フラグメントで回転すると、エラーになる。

05-09 17:52:30.111: E/AndroidRuntime(18572): Caused by: java.lang.IllegalArgumentException: Binary XML file line #8: Duplicate id 0x7f07001c, tag null, or parent id 0x7f07001b with another fragment for myapp.app.FragView

　　　　修正前
	@Override
	public void onCreate(final Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		FragMain fragMain = new FragMain();
		FragmentManager manager = getFragmentManager();
		FragmentTransaction transaction = manager.beginTransaction();
		
		transaction.add(android.R.id.content, fragMain);
		transaction.commit();
	}

　　　　修正後
	@Override
	public void onCreate(final Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		FragMain fragMain = new FragMain();
		FragmentManager manager = getFragmentManager();
		
		if (manager.findFragmentById(android.R.id.content) == null) {
			FragmentTransaction transaction = manager.beginTransaction();
			transaction.add(android.R.id.content, fragMain);
			transaction.commit();
		}
	}

java - Android fragment is not working - Stack Overflow