Setting Custom ActionBar Title from Fragment
Solution 1:
What you're doing is correct. Fragments
don't have access to the ActionBar
APIs, so you have to call getActivity
. Unless your Fragment
is a static inner class, in which case you should create a WeakReference
to the parent and call Activity.getActionBar
from there.
To set the title for your ActionBar
, while using a custom layout, in your Fragment
you'll need to call getActivity().setTitle(YOUR_TITLE)
.
The reason you call setTitle
is because you're calling getTitle
as the title of your ActionBar
. getTitle
returns the title for that Activity
.
If you don't want to get call getTitle
, then you'll need to create a public method that sets the text of your TextView
in the Activity
that hosts the Fragment
.
In your Activity:
public void setActionBarTitle(String title){
YOUR_CUSTOM_ACTION_BAR_TITLE.setText(title);
}
In your Fragment:
((MainFragmentActivity) getActivity()).setActionBarTitle(YOUR_TITLE);
Docs:
Activity.getTitle
Activity.setTitle
Also, you don't need to call this.whatever
in the code you provided, just a tip.
Solution 2:
===Update October, 30, 2019===
Since we have new components such as ViewModel and LiveData, we can have a different/easier way to update Activity Title from Fragment by using ViewModel and Live Data
Activity
class MainActivity : AppCompatActivity() {
private lateinit var viewModel: MainViewModel
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.main_activity)
if (savedInstanceState == null) {
supportFragmentManager.beginTransaction()
.replace(R.id.container, MainFragment.newInstance())
.commitNow()
}
viewModel = ViewModelProviders.of(this).get(MainViewModel::class.java)
viewModel.title.observe(this, Observer {
supportActionBar?.title = it
})
} }
MainFragment
class MainFragment : Fragment() {
companion object {
fun newInstance() = MainFragment()
}
private lateinit var viewModel: MainViewModel
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?): View {
return inflater.inflate(R.layout.main_fragment, container, false)
}
override fun onActivityCreated(savedInstanceState: Bundle?) {
super.onActivityCreated(savedInstanceState)
activity?.run {
viewModel = ViewModelProviders.of(this).get(MainViewModel::class.java)
} ?: throw Throwable("invalid activity")
viewModel.updateActionBarTitle("Custom Title From Fragment")
} }
And MainModelView:
class MainViewModel : ViewModel() {
private val _title = MutableLiveData<String>()
val title: LiveData<String>
get() = _title
fun updateActionBarTitle(title: String) = _title.postValue(title) }
And then you can update the Activity title from Fragment using viewModel.updateActionBarTitle("Custom Title From Fragment")
===Update April, 10, 2015===
You should use listener to update your action bar title
Fragment:
public class UpdateActionBarTitleFragment extends Fragment {
private OnFragmentInteractionListener mListener;
public UpdateActionBarTitleFragment() {
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
if (mListener != null) {
mListener.onFragmentInteraction("Custom Title");
}
return inflater.inflate(R.layout.fragment_update_action_bar_title2, container, false);
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
mListener = (OnFragmentInteractionListener) activity;
} catch (ClassCastException e) {
throw new ClassCastException(activity.toString()
+ " must implement OnFragmentInteractionListener");
}
}
@Override
public void onDetach() {
super.onDetach();
mListener = null;
}
public interface OnFragmentInteractionListener {
public void onFragmentInteraction(String title);
}
}
And Activity:
public class UpdateActionBarTitleActivity extends ActionBarActivity implements UpdateActionBarTitleFragment.OnFragmentInteractionListener {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_update_action_bar_title);
}
@Override
public void onFragmentInteraction(String title) {
getSupportActionBar().setTitle(title);
}
}
Read more here: https://developer.android.com/training/basics/fragments/communicating.html
Solution 3:
Google examples tend to use this within the fragments.
private ActionBar getActionBar() {
return ((ActionBarActivity) getActivity()).getSupportActionBar();
}
The fragment will belong to an ActionBarActivity and that is where the reference to the actionbar is. This is cleaner because the fragment doesn't need to know exactly what activity it is, it only needs to belong to an activity that implements ActionBarActivity. This makes the fragment more flexible and can be added to multiple activities like they are meant to.
Now, all you need to do in the fragment is.
getActionBar().setTitle("Your Title");
This works well if you have a base fragment that your fragments inherit from instead of the normal fragment class.
public abstract class BaseFragment extends Fragment {
public ActionBar getActionBar() {
return ((ActionBarActivity) getActivity()).getSupportActionBar();
}
}
Then in your fragment.
public class YourFragment extends BaseFragment {
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
getActionBar().setTitle("Your Title");
}
}
Solution 4:
Setting Activity
’s title from a Fragment
messes up responsibility levels. Fragment
is contained within an Activity
, so this is the Activity
, which should set its own title according to the type of the Fragment
for example.
Suppose you have an interface:
interface TopLevelFragment
{
String getTitle();
}
The Fragment
s which can influence the Activity
’s title then implement this interface. While in the hosting activity you write:
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
FragmentManager fm = getFragmentManager();
fm.beginTransaction().add(0, new LoginFragment(), "login").commit();
}
@Override
public void onAttachFragment(Fragment fragment)
{
super.onAttachFragment(fragment);
if (fragment instanceof TopLevelFragment)
setTitle(((TopLevelFragment) fragment).getTitle());
}
In this manner Activity
is always in control what title to use, even if several TopLevelFragment
s are combined, which is quite possible on a tablet.
Solution 5:
I don't think that the accepted answer is a perfect answer for it. Since all the activities that use
Toolbar
are extended using
AppCompatActivity
, the fragments called from it can use the below mentioned code for changing the title.
((AppCompatActivity) context).getSupportActionBar().setTitle("Your Title");