i want to change the title of the Tabbed Child Activity in android

<android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:layout_weight="1"
        app:layout_scrollFlags="scroll|enterAlways"
        app:popupTheme="@style/AppTheme.PopupOverlay"
        app:title="@string/app_name">

    </android.support.v7.widget.Toolbar>

The above is the code which is in the actitvity_main2.xml which is the child activity of activity_main.xml.

I want to change the title of this child activity when I pass from Main activity to Main2Acitivty. This is the picture which has the title of the main application(i.e. Stocks).

I want to change the title to something else when Main2Activity(this activity contains Tabbed views as you can see in the image) is loaded. I tried to use getActionBar().setTitle(<name to put on title>); and also used setTitle(<name to put in the title>) but nothing worked.

Please help as I am new to android.

Make Style in sytle.xml file

<style name="AppTheme.NoActionBar">
    <item name="windowActionBar">false</item>
    <item name="windowNoTitle">true</item>
</style>

Call below code from your first activity

Intent intent = new Intent(FirstActivity.this, MainActivity.class);
intent.putExtra("TitleBarName","FirstActivity");
startActivity(intent);

On SecondActivity

    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);
    String titleName = getIntent().getStringExtra("TitleBarName");
    getSupportActionBar().setTitle(titleName);

and make sure to check in manifest file.

if you use toolbar then you have to put this theme in that activity in manifest file

    <activity
        android:name=".MainActivity"
        android:label="@string/app_name"
        android:theme="@style/AppTheme.NoActionBar">
    </activity>

I hope this will resolve your issue.