setBackgroundDrawable give nullpointerexception in android - java

I am trying to create a circle inside a fragment and I need to change its color in runtime in future.
but the method setBackgroundDrawable gives me nullPointerException.
I am not able to figure it out as I am web developer and I am new to android development. Please help me.
And the code is below
public class tester extends Fragment {
private View circle_holder;
#SuppressWarnings("deprecation")
#SuppressLint("NewApi")
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.today, container, false);
circle_holder = (View)getActivity().findViewById(R.id.cicle);
ShapeDrawable mDrawable = new ShapeDrawable(new OvalShape());
mDrawable.getPaint().setColor(Color.RED);
if (Build.VERSION.SDK_INT >= 16){
circle_holder.setBackground(mDrawable);
}
else{
circle_holder.setBackgroundDrawable(mDrawable);
}
return rootView;
}
}

Change this line.
circle_holder = (View)getActivity().findViewById(R.id.cicle);
into
circle_holder = (View)rootView .findViewById(R.id.cicle);

Related

.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);
}

Error in my Fragment Class missing return statement

This is my YoutubeFragment.java
public class YoutubeFragment extends Fragment {
private static final String[] YOUTUBE_PLAYLISTS = {
"PLpzzpBegb_9o6SkHEMbF5bcQYzxOARrAY",
"PLWz5rJ2EKKc_Tt7q77qwyKRgytF1RzRx8",
};
private YouTube mYoutubeDataApi;
private final GsonFactory mJsonFactory = new GsonFactory();
private final HttpTransport mTransport = AndroidHttp.newCompatibleTransport();
View myView;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
myView = inflater.inflate(R.layout.youtube_activity, container, false);
if (CheckNetwork.isInternetAvailable(getActivity().getApplicationContext())){
return myView;
}else showNetDisabledAlertToUser(getActivity().getApplicationContext());
} //error here
}
Getting error at second last '}' syaing missing return satement. What am I doing wrong
You should return your View below
if (CheckNetwork.isInternetAvailable(getActivity()))
{ // Do your work
}else
{ showNetDisabledAlertToUser(getActivity());
}
return myView;
FYI
Why you calling
getActivity().getApplicationContext()
You should call getActivity() here .
else showNetDisabledAlertToUser(getActivity().getApplicationContext());
Is the second path in your method. There first one is "if/then" but when that if is not taken; "if/else" kicks. And then ... there is no return statement on that path! And that is what the compiler is telling you.
The real lesson here: if you don't understand such super-basic problems of java, then you should stop doing android work for a while. Instead: work on those java basics. You better focus on learning to crawl before trying to run!

Find internal views of a dynamically created fragment

I have dynamically added a fragment to another fragment.
I need to find a few views within that fragment.
How do I achieve that?
here is my code:
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState)
{
View view = inflater.inflate(R.layout.fragment_educational, container, false);
if (view != null)
{
ButterKnife.inject(this, view);
}
DisposableEducationalFragment disposableEducationalFragment = new DisposableEducationalFragment();
getChildFragmentManager().beginTransaction().add(R.id.fragmentContainer,disposableEducationalFragment).addToBackStack(null).commit();
I want to find these views within that Dynamic fragment:
howItWorks = (RelativeLayout) fragmentView.findViewById(R.id.HowItWorks);
howWeHelp = (RelativeLayout) fragmentView.findViewById(R.id.HowWeHelp);
knowYourBloodPressure = (RelativeLayout) fragmentView.findViewById(R.id.KnowYourBloodPressure);
learnAboutBirthControl = (RelativeLayout) fragmentView.findViewById(R.id.LearnAboutBirthControl);
So, save View view into a temp variable and call it later.
tmpView = view;
and somewhere later:
howItWorks = (RelativeLayout) tempView.findViewById(R.id.HowItWorks);
or , may be, just try it:
howItWorks = (RelativeLayout) getActivity().findViewById(R.id.HowItWorks);

Fragment content does not show up until I switch it and select it again

I've got a problem with my Android app: my fragment content doesn't show up until I switch it and I select it again. What should load just at the fragment start is a list of Cards.
Here you got the onCreate method of the Fragment that loads everything:
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
bundle = this.getArguments();
debts = bundle.getParcelableArrayList("list");
adapter = new CardAdapter(getActivity(), android.R.color.holo_blue_dark);
for (int i=0; i<debts.size();++i) {
Debt d = debts.get(i);
Card card = new Card(d.getSecondUser(),d.getSubject());
adapter.add(card);
}
}
And here the onActivityCreated method where i set the adapter for the list:
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
CardListView list = (CardListView) getView().findViewById(R.id.newCard);
list.setCardTheme(CardTheme.Light);
list.setAdapter(adapter);
}
It works if I use an ArrayList of Cards already loaded, but not this way.
I tried nearly everything... thank you very much.
UPDATE: Even I tried with the solutions you gave me, it keeps happening, my code now:
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
bundle = this.getArguments();
debts = bundle.getParcelableArrayList("list");
adapter = new CardAdapter(getActivity(), android.R.color.holo_blue_dark);
for (int i=0; i<debts.size();++i) {
Debt d = debts.get(i);
Card card = new Card(d.getSecondUser(),d.getSubject());
adapter.add(card);
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_debts, container,
false);
CardListView list = (CardListView) rootView.findViewById(R.id.newCard);
list.setCardTheme(CardTheme.Light);
list.setAdapter(adapter);
return rootView;
}
You should initialize your cardListView inside the onCreateView() method. onCreateView() gets called before the onActivityCreated() method. onCreateView() should be the point when the view of your fragment is initialized.
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
//use your layout file instead of R.layout.fragment_main
View rootView = inflater.inflate(R.layout.fragment_main, container,
false);
CardListView list = rootView.findViewById(R.id.newCard);
list.setCardTheme(CardTheme.Light);
list.setAdapter(adapter);
}
Please take a look at the lifecycle of Fragments.

Android fragment onCreateView() never called

I've been searching for a while now, but I can't seem to find an answer to the following question:
Why does onCreateView never get triggered? This code is the code generated by Android Studio when creating a new MainActivity plus some of the code I wrote.
I want to use setTextConfig(...,...,...) to set the text in the text fields. But I can't seem to get them using findviewbyid(R.id....); because v is always null, even getView(); returns null.
public static class PlaceholderFragment extends Fragment {
private View v;
private EditText etCustomerName, etDeviceID;
private Spinner select;
public PlaceholderFragment() {
super();
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
v = inflater.inflate(R.layout.fragment_main, container, false);
return v;
}
public void setTextConfig(String customerName, String selectedOption, int deviceID){
View vv = getView();
//init form controls
etCustomerName = (EditText)vv.findViewById(R.id.etCustomerName);
etDeviceID = (EditText)v.findViewById(R.id.etDeviceId);
select = (Spinner)v.findViewById(R.id.select);
etCustomerName.setText(customerName);
ArrayAdapter adapter = (ArrayAdapter)select.getAdapter();
int index = adapter.getPosition(selectedOption);
select.setSelection(index);
etDeviceID = (EditText)getView().findViewById(R.id.etDeviceId);
etDeviceID.setText(Integer.toString(deviceID), TextView.BufferType.EDITABLE);
}
}
If you need more detailed info, just ask :)

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