private String data="some user data";

@Override
protected void onCreate(Bundle savedInstanceState) {
	super.onCreate(savedInstanceState);
	if(savedInstanceState!=null) {//如果有数据被需恢复，onRestoreInstanceState会被触发，并将savedInstanceState传递到onCreate
		Log.d(TAG,"onRestoreInstanceState is not null...");
		data=savedInstanceState.getString("data");
	}
	
	//tv.setText(data);
}

@Override
protected void onSaveInstanceState(Bundle outState) {
	super.onSaveInstanceState(outState);
	outdate.putString("data", data);
}

@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {//savedInstanceState会传递到onCreate，在onCreate中恢复
	super.onRestoreInstanceState(savedInstanceState);
	//data=savedInstanceState.getString("data");//不在这里用data=savedInstanceState.getString("data");直接来恢复。
}