AndroidX 迁移后，ListView 未在 OnCreate/OnStart 上显示任何数据 [英] A ListView is not displaying any data on OnCreate/OnStart after AndroidX migration
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问题描述
我有一个应用程序，它只显示数据，直到我在 SearchView 上过滤某些内容.现在，在以下示例中，我将在 Home Activity 和 More Sites Activity (发生错误的地方) 之间切换.
I have an app that is only displaying data until I filter something on a SearchView. Now, in the following example, I'm switching between the Home Activity and the More Sites Activity (where the bug happens).
正如您在我切换到更多站点"活动时所看到的那样，在我过滤"之前，它唯一的 ListView 一直为空.某物.重要的是要强调，在我将应用迁移到 AndroidX 之前，More Sites Activity 过去可以正常工作.
As you could see when I switched to the More Sites activity its only ListView stayed empty until I "filtered" something. It's important to highlight that the More Sites Activity used to work properly before I migrated the app to AndroidX.
这是我当前代码的一部分:
This is part of my current code:
other_ruins.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<androidx.coordinatorlayout.widget.CoordinatorLayout
android:layout_weight="1"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<include layout="@layout/search_container" />
<ListView
android:id="@+id/lstOtherRuins"
android:layout_margin="8dp"
android:layout_height="match_parent"
android:layout_width="match_parent"
android:choiceMode="singleChoice"
android:layout_gravity="left|start" />
</LinearLayout>
</androidx.coordinatorlayout.widget.CoordinatorLayout>
<com.google.android.gms.ads.AdView
android:id="@+id/adView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:adSize="SMART_BANNER"
app:adUnitId="@string/banner_ad_unit_id" />
</LinearLayout>
search_container.xml
<?xml version="1.0" encoding="UTF-8" ?>
<FrameLayout
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/toolbar_container"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<androidx.appcompat.widget.Toolbar
android:id="@+id/toolbar"
app:theme="@style/ToolBarStyle"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="@color/colorPrimary" />
<com.miguelcatalan.materialsearchview.MaterialSearchView
android:id="@+id/search_view"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</FrameLayout>
这是我的 C# 代码，在这两种情况下，我都使用了 UpdateListView 方法:
This is my C# code, and in both cases, I use the UpdateListView method:
protected override void OnStart()
{
base.OnStart();
UpdateListView(AllRuins);
}
private void UpdateListView(List<Row> result)
{
List<IMenuItemsType> item = new();
string prevCountry = "";
foreach (var datum in result)
{
if (datum.Col3 != prevCountry)
{
prevCountry = datum.Col3;
item.Add(new MenuHeaderItem(prevCountry));
}
item.Add(new MenuContentSimpleItem(datum.Col1, datum.Col2, datum.Col3, datum.Col4, datum.Col5));
}
LstOtherRuins.Adapter = new OtherRuinsAdapter(this, item);
}
这是 SearchView 过滤器:
public partial class OtherRuinsActivity
{
public class MaterialSearchViewListener : Java.Lang.Object, MaterialSearchView.IOnQueryTextListener
{
private readonly OtherRuinsActivity OActivity;
public MaterialSearchViewListener(OtherRuinsActivity oActivity)
{
OActivity = oActivity;
}
public bool OnQueryTextChange(string p0)
{
OActivity.CurrentWord = p0;
OActivity.UpdateListView(OActivity.AllRuins.Where(x => x.Col1.ToLower().Contains(p0)).ToList());
return true;
}
public bool OnQueryTextSubmit(string p0)
{
OActivity.CurrentWord = p0;
OActivity.UpdateListView(OActivity.AllRuins.Where(x => x.Col1.ToLower().Contains(p0)).ToList());
return true;
}
}
}
我已经验证并有数据:
这也是我的适配器:
public partial class OtherRuinsAdapter
{
private class OtherRuinsViewHolder : Java.Lang.Object
{
public TextView LblName { get; set; }
public TextView LblLocation { get; set; }
}
}
public partial class OtherRuinsAdapter : ArrayAdapter<IMenuItemsType>
{
public OtherRuinsAdapter(Context context, List<IMenuItemsType> items) : base(context, 0, items)
{
Context1 = context;
Items = items;
Inflater = (LayoutInflater)Context1.GetSystemService(Context.LayoutInflaterService);
}
public override int Count
{
get
{
return Items.Count;
}
}
public Context Context1 { get; set; }
public List<IMenuItemsType> Items { get; set; }
public LayoutInflater Inflater { get; set; }
public LayoutInflater Inflater1 { get => Inflater; set => Inflater = value; }
public override long GetItemId(int position)
{
return position;
}
public override View GetView(int position, View convertView, ViewGroup parent)
{
var inflater = LayoutInflater.From(parent.Context);
OtherRuinsViewHolder holder = null;
var view = convertView;
if (view != null)
{
holder = view.Tag as OtherRuinsViewHolder;
}
if (holder == null)
{
holder = new OtherRuinsViewHolder();
view = inflater.Inflate(Resource.Layout.other_ruins_list, parent, false);
holder.LblName = view.FindViewById<TextView>(Resource.Id.lblName);
holder.LblLocation = view.FindViewById<TextView>(Resource.Id.lblLocation);
view.Tag = holder;
}
IMenuItemsType item = Items[position];
if (item.GetMenuItemsType() == 0)
{
MenuHeaderItem _headerItem = (MenuHeaderItem)item;
view = inflater.Inflate(Resource.Layout.listview_header_item, null);
// user dont click header item
view.Clickable = false;
var headerName = view.FindViewById<TextView>(Resource.Id.txtHeader);
headerName.Text = _headerItem.HeaderText;
}
else if (item.GetMenuItemsType() == 1)
{
MenuContentSimpleItem _contentItem = (MenuContentSimpleItem)item;
if (!string.IsNullOrEmpty(_contentItem.Wiki))
{
holder.LblName.PaintFlags = PaintFlags.UnderlineText;
holder.LblName.SetTextColor(Color.Argb(255, 10, 150, 124));
holder.LblName.Click += LblName_Click;
}
else
{
holder.LblName.PaintFlags = PaintFlags.AntiAlias;
holder.LblName.SetTextColor(Color.Argb(255, 33, 33, 33));
holder.LblName.Click -= LblName_Click;
}
if (!string.IsNullOrEmpty(_contentItem.SubScript))
{
if (Build.VERSION.SdkInt >= BuildVersionCodes.N)
holder.LblName.SetText(Html.FromHtml($"{_contentItem.Title}<sub><small>{_contentItem.SubScript}</small></sub>", FromHtmlOptions.ModeLegacy), BufferType.Spannable);
else
#pragma warning disable CS0618 // Type or member is obsolete
holder.LblName.SetText(Html.FromHtml($"{_contentItem.Title}<sub><small>{_contentItem.SubScript}</small></sub>"), BufferType.Spannable);
#pragma warning restore CS0618 // Type or member is obsolete
}
else
{
holder.LblName.Text = _contentItem.Title;
}
holder.LblLocation.Text = _contentItem.Description;
holder.LblLocation.PaintFlags = PaintFlags.UnderlineText;
holder.LblLocation.Click += LblLocation_Click;
}
return view;
}
private void LblName_Click(object sender, System.EventArgs e)
{
Context1.StartActivity(new Intent(Intent.ActionView, Android.Net.Uri.Parse(new XML2CSharp("OtherRuins.xml").FromXml<Book>().Row.Where(x => x.Col1 == ((TextView)sender).Text).FirstOrDefault().Col4)));
}
private void LblLocation_Click(object sender, System.EventArgs e)
{
Intent mapIntent = new Intent(Intent.ActionView, Android.Net.Uri.Parse($"google.navigation:q={((TextView)sender).Text}, {new XML2CSharp("OtherRuins.xml").FromXml<Book>().Row.Where(x => x.Col2 == ((TextView)sender).Text).FirstOrDefault().Col3}"));
mapIntent.SetPackage("com.google.android.apps.maps");
Context1.StartActivity(mapIntent);
}
}
附注:
看来 GetView 没有因为这个布局而被调用:
It seems the GetView is not being called because of this Layout:
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<include layout="@layout/search_container" />
<ListView
android:id="@+id/lstOtherRuins"
android:layout_margin="8dp"
android:layout_height="match_parent"
android:layout_width="match_parent"
android:choiceMode="singleChoice"
android:layout_gravity="left|start" />
</LinearLayout>
如果我删除 LinearLayout，那么它可以工作，但会生成一个新错误:
If I remove the LinearLayout, then it works but it generates a new bug:
ListView 与 CoordinatorLayout 中的 SearchView 重叠
推荐答案
由于 LinerLayout 包含 ListView.我重新编写了布局，现在它可以正常工作了.
Somehow the GetView method was not called because of a LinerLayout that contains the ListView. I re-wrote the Layout and now it works properly.
other_ruins.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<androidx.coordinatorlayout.widget.CoordinatorLayout
android:layout_weight="1"
android:layout_width="match_parent"
android:layout_height="match_parent">
<include layout="@layout/search_container" />
<ListView
android:id="@+id/lstOtherRuins"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
android:nestedScrollingEnabled="true"
android:layout_margin="8dp"
android:layout_height="match_parent"
android:layout_width="match_parent"
android:choiceMode="singleChoice"
android:layout_below="@id/toolbar_container"
android:layout_gravity="left|start" />
</androidx.coordinatorlayout.widget.CoordinatorLayout>
<com.google.android.gms.ads.AdView
android:id="@+id/adView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:adSize="SMART_BANNER"
app:adUnitId="@string/banner_ad_unit_id" />
</LinearLayout>
此外，我需要通过添加 AppBarLayout 来更改容器，因为它是重叠的.
Also, I needed to change the container by adding the AppBarLayout because it was being overlapped.
search_container.xml:
<?xml version="1.0" encoding="UTF-8" ?>
<com.google.android.material.appbar.AppBarLayout
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/toolbar_container"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<FrameLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<androidx.appcompat.widget.Toolbar
android:id="@+id/toolbar"
app:theme="@style/ToolBarStyle"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="@color/colorPrimary" />
<com.miguelcatalan.materialsearchview.MaterialSearchView
android:id="@+id/search_view"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</FrameLayout>
</com.google.android.material.appbar.AppBarLayout>
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