume(). Unfortunately, my method requires that I pass it a View, which is defined in onCreateView():
onResume():
#Override
public void onResume() {
super.onResume();
retrieveData(0, false, rootView);
}
onCreateView():
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
// Set view
View rootView = inflater.inflate(R.layout.tab_fragment_1, container, false);
...
}
Is there a way to call my retrieveData method as is in onResume(), or should I just create a new method without the rootView parameter (not ideal)?
Can't move it to global scope because the inflater method parameter is part of the fragment interface.

You can only get the view from your fragment, not your activity. To do this, in your fragment onCreateView
save the root view as an Instance Variable like
private View root;
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
root = inflater.inflate(R.layout.fragment_details_buddy, container, false);
... }
And call it in your onResume
Edit : to get data from Activity, pass it in a Bundle. Doc

Unfortunately, app has stopped,how can I make this work onCreateView?

Previously, I had a similar issue, app crashes when trying to access (or findByID), it turned out, I've put the textview in the wrong method, Now I have only one method, and I am working with a fragment, the method onCreateView and my app keeps crashing:
public class InfoFragment extends Fragment {
public InfoFragment() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
TextView n = (TextView) getView().findViewById(R.id.nama);
n.setText("Some String");
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_info, container, false);
}
}
Originally, I had the line looking like this :
TextView n = (TextView) findViewById(R.id.nama);
However,the compiler gave me an error saying it can't find the method findViewById, so some research showed that I should add getView() , I did, and the error disappeared, but now the app is crashing, any ideas?

#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_info, container, false);
TextView n = (TextView) view.findViewById(R.id.nama);
n.setText("Some String");
return view;
}
You don't have a view yet in that part of code. Inflate it first and use after.

Inflate your layout first, then you can use it to find the TextView:
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_info, container, false);
TextView n = (TextView) rootView.findViewById(R.id.nama);
n.setText("Some String");
return rootView;
}

Adding calculator to navigation drawer

I've got a problem. For school project I have to create app in Android Studio with few activities so i decided to add Navigation Drawer, but when i try to create simple calculator to app i can't even reference button or textview. This is code for activity where I want to create calculator. Also I have to add Map Activity and SQLite Database.
public class Calculator_main extends Fragment {
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootview = inflater.inflate(R.layout.calculator, container, false);
return rootview;
}
}

Use rootView to find your item when referencing in a Fragment:
public class Calculator_main extends Fragment {
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootview = inflater.inflate(R.layout.calculator, container, false);
//Notice the TextView being referenced with rootView in front of the findViewById statement
TextView namefield = (TextView) rootView.findViewById(R.id.namefield);
return rootview;
}
}
You need to do this when using Fragment, as this is the only way your app can reference an item in your Fragment's XML view
This is however not necessary in an Activity and should not be confused with the method of referencing in a Fragment