How can I get the context in a fragment?
I need to use my database whose constructor takes in the context, but getApplicationContext() and FragmentClass.this don't work so what can I do?
Database constructor
public Database(Context ctx)
{
this.context = ctx;
DBHelper = new DatabaseHelper(context);
}
You can use getActivity(), which returns the activity associated with a fragment.
The activity is a context (since Activity extends Context).
The easiest and most precise way to get the context of the fragment that I found is to get it directly from the ViewGroup when you call onCreateView method at least here you are sure not to get null for getActivity():
public class Animal extends Fragment {
Context thiscontext;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
thiscontext = container.getContext();
Always use the getActivity() method to get the context of your attached activity, but always remember one thing: Fragments are slightly unstable and getActivity returns null some times, so for that, always check the isAdded() method of fragment before getting context by getActivity().
Previously I'm using onAttach (Activity activity) to get context in Fragment
Problem
The onAttach (Activity activity) method was deprecated in API level 23.
Solution
Now to get context in Fragment we can use onAttach (Context context)
onAttach (Context context)
context. onCreate(Bundle) will be called after this. Documentation
/**
* Called when a fragment is first attached to its context.
* {@link #onCreate(Bundle)} will be called after this.
*/
@CallSuper
public void onAttach(Context context) {
mCalled = true;
final Activity hostActivity = mHost == null ? null : mHost.getActivity();
if (hostActivity != null) {
mCalled = false;
onAttach(hostActivity);
}
}
SAMPLE CODE
public class FirstFragment extends Fragment {
private Context mContext;
public FirstFragment() {
// Required empty public constructor
}
@Override
public void onAttach(Context context) {
super.onAttach(context);
mContext=context;
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rooView=inflater.inflate(R.layout.fragment_first, container, false);
Toast.makeText(mContext, "THIS IS SAMPLE TOAST", Toast.LENGTH_SHORT).show();
// Inflate the layout for this fragment
return rooView;
}
}
We can also use getActivity() to get context in Fragments
but getActivity() can return null if the your fragment is not currently attached to a parent activity,
You could also get the context from the inflater parameter, when overriding onCreateView.
public static class MyFragment extends Fragment {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
/* ... */
Context context = inflater.getContext();
/* ... */
}
}
to get the context inside the Fragment will be possible using getActivity() :
public Database()
{
this.context = getActivity();
DBHelper = new DatabaseHelper(this.context);
}
Activity associated with the fragment using getActivity(), you can use it but is not recommended it will cause memory leaks.I think a better aproach must be getting the Activity from the onAttach() method:
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
context = activity;
}
Ideally, you should not need to use globals. The fragment has different notifications, one of them being onActivityCreated. You can get the instance of the activity in this lifecycle event of the fragment.
Then: you can dereference the fragment to get activity, context or applicationcontext as you desire:
this.getActivity() will give you the handle to the activity
this.getContext() will give you a handle to the context
this.getActivity().getApplicationContext() will give you the handle to the application context. You should preferably use the application context when passing it on to the db.
The simple way is to use getActivity(). But I think the major confusion of using the getActivity() method to get the context here is a null pointer exception.
For this, first check with the isAdded() method which will determine whether it's added or not, and then we can use the getActivity() to get the context of Activity.
public class MenuFragment extends Fragment implements View.OnClickListener {
private Context mContext;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
FragmentMenuBinding binding=FragmentMenuBinding.inflate(inflater,container,false);
View view=binding.getRoot();
mContext=view.getContext();
return view;
}
}
I need context for using arrayAdapter IN fragment, when I was using getActivity error occurs but when i replace it with getContext it works for me
listView LV=getView().findViewById(R.id.listOFsensors);
LV.setAdapter(new ArrayAdapter<String>(getContext(),android.R.layout.simple_list_item_1 ,listSensorType));
Inside fragment for kotlin sample would help someone
textViewStatus.setTextColor(ContextCompat.getColor(context!!, R.color.red))
if you use databinding;
bindingView.textViewStatus.setTextColor(ContextCompat.getColor(context!!, R.color.red))
Where bindingView is initialized in onCreateView like this
private lateinit var bindingView: FragmentBookingHistoryDetailBinding
bindingView = DataBindingUtil.inflate(inflater, R.layout.your_layout_xml, container, false)
