Disable Landscape Mode

disable landscape mode for all or one activity:

in manifest
<android . . . >
    . . .
    <manifest . . . >
        . . .
        <application>
            <activity android:name=".MyActivity"
                android:screenOrientation="portrait"
                android:configChanges="keyboardHidden|orientation">
            </activity>
        </application>
    </manifest>
</android>

in activity oncreate

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
}