how to hide title bar in android studio code example

Example 1: android studio removing title bar

<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar" />

Example 2: hide title bar android

requestWindowFeature(Window.FEATURE_NO_TITLE);
getSupportActionBar().hide();
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,  
               			  WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.activity_main);