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Fragmentの中にはViewPagerがホストされています。テストとして、私は次のように同じクラスの3つの断片を使用して初期化：私のFragmentオブジェクトを動的にViewPagerに追加されますのでViewPager子フラグメント空き
mAdapter = new GenericFragmentPagerAdapter(ChildFragmentManager);
mAdapter.Add(frag1);
mAdapter.Add(frag2);
mAdapter.Add(frag3);
mViewPager = Activity.FindViewById<ViewPager>(Resource.Id.fragment_navigation_viewpager);
mViewPager.Adapter = mAdapter;
mTabLayout = Activity.FindViewById<TabLayout>(Resource.Id.tab_layout);
mTabLayout.SetupWithViewPager(mViewPager);
、私GenericFragmentPagerAdapterはFragmentStatePagerAdapterを拡張します。 ViewPagerをホスティング
Fragmentは、次のようにNavigationViewをホストしている私のActivity内でインスタンス化されます。
NavigationFragment fragment = NavigationFragment.NewInstance();
SupportFragmentManager.BeginTransaction().
Replace(Resource.Id.activity_main_content_container,fragment).
Commit();
私の問題がある：3つの断片がViewPagerに正しく追加されますが、とfrag3はfrag2に対し、空の見えます内容を正しく示しています。デバッガを実行すると、とfrag3が正しくインスタンス化されるため、なぜそれらが空に見えるのかわかりません。
明らかに、ネストされたフラグメントを使用する場合、アダプタはgetChildFragmentManager()を使用して初期化する必要があります。残念ながら、私はまだgetSupportFragmentManager()を使用した場合と同じ効果を得ます。
何か不足していますか、または問題をデバッグする方法はありますか？
編集
私が発生している問題のより良いアイデアを得ることができました。何らかの理由で、もし私の断片がListFragmentに広がっていると、ViewPagerは正しくロードされ、その子を表示します。しかし、通常のFragmentを使用すると、問題が発生します。正直なところ、私は理由が分からないので、誰かがそれを試してみたい場合に備えて、以下のコードを用意しました。
MainAcitivty.cs
namespace App
{
[Activity(Label = "TestActivity", Theme = "@style/FM360MaterialTheme",
ConfigurationChanges = Android.Content.PM.ConfigChanges.Orientation | Android.Content.PM.ConfigChanges.ScreenSize)]
public class TestActivity : FragmentActivity
{
TabLayout mTabLayout;
ViewPager mViewPager;
GenericFragmentPagerAdapter mAdapter;
static FMNavigation mFMNavigation;
protected override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
// Create your application here
// Set our view from the "startup" layout resource
SetContentView(Resource.Layout.fragment_navigation);
InitializeNavigation();
}
private void InitializeNavigation()
{
ProgressDialog progressDialog = ProgressDialog.Show(
this,
GetString(Resource.String.Initializing),
GetString(Resource.String.one_moment)
);
new Thread(new ThreadStart(delegate {
// Here the mFMNavigation variable is initialized
// because it required downloaded data from the internet.
RunOnUiThread(() =>
{
progressDialog.Dismiss();
// If no error occured, initialize UI components.
InitializeUserInterface();
});
})).Start();
}
private void InitializeUserInterface()
{
string fragmentTitle = "Test Fragment Title";
// Items that will be inserted inside the adapter.
var datasource = mFMNavigation.CurrentItem.Datasource;
NavigationListFragment f1 = NavigationListFragment.NewInstance(
datasource,
mFMNavigation,
"Title 1");
NavigationListFragment f2 = NavigationListFragment.NewInstance(
datasource,
mFMNavigation,
"Title 2");
mAdapter = new GenericFragmentPagerAdapter(SupportFragmentManager);
mAdapter.Add(f1);
mAdapter.Add(f2);
mViewPager = FindViewById<ViewPager>(Resource.Id.fragment_navigation_viewpager);
mViewPager.Adapter = mAdapter;
mTabLayout = FindViewById<TabLayout>(Resource.Id.tab_layout);
mTabLayout.SetupWithViewPager(mViewPager);
}
}
}
GenericFragmentPagerAdapter.cs
using Android.Support.V4.App;
using System.Collections.Generic;
namespace Adapters
{
public class GenericFragmentPagerAdapter : FragmentStatePagerAdapter
{
private List<Fragment> mFragments;
public GenericFragmentPagerAdapter (FragmentManager fm) : base(fm)
{
mFragments = new List<Fragment>();
}
public void Add(Fragment fragment)
{
if (!mFragments.Contains (fragment))
mFragments.Add (fragment);
}
public void Remove(Fragment fragment)
{
if (mFragments.Contains (fragment))
mFragments.Remove (fragment);
}
public void RemoveAt(int position)
{
if (mFragments.Count <= position)
return;
mFragments.RemoveAt(position);
}
public void RemoveUntil(int position)
{
position++;
while (mFragments.Count > position)
mFragments.RemoveAt(position);
}
public override int Count { get { return mFragments.Count; }}
public override Fragment GetItem(int position) { return mFragments [position]; }
public override int GetItemPosition(Java.Lang.Object item) { return PositionNone; }
public override Java.Lang.ICharSequence GetPageTitleFormatted(int position)
{
Fragment f = mFragments[position];
if (f is NavigationListFragment)
{
NavigationListFragment listFragment = (NavigationListFragment)f;
return new Java.Lang.String(listFragment.FragmentTitle);
}
return new Java.Lang.String("");
}
}
}
NavigationListFragment.cs
namespace App.Fragments
{
public class NavigationListFragment : Fragment
{
List<FMNavigationListItem> mDatasource;
FMNavigation mFMNavigation;
string mFragmentTitle;
ExpandableListviewAdapter mAdapter;
public NavigationListFragment()
{
}
public static NavigationListFragment NewInstance(List<FMNavigationListItem> items, FMNavigation navigation, string fragmentTitle)
{
NavigationListFragment f = new NavigationListFragment();
f.mFMNavigation = navigation;
f.mDatasource = items;
f.mFragmentTitle = fragmentTitle;
return f;
}
public override void OnActivityCreated(Bundle savedInstanceState)
{
base.OnActivityCreated(savedInstanceState);
RetainInstance = true;
InitializeListView();
}
public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
return inflater.Inflate(
Resource.Layout.fragment_navigation_list,
container,
false);
}
/// <summary>
///
/// </summary>
void InitializeListView()
{
ExpandableListView listView = Activity.FindViewById<ExpandableListView>(
Resource.Id.fragment_navigation_list_expandable_listview);
// "Remove" listview and set empty state.
if (mDatasource == null || mDatasource.Count <= 0)
{
TextView emptyView = Activity.FindViewById<TextView>(
Resource.Id.fragment_navigation_list_empty_textview);
emptyView.Text = GetString(Resource.String.empty_list_text);
listView.Visibility = ViewStates.Gone;
return;
}
// Here we build a list of groupable items based on the
// data source given.
List<ExpandableItem> groupItems = new List<ExpandableItem>();
foreach (var dataItem in mDatasource)
{
string className = mFMNavigation.NameOfClassId(dataItem.ClassId);
// Attempt to find the group that has the same class name.
// If it exists add the data item to the group. Otherwise
// create a new group and add the item.
ExpandableItem groupItem = groupItems.Find(x => x.GroupTitle.Equals(className));
if (groupItem == null)
{
ExpandableItem item = new ExpandableItem();
item.GroupTitle = className;
item.ChildItems = new List<FMNavigationListItem>();
item.ChildItems.Add(dataItem);
groupItems.Add(item);
continue;
}
groupItem.ChildItems.Add(dataItem);
}
mAdapter = new ExpandableListviewAdapter(Activity, groupItems);
listView.SetAdapter(mAdapter);
}
#region Fragment Properties
public string FragmentTitle
{
get { return mFragmentTitle; }
}
#endregion
}
}
ExpandableListviewAdapter.cs
namespace App.Adapters
{
class ExpandableListviewAdapter : BaseExpandableListAdapter
{
private Activity mContext;
private List<ExpandableItem> mDataItems;
public ExpandableListviewAdapter(Activity context, List<ExpandableItem> items)
: base()
{
mContext = context;
mDataItems = items;
// Sort the groups and all of its child elements alphabetically.
SortDataItems();
}
void SortDataItems()
{
// Sort each group alphabetically.
mDataItems.Sort(delegate (ExpandableItem e1, ExpandableItem e2)
{
return e1.GroupTitle.CompareTo(e2.GroupTitle);
});
// Iterate over each group of items and sort the
// children alphabetically.
foreach (var d in mDataItems)
{
d.ChildItems.Sort(delegate (FMNavigationListItem i1, FMNavigationListItem i2)
{
return i1.DisplayAttributes[0].CompareTo(i2.DisplayAttributes[0]);
});
}
}
public override View GetChildView(int groupPosition, int childPosition, bool isLastChild, View convertView, ViewGroup parent)
{
if (convertView == null)
convertView = mContext.LayoutInflater.Inflate(Resource.Layout.adapter_expandable_listview_listitem, null);
FMNavigationListItem item = mDataItems[groupPosition].ChildItems[childPosition];
convertView.FindViewById<TextView>(Resource.Id.adapter_expandable_listview_listitem_textview1).Text = item.DisplayAttributes[0];
convertView.FindViewById<TextView>(Resource.Id.adapter_expandable_listview_listitem_textview2).Text = item.DisplayAttributes[1];
convertView.FindViewById<TextView>(Resource.Id.adapter_expandable_listview_listitem_textview3).Text = item.DisplayAttributes[2];
ImageButton i = convertView.FindViewById<ImageButton>(Resource.Id.adapter_expandable_listview_listitem_overflow_button);
i.Click += OverflowButtonClicked;
return convertView;
}
private void OverflowButtonClicked(object sender, EventArgs e)
{
Toast.MakeText(
mContext,
"Overflow button clicked!",
ToastLength.Short).Show();
}
public override View GetGroupView(int groupPosition, bool isExpanded, View convertView, ViewGroup parent)
{
if (convertView == null)
convertView = mContext.LayoutInflater.Inflate(Resource.Layout.adapter_expandable_listview_header, null);
// We expand all child objects from the group per default.
// Normal default ist that all children are collapsed.
ExpandableListView listView = (ExpandableListView)parent;
listView.ExpandGroup(groupPosition);
// Set the header title to be the group title.
ExpandableItem item = mDataItems[groupPosition];
convertView.FindViewById<TextView>(Resource.Id.adapter_expandable_listview_header_textview).Text = item.GroupTitle;
return convertView;
}
public override int GroupCount
{
get
{
return mDataItems.Count;
}
}
public override bool HasStableIds
{
get
{
return true;
}
}
public override Java.Lang.Object GetChild(int groupPosition, int childPosition)
{
throw new NotImplementedException();
}
public override long GetChildId(int groupPosition, int childPosition)
{
return childPosition;
}
public override int GetChildrenCount(int groupPosition)
{
return mDataItems[groupPosition].ChildItems.Count;
}
public override bool IsChildSelectable(int groupPosition, int childPosition)
{
return true;
}
public override Java.Lang.Object GetGroup(int groupPosition)
{
throw new NotImplementedException();
}
public override long GetGroupId(int groupPosition)
{
return groupPosition;
}
public FMNavigationListItem ChildAt(int groupPosition, int childPosition)
{
return mDataItems[groupPosition].ChildItems[childPosition];
}
}
/// <summary>
///
/// </summary>
internal class ExpandableItem
{
public string GroupTitle;
public List<FMNavigationListItem> ChildItems;
}
}
あなたが問題を再現することができ、基本的なデモを共有していただけますか？ –
私はまだ実験していくつか試しています。いつでも物事がより明確になるならば、私に知らせます。 – Ivan
@ ElvisXia-MSFTテストプロジェクトソリューションを提供できますか、エラーを再現するコードを投稿する必要がありますか？ – Ivan