You can do it programatically:
public class ActivityName extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// remove title
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.main);
}
}
Or you can do it via your AndroidManifest.xml file:
<activity android:name=".ActivityName"
android:label="@string/app_name"
android:theme="@android:style/Theme.NoTitleBar.Fullscreen"/>
Edit:
If you are using AppCompatActivity then you need to add new theme
<style name="Theme.AppCompat.Light.NoActionBar.FullScreen" parent="@style/Theme.AppCompat.Light.NoActionBar">
<item name="android:windowNoTitle">true</item>
<item name="android:windowActionBar">false</item>
<item name="android:windowFullscreen">true</item>
<item name="android:windowContentOverlay">@null</item>
</style>
and then use it.
<activity android:name=".ActivityName"
android:label="@string/app_name"
android:theme="@style/Theme.AppCompat.Light.NoActionBar.FullScreen"/>