片段Xamarin的Android

Question

海兰大家，

我试图取代片段，但它不工作...我有一个活动，这个活动里面我有两个按钮和一个的LinearLayout，我想取代许多片段在LinearLayout中使用按钮Next和Previuos，第一个片段工作，但第二个不起作用。

有人可以解释我该怎么做？

活动

ing System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 

using Android.App; 
using Android.Content; 
using Android.OS; 
using Android.Runtime; 
using Android.Views; 
using Android.Widget; 
using Android.Support.V7.App; 
using Uer.Fragments.FragmentsRegister; 

namespace Uer 
{ 
    [Activity(Label = "Register", Theme = "@style/NoActionBar")] 

    public class RegisterActivity : AppCompatActivity 
    { 

     private LinearLayout lnlContainerRegister; 
     private Button btnNext; 

     protected override void OnCreate(Bundle savedInstanceState) 
     { 
      base.OnCreate(savedInstanceState); 

      // Create your application here 
      SetContentView(Resource.Layout.RegisterActivity); 

      lnlContainerRegister = FindViewById<LinearLayout>(Resource.Id.lnlContainerRegister); 
      btnNext = FindViewById<Button>(Resource.Id.btnNext); 

      cpfFragment(); 

      btnNext.Click += BtnNext_Click; 
     } 

     private void BtnNext_Click(object sender, EventArgs e) 
     { 
      emailFragment(); 
     } 

     void cpfFragment() 
     { 

      var transaction = SupportFragmentManager.BeginTransaction(); 
      transaction.Add(Resource.Id.lnlContainerRegister, new CPF(), "CPF"); 
      transaction.Commit(); 

     } 

     void emailFragment() 
     { 
      var transaction = SupportFragmentManager.BeginTransaction(); 
      transaction.Add(Resource.Id.lnlContainerRegister, new Email(), "Email"); 
      transaction.Commit(); 
     } 
    } 
} 

CPF片段

sing System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 

using Android.Content; 
using Android.OS; 
using Android.Runtime; 
using Android.Util; 
using Android.Views; 
using Android.Widget; 
using Android.Support.V4.App; 

namespace Uer.Fragments.FragmentsRegister 
{ 
    public class CPF : Fragment 
    { 
     public override void OnCreate(Bundle savedInstanceState) 
     { 
      base.OnCreate(savedInstanceState); 

      // Create your fragment here 
     } 

     public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) 
     { 
      // Use this to return your custom view for this Fragment 
      View view = inflater.Inflate(Resource.Layout.CPFFragment, container, false); 

      return view; 
     } 
    } 
} 

电子邮件片段

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 

using Android.Content; 
using Android.OS; 
using Android.Runtime; 
using Android.Util; 
using Android.Views; 
using Android.Widget; 
using Android.Support.V4.App; 

namespace Uer.Fragments.FragmentsRegister 
{ 
    public class Email : Fragment 
    { 
     public override void OnCreate(Bundle savedInstanceState) 
     { 
      base.OnCreate(savedInstanceState); 

      // Create your fragment here 
     } 

     public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) 
     { 
      // Use this to return your custom view for this Fragment 
      View view = inflater.Inflate(Resource.Layout.EmailFragment, container, false); 

      return view; 
     } 
    } 
} 

PS：该作品cpfFragment normaly！

Answer 1

尝试将FrameLayout添加到您的Activity的XML。

<FrameLayout 
     android:id="@+id/myFrameLayout" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" /> 

然后，使用supportFragmentManager的方法Replace（）而不是方法Add（）。

你会得到这样的事情：

void cpfFragment() 
     { 

      var transaction = SupportFragmentManager.BeginTransaction(); 
      transaction.Replace(Resource.Id.myFrameLayout, new CPF(), "CPF"); 
      transaction.Commit(); //or CommitAllowingStateLoss 

     } 

有了这个代码，您的活动的FrameLayout将包含片段CPF的视图。

然后，您将不得不为您的电子邮件片段调用相同的代码，并且将清理FrameLayout，并将电子邮件片段的视图添加到其中。

void emailFragment() 
    { 
     var transaction = SupportFragmentManager.BeginTransaction(); 
     transaction.Replace(Resource.Id.myFrameLayout, new Email(), "Email"); 
     transaction.Commit(); //or CommitAllowingStateLoss 
    } 

告诉我，如果它的工作原理:)

编辑：回答这个问题的评论：

你必须创建一个接口，你的活动应该实现它：

public interface IChangeFragment 
{ 
    void emailFragment(); 
    void cpfFragment(); 
} 

public class RegisterActivity : AppCompatActivity, IChangeFragment 
{ 
    //... 

    public void emailFragment() 
    { 
     //... 
    } 

    public void cpfFragment() 
    { 
     //... 
    } 
} 

然后，你的片段必须使用IChangeFragment类型的回调函数。回调将在片段的OnAttach方法进行估值，你将能够调用您的活动的方法，从您的片段：

public class CPF : Fragment 
{ 
     private IChangeFragment m_callBack; 

     public override void OnAttach(Activity activity) 
     { 
      base.OnAttach(activity); 

      try 
      { 
       m_callBack = (IChangeFragment)activity; 
      } 
      catch (ClassCastException) 
      { 
       throw new ClassCastException(activity.ToString() + " must implement IChangeFragment"); 
      } 
     } 

     private void OnButtonClicked(object sender, EventArgs e) 
     { 
      m_callBack.emailFragment(); 
     } 
} 

注意，用这种方法，使用这些片段的任何活动将必须实现接口IChangeFragment。如果没有，你将得到一个ClassCastException。