查看方向更改时未找到片段

Question

我正在为c＃xamarin编写应用程序。此代码具有普遍性，应该几乎适用于Android。所以这个问题对于Java和C＃都是有效的。

所以我得到了这个应用程序，我的MainActivity是我的片段管理器。它正在替换像这样的片段：

private void SelectItem(int position) 
    { 

     currentFragment = null; 
     Fragment findFrag = null; 

     string tag = ""; 
     var arguments = new Bundle(); 
     switch(position) { 
     case 0: // <-- Home Menu item 

       tag = "home"; 

       findFrag = FragmentManager.FindFragmentByTag (tag); 

       if (findFrag != null) { 
        currentFragment = findFrag; 
       } else { 
        currentFragment = new HomeFragment(); 
       } 


      break; 
      case 1: // <-- Picture Menu item 

       tag = "picture"; 

      findFrag = FragmentManager.FindFragmentByTag (tag); 

       if (findFrag != null) { 
        currentFragment = findFrag; 
       } else { 
        currentFragment = new PictureFragment(); 
       } 

      break; 
      case 2: // <-- Album Menu item 

       tag = "album"; 

      findFrag = FragmentManager.FindFragmentByTag (tag); 

       if (findFrag != null) { 
        currentFragment = findFrag; 
       } else { 
        currentFragment = new AlbumFragment(); 
       } 

      break; 
      case 3: // <-- Settings Menu item 

       tag = "settings"; 

      findFrag = FragmentManager.FindFragmentByTag (tag); 

       if (findFrag != null) { 
        currentFragment = findFrag; 
       } else { 
        currentFragment = new SettingsFragment(); 
       } 

      break; 
      case 4: // <-- Logout Menu item 
       System.Diagnostics.Debug.WriteLine ("You should be logging out"); 
      break; 
     } 

     FragmentManager.BeginTransaction() 
      .Replace(Resource.Id.content_frame, currentFragment, tag) 
      .AddToBackStack(null)    
       .Commit(); 



     _drawerList.SetItemChecked(position, true); 
     ActionBar.Title = _title = _menuTitles[position]; 

     // Always close drawer when an item has been selected. 
     _drawer.CloseDrawer (_drawerList); 

    } 

这一切都开始良好，我可以在片段之间切换。但是，当我改变方向，它与以下错误消息崩溃：

No view found for id 0x7f080014 (PhotoWapp.PhotoWapp:id/content_frame) for fragment PictureFragment{b52cb3b0 #1 id=0x7f080014 picture} 
[FragmentManager] Activity state: 
[FragmentManager] Local Activity b52f3060 State: 
[FragmentManager]  mResumed=false mStopped=false mFinished=false 
[FragmentManager]  mLoadersStarted=false 
[FragmentManager]  mChangingConfigurations=false 
[FragmentManager]  mCurrentConfig={1.0 310mcc260mnc en_US ldltr sw320dp w533dp h294dp 240dpi nrml long land finger qwerty/v/v tball/v s.7} 
[FragmentManager] Active Fragments in b52f3150: 

在我的片段我设置RetainInstance = true和，但由于某种原因，无法找到参考Resource.Id.content_frame ..我应该做些什么来防止这发生了什么？

其中引用Resource.Id.content_frame的布局为：Resource.Layout.Main。而像这样：

<?xml version="1.0" encoding="utf-8"?> 
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:id="@+id/drawer_layout" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent"> 
<!-- The main content view --> 
    <FrameLayout 
     android:id="@+id/content_frame" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" /> 
<!-- The navigation drawer --> 
    <ListView 
     android:id="@+id/left_drawer" 
     android:layout_width="240dp" 
     android:layout_height="match_parent" 
     android:layout_gravity="start" 
     android:choiceMode="singleChoice" 
     android:divider="@android:color/transparent" 
     android:dividerHeight="0dp" 
     android:background="#111" /> 
</android.support.v4.widget.DrawerLayout> 

Answer 1

我认为你应该使用的，而不是Resource.Id Resource.Layout.nameofxmlresource ...