Android Studio eliminando la barra de título
<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar" />
Tough Tarsier
<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar" />
getSupportActionBar().hide();
requestWindowFeature(Window.FEATURE_NO_TITLE);
getSupportActionBar().hide();
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.activity_main);
getSupportActionBar().hide();
change
<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
to
<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">