<application
    android:theme="@style/Theme.AppCompat.Light.NoActionBar">

//繼承自Activity時使用
requestWindowFeature(Window.FEATURE_NO_TITLE);
 
//繼承自AppCompatActivity時使用
getSupportActionBar().hide();

android:theme="@android:style/Theme.NoTitleBar.Fullscreen" 
或者 
android:theme="@android:style/Theme.Black.NoTitleBar.Fullscreen"

requestWindowFeature(Window.FEATURE_NO_TITLE);
 
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.FLAG_FULLSCREEN);

android:screenOrientation=""

setRequestedOrientation(@ActivityInfo.ScreenOrientationint requestedOrientation);

/**
* The preferred screen orientation this activity would like to run in.
* From the {@link android.R.attr#screenOrientation} attribute, one of
* {@link #SCREEN_ORIENTATION_UNSPECIFIED},
* {@link #SCREEN_ORIENTATION_LANDSCAPE},
* {@link #SCREEN_ORIENTATION_PORTRAIT},
* {@link #SCREEN_ORIENTATION_USER},
* {@link #SCREEN_ORIENTATION_BEHIND},
* {@link #SCREEN_ORIENTATION_SENSOR},
* {@link #SCREEN_ORIENTATION_NOSENSOR},
* {@link #SCREEN_ORIENTATION_SENSOR_LANDSCAPE},
* {@link #SCREEN_ORIENTATION_SENSOR_PORTRAIT},
* {@link #SCREEN_ORIENTATION_REVERSE_LANDSCAPE},
* {@link #SCREEN_ORIENTATION_REVERSE_PORTRAIT},
* {@link #SCREEN_ORIENTATION_FULL_SENSOR},
* {@link #SCREEN_ORIENTATION_USER_LANDSCAPE},
* {@link #SCREEN_ORIENTATION_USER_PORTRAIT},
* {@link #SCREEN_ORIENTATION_FULL_USER},
* {@link #SCREEN_ORIENTATION_LOCKED},
*/

android:configChanges="orientation|keyboardHidden|screenSize"

@Override 
public void onConfigurationChanged(Configuration newConfig) { 
  	super.onConfigurationChanged(newConfig); 
  	if (this.getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE) {
    		// land do nothing is ok
    		Toast.makeText(MainActivity.this,"現在是橫屏", Toast.LENGTH_SHORT).show();
  	} else if (this.getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT) {
    		// port do nothing is ok
    		Toast.makeText(MainActivity.this,"現在是豎屏",Toast.LENGTH_SHORT).show();;
  	}
}