Android中Activity被系统会收前页面信息保存

1、重写onSaveInstanceState方法

protected void onSaveInstanceState(Bundle outState) {

    super.onSaveInstanceState(outState);

}

2、在onCreate方法中判断（Bundle savedInstanceState）对象是否为空

public void onCreate(Bundle savedInstanceState) {

//判断 savedInstanceState是不是空.

//如果不为空就取出来

        super.onCreate(savedInstanceState);

}