Setting subtitles on a toolbar from a fragment

Question

I am having trouble setting up a subtitle in the toolbar from my snippet. I keep getting the Null Pointer exception in setSubTitle.

@Override public void onActivityCreated(Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState); getActivity().getActionBar().setSubtitle("About"); // NULL POINTER EXCEPTION here } 

Adding a toolbar to a host action:

 @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); toolbar = (Toolbar) findViewById(R.id.toolbar); if (toolbar != null) { Log.w("Rakshak", "Toolbar is not null"); setSupportActionBar(toolbar); } } 

My style.xml

  <style name="AppTheme.Base" parent="Theme.AppCompat.Light.DarkActionBar"> <item name="colorPrimary">#1A7E99</item> <item name="colorPrimaryDark">#16657A</item> <item name="android:windowNoTitle">true</item> <item name="windowActionBar">false</item> </style> 

Here is the Logcat:

 11-12 11:24:15.580: E/AndroidRuntime(22183): FATAL EXCEPTION: main 11-12 11:24:15.580: E/AndroidRuntime(22183): java.lang.NullPointerException 11-12 11:24:15.580: E/AndroidRuntime(22183): at com.driverdesignstudio.drvr.About.onActivityCreated(About.java:63) 11-12 11:24:15.580: E/AndroidRuntime(22183): at android.app.Fragment.performActivityCreated(Fragment.java:1703) 11-12 11:24:15.580: E/AndroidRuntime(22183): at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:903) 11-12 11:24:15.580: E/AndroidRuntime(22183): at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1057) 11-12 11:24:15.580: E/AndroidRuntime(22183): at android.app.BackStackRecord.run(BackStackRecord.java:694) 11-12 11:24:15.580: E/Androidenter code hereRuntime(22183): at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1435) 11-12 11:24:15.580: E/AndroidRuntime(22183): at android.app.FragmentManagerImpl$1.run(FragmentManager.java:441) 11-12 11:24:15.580: E/AndroidRuntime(22183): at android.os.Handler.handleCallback(Handler.java:800) 11-12 11:24:15.580: E/AndroidRuntime(22183): at android.os.Handler.dispatchMessage(Handler.java:100) 11-12 11:24:15.580: E/AndroidRuntime(22183): at android.os.Looper.loop(Looper.java:194) 11-12 11:24:15.580: E/AndroidRuntime(22183): at android.app.ActivityThread.main(ActivityThread.java:5371) 11-12 11:24:15.580: E/AndroidRuntime(22183): at java.lang.reflect.Method.invokeNative(Native Method) 11-12 11:24:15.580: E/AndroidRuntime(22183): at java.lang.reflect.Method.invoke(Method.java:525) 11-12 11:24:15.580: E/AndroidRuntime(22183): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:833) 11-12 11:24:15.580: E/AndroidRuntime(22183): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600) 11-12 11:24:15.580: E/AndroidRuntime(22183): at dalvik.system.NativeStart.main(Native Method) 

Do I need to start interface listeners and listen to the beginning and stop of a fragment in my Fragmentation to set subtitles, or is there an easier way to set subtitles on my toolbar from my fragments.

Let me know if you need to know more about my code.

Greetings.

Answer 1

To use Toolbar and Appcompat 21, you must use AppCompatActivity and use:

 ((AppCompatActivity) getActivity()).getSupportActionBar().setSubtitle("About"); 

Answer 2

instead of calling getActivity (), get a reference to the action from the onAttach () lifecycle method for Fragment.

if you use sherlock actionbar then call getSherlock (). getActionBar ()

Answer 3

You can create one custom layout for this and then use it in the onCreateView method.

 private ActionBar actionBar; 

OnCreateView Method:

 actionBar = getActivity().getActionBar(); if (actionBar != null) { actionBar.setCustomView(R.layout.actionbar_inner_custom_view); actionBar.setDisplayOptions(ActionBar.DISPLAY_SHOW_CUSTOM); } 

Answer 4

Declare the ActionBar toolbar variable and use it as follows:

 toolbar=((AppCompatActivity) getActivity()).getSupportActionBar(); toolbar.setHomeAsUpIndicator(R.drawable.ic_arrow_left); toolbar.setTitle("Detalhes");