How to Set selected item in BottomNavigationView

Question

I am trying to set default item on activity created but it isn't working? This is my code:

protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(R.layout.activity_userhome);     mTextMessage = (TextView) findViewById(R.id.message);     profile = (FrameLayout) findViewById(R.id.profile);     mall = (FrameLayout) findViewById(R.id.mall);     dietplan =(FrameLayout) findViewById(R.id.dietplan);     BottomNavigationView navigation = (BottomNavigationView)      findViewById(R.id.navigation);     navigation.setSelectedItemId(R.id.dietplan);      navigation.setOnNavigationItemSelectedListener      (mOnNavigationItemSelectedListener); } 

But it seems that navigation.setSelectedItemId(R.id.dietplan); is not working. Please help me to set default item of bottom navigation bar:

This is my stack trace(logcat):

FATAL EXCEPTION: main    Process: gym.android.ommsoftware.gym, PID: 1915    java.lang.RuntimeException: Unable to start activity ComponentInfo{gym.android.ommsoftware.gym/gym.android.ommsoftware.gym.Userhome}: java.lang.NullPointerException        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2404)        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2464)        at android.app.ActivityThread.access$900(ActivityThread.java:172)        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1308)        at android.os.Handler.dispatchMessage(Handler.java:102)        at android.os.Looper.loop(Looper.java:146)        at android.app.ActivityThread.main(ActivityThread.java:5653)        at java.lang.reflect.Method.invokeNative(Native Method)        at java.lang.reflect.Method.invoke(Method.java:515)        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1291)        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1107)        at dalvik.system.NativeStart.main(Native Method)     Caused by: java.lang.NullPointerException        at gym.android.ommsoftware.gym.Userhome.onCreate(Userhome.java:57)        at android.app.Activity.performCreate(Activity.java:5541)        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1093)        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2368)        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2464)         at android.app.ActivityThread.access$900(ActivityThread.java:172)         at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1308)         at android.os.Handler.dispatchMessage(Handler.java:102)         at android.os.Looper.loop(Looper.java:146)         at android.app.ActivityThread.main(ActivityThread.java:5653)         at java.lang.reflect.Method.invokeNative(Native Method)         at java.lang.reflect.Method.invoke(Method.java:515)         at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1291)         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1107)         at dalvik.system.NativeStart.main(Native Method)  

Answer 1

Instead of selected you need to setChecked(true) that item. Try this code

mBottomNavigationView=(BottomNavigationView)findViewById(R.id.bottom_nav); mBottomNavigationView.getMenu().findItem(R.id.item_id).setChecked(true); 

Checked item is highlighted in BottomNavigationView.