Android: how to hide ActionBar on certain activities

If you want to get full screen without actionBar and Title.

Add it in style.xml

<style name="AppTheme.NoActionBar" parent="Theme.AppCompat.Light.DarkActionBar">
      <item name="windowActionBar">false</item>
      <item name="windowNoTitle">true</item>
      <item name="android:windowFullscreen">true</item>
</style>

and use the style at activity of manifest.xml.

<activity ....
      android:theme="@style/AppTheme.NoActionBar" > ......
</activity> 

As you are asking about how to hide in a certain activity, this is what you need :

getSupportActionBar().hide(); 

Apply the following in your Theme for the Activity in AndroidManifest.xml:

<activity android:name=".Activity"
    android:label="@string/app_name"
    android:theme="@android:style/Theme.NoTitleBar">
    <intent-filter>
        <action android:name="android.intent.action.MAIN" />
        <category android:name="android.intent.category.LAUNCHER" />
    </intent-filter>
</activity>

1.Go to your manifest.xml file.

2.Find the activity tag for which you want to hide your ActionBar and then add ,

android:theme="@style/Theme.AppCompat.NoActionBar"

           <activity
            android:name=".MainActivity"
            android:theme="@style/Theme.AppCompat.NoActionBar"
            >