java在屏幕旋转时不保存当前片段和数据

Question

我是初学者，我不懂，请帮忙。我有NavigationView和几个页面片段。问题是：如果我将方向更改为横向，然后重置移动到主屏幕的数据。你如何解决这个问题

代码main活动。Oncreate（）

protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
    setContentView(R.layout.layout_main);
   //removed unnecessary codes
    navigationView.setNavigationItemSelectedListener(this);
    transaction.beginTransaction().replace(R.id.container, fragment_main).commit();
}

以及navigationview的void onNavigationItemSelected（）

switch (item.getItemId())
 {
     case R.id.nav_main :
  transaction.beginTransaction().replace(R.id.container,fragment_main).commit();
         break;
     case R.id.nav_report_category:
         transaction.beginTransaction().replace(R.id.container,fragment_category).commit();
         break;

     case R.id.nav_history:
         transaction.beginTransaction().replace(R.id.container,fragment_history).commit();
         break;
 }

    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    drawer.closeDrawer(GravityCompat.START);
    return true;