【发布时间】：2019-03-01 23:03:47
【问题描述】：
我有一个带有模板标题的列表视图，每一行都是一个自定义控件，它为 Android 呈现一个回收器视图。
有时当我更新列表绑定到的可观察集合时，我会收到以下内容
09-26 09:58:12.759 F/ (19698): * 断言在 /Users/builder/data/lanes/6090/86d33f45/source/monodroid/external/xamarin-android/external/mono/mono/metadata /sgen-tarjan-bridge.c:1140，条件
xref_count == xref_index' not met 09-26 09:58:12.764 F/libc (19698): Fatal signal 6 (SIGABRT), code -6 in tid 19822 (Thread Pool Wor), pid 19698 (houseofcode.Mir) 09-26 09:58:12.914 I/crash_dump32(20062): obtaining output fd from tombstoned, type: kDebuggerdTombstone 09-26 09:58:12.916 I//system/bin/tombstoned( 1483): received crash request for pid 19698 09-26 09:58:12.920 I/crash_dump32(20062): performing dump of process 19698 (target tid = 19822) 09-26 09:58:12.922 F/DEBUG (20062): *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** 09-26 09:58:12.922 F/DEBUG (20062): Build fingerprint: 'google/sdk_gphone_x86/generic_x86:8.1.0/OSM1.180201.007/4586646:user/release-keys' 09-26 09:58:12.922 F/DEBUG (20062): Revision: '0' 09-26 09:58:12.922 F/DEBUG (20062): ABI: 'x86' 09-26 09:58:12.922 F/DEBUG (20062): pid: 19698, tid: 19822, name: Thread Pool Wor >>> io.houseofcode.Mir <<< 09-26 09:58:12.922 F/DEBUG (20062): signal 6 (SIGABRT), code -6 (SI_TKILL), fault addr -------- 09-26 09:58:12.923 F/DEBUG (20062): Abort message: '* Assertion at /Users/builder/data/lanes/6090/86d33f45/source/monodroid/external/xamarin-android/external/mono/mono/metadata/sgen-tarjan-bridge.c:1140, conditionxref_count == xref_index' 未满足 09-26 09:58:12.923 F/调试（20062）：' 09-26 09:58:12.923 F/DEBUG (20062): eax 00000000 ebx 00004cf2 ecx 00004d6e edx 00000006 09-26 09:58:12.923 F/DEBUG (20062): esi 00000000 edi 00004cf2 09-26 09:58:12.923 F/DEBUG (20062): xcs 00000073 xds 0000007b xes 0000007b xfs 0000003b xss 0000007b 09-26 09:58:12.923 F/DEBUG (20062): eip b040dac4 ebp 00000000 esp 7d0fdd28 标志 00200286 09-26 09:58:12.926 F/调试 (20062): 09-26 09:58:12.926 F/DEBUG (20062)：回溯： 09-26 09:58:12.926 F/DEBUG (20062): #00 pc 00000ac4 [vdso:b040d000] (__kernel_vsyscall+16) 09-26 09:58:12.926 F/DEBUG (20062): #01 pc 0001edf8 /system/lib/libc.so (syscall+40) 09-26 09:58:12.926 F/DEBUG (20062): #02 pc 0001f073 /system/lib/libc.so (abort+115) 09-26 09:58:12.926 F/DEBUG (20062): #03 pc 00295345 /data/app/Mono.Android.DebugRuntime-FonMYGn1d4jnoxtVxgxnRg==/lib/x86/libmonosgen-32bit-2.0.so 09-26 09:58:13.547 W/zygote (1593): kill(-14436, 9) failed: No such process 09-26 09:58:13.547 I/zygote (1593): 1ms 内成功杀死进程 cgroup uid 10053 pid 14436 09-26 09:58:13.549 I/ActivityManager（1593）：进程 com.google.android.apps.docs（pid 14436）已死亡：cch+6CEM 09-26 09:58:13.684 W/Looper (1593): 调度在 android.ui 上花费了 112 毫秒，h=Handler (com.android.server.am.ActivityManagerService$UiHandler) {d9bb478} cb=null msg=53 09-26 09:58:13.853 E//system/bin/tombstoned（1483）：墓碑写入：/data/tombstones/tombstone_00 09-26 09:58:13.883 I/BootReceiver（1593）：将 /data/tombstones/tombstone_00 复制到 DropBox (SYSTEM_TOMBSTONE) 09-26 09:58:13.914 W/ActivityManager（1593）：强制完成活动 io.houseofcode.Mir/md558c489633a57fe94a7e603acc8e0c63b.MainActivity 09-26 09:58:13.973 W/InputDispatcher（1593）：通道'81391ff io.houseofcode.Mir/md558c489633a57fe94a7e603acc8e0c63b.MainActivity（服务器）'~消费者关闭输入通道或发生错误。事件=0xd 09-26 09:58:13.973 E/InputDispatcher(1593): 通道 '81391ff io.houseofcode.Mir/md558c489633a57fe94a7e603acc8e0c63b.MainActivity (server)' ~ 通道已不可恢复地损坏，将被处理！ 09-26 09:58:13.981 I/Zygote (1466): 进程 19698 因信号 (6) 而退出 09-26 09:58:13.992 I/WindowManager(1593): WIN DEATH: Window{81391ff u0 io.houseofcode.Mir/md558c489633a57fe94a7e603acc8e0c63b.MainActivity} 09-26 09:58:13.992 W/InputDispatcher（1593）：试图取消注册已经未注册的输入通道'81391ff io.houseofcode.Mir/md558c489633a57fe94a7e603acc8e0c63b.MainActivity（服务器）' 09-26 09:58:14.005 W/ActivityManager（1593）：暂停期间抛出异常 09-26 09:58:14.005 W/ActivityManager（1593）：android.os.DeadObjectException 09-26 09:58:14.005 W/ActivityManager（1593）：在 android.os.BinderProxy.transactNative（本机方法） 09-26 09:58:14.005 W/ActivityManager（1593）：在 android.os.BinderProxy.transact（Binder.java:764） 09-26 09:58:14.005 W/ActivityManager（1593）：在 android.app.IApplicationThread$Stub$Proxy.schedulePauseActivity（IApplicationThread.java:1079） 09-26 09:58:14.005 W/ActivityManager（1593）：在 com.android.server.am.ActivityStack.startPausingLocked（ActivityStack.java:1347） 09-26 09:58:14.005 W/ActivityManager（1593）：在 com.android.server.am.ActivityStack.finishActivityLocked（ActivityStack.java:3779） 09-26 09:58:14.005 W/ActivityManager（1593）：在 com.android.server.am.ActivityStack.finishActivityLocked（ActivityStack.java:3721） 09-26 09:58:14.005 W/ActivityManager（1593）：在 com.android.server.am.ActivityStack.finishTopRunningActivityLocked（ActivityStack.java:3602） 09-26 09:58:14.005 W/ActivityManager（1593）：在 com.android.server.am.ActivityStackSupervisor.finishTopRunningActivityLocked（ActivityStackSupervisor.java:2124） 09-26 09:58:14.005 W/ActivityManager（1593）：在 com.android.server.am.AppErrors.handleAppCrashLocked（AppErrors.java:668） 09-26 09:58:14.005 W/ActivityManager（1593）：在 com.android.server.am.AppErrors.makeAppCrashingLocked（AppErrors.java:500） 09-26 09:58:14.005 W/ActivityManager（1593）：在 com.android.server.am.AppErrors.crashApplicationInner（AppErrors.java:376） 09-26 09:58:14.005 W/ActivityManager（1593）：在 com.android.server.am.AppErrors.crashApplication（AppErrors.java:321） 09-26 09:58:14.005 W/ActivityManager（1593）：在 com.android.server.am.ActivityManagerService.handleApplicationCrashInner（ActivityManagerService.java:14375） 09-26 09:58:14.005 W/ActivityManager（1593）：在 com.android.server.am.NativeCrashListener$NativeCrashReporter.run（NativeCrashListener.java:85） 09-26 09:58:14.015 D/ConnectivityService(1593): ConnectivityService NetworkRequestInfo binderDied(NetworkRequest [ LISTEN id=68, [ Capabilities: INTERNET&NOT_RESTRICTED&TRUSTED&NOT_VPN&VALIDATED&FOREGROUND] ], android.os.BinderProxy@8f5a243) 09-26 09:58:14.025 E/lowmemorykiller（1404）：打开 /proc/19698/oom_score_adj 时出错；错误号=2 09-26 09:58:14.067 I/ActivityManager(1593): Process io.houseofcode.Mir (pid 19698) has dead: vis +99TOP 09-26 09:58:14.069 W/zygote (1593): kill(-19698, 9) failed: No such process 09-26 09:58:14.069 I/zygote (1593): 在 1ms 内成功杀死进程 cgroup uid 10108 pid 19698 09-26 09:58:14.100 D/gralloc_ranchu（1395）：gralloc_alloc：创建大小为 8298496 的 ashmem 区域 09-26 09:58:14.108 W/ActivityManager（1593）：setHasOverlayUi 在未知 pid 上调用：19698 09-26 09:58:14.130 I/ActivityManager(1593): 显示包 io.houseofcode.Mir u0 的崩溃对话框
这是我的列表视图
<ListView x:Name="lstVideos" SeparatorVisibility="None" ItemsSource="{Binding Videos}" HasUnevenRows="true">
<ListView.Header>
<Grid x:Name="vwFeatured" VerticalOptions="StartAndExpand" HeightRequest="180">
<Grid.GestureRecognizers>
<TapGestureRecognizer Command="{Binding ShowVideoCommand}" CommandParameter="{Binding FeaturedVideo}"></TapGestureRecognizer>
</Grid.GestureRecognizers>
<Image x:Name="imgFeatured" BackgroundColor="DimGray" Aspect="Fill" Source="{Binding FeaturedVideo.Thumbnail}"
VerticalOptions="FillAndExpand" HorizontalOptions="FillAndExpand">
</Image>
<Image Source="Play" IsVisible="{Binding FeaturedVideo.FullyDownloaded}" VerticalOptions="Center" HorizontalOptions="Center">
</Image>
<Label Text="Loading..." FontSize="Medium" TextColor="White" IsVisible="{Binding FeaturedVideo.FullyDownloaded, Converter={StaticResource InverseBoolConverter}}"
VerticalOptions="Center" HorizontalOptions="Center"></Label>
</Grid>
</ListView.Header>
<ListView.ItemTemplate>
<DataTemplate>
<controls2:TransparentCell>
<StackLayout Margin="0, 10">
<StackLayout HorizontalOptions="Fill" Orientation="Horizontal">
<Label Text="{Binding SectionName}" VerticalOptions="Fill" VerticalTextAlignment="Center" HorizontalOptions="Start" Style="{StaticResource SectionHeaderStyle}" Margin="10,10">
</Label>
<Label Text="{Binding VideoCount, StringFormat='{0:D} videos'}" VerticalTextAlignment="Center" VerticalOptions="Fill" HorizontalOptions="EndAndExpand" Style="{StaticResource VideoCountStyle}" Margin="10,10">
</Label>
</StackLayout>
<controls:XfGridView x:Name="vwVideos" ItemsSource="{Binding VideoData}" Orientation="Horizontal" ItemTemplate="{StaticResource videoTemplate}"
ColumnSpacing="15" RowSpacing="5" ItemWidth="145" ItemHeight="120">
</controls:XfGridView>
</StackLayout>
</controls2:TransparentCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
这是我的自定义渲染器
public class XfGridRenderer : ViewRenderer<XfGridView, RecyclerView>
{
protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
{
if (Element.ItemsSource != null)
{
int count = 0;
foreach (var item in Element.ItemsSource)
count++;
}
var recyclerView = new RecyclerView(Context);
int orientation = (Element.Orientation == Controls.GridOrientation.Horizontal) ? OrientationHelper.Horizontal : OrientationHelper.Vertical;
recyclerView.SetLayoutManager(new GridLayoutManager(Context, Element.NoOfColumns, orientation, false));
recyclerView.AddItemDecoration(new RecyclerItemDecoration((int)Element.RowSpacing, (int)Element.ColumnSpacing, (int)Element.NoOfColumns, orientation));
SetNativeControl(recyclerView);
var adapter = new RecycleViewAdapter(Element);
Control.SetAdapter(adapter);
}
protected override void OnElementChanged(ElementChangedEventArgs<XfGridView> e)
{
base.OnElementChanged(e);
if ((Element.Orientation == Controls.GridOrientation.Vertical))
Element.WidthRequest = Element.NoOfColumns * Element.ItemWidth;
else
Element.HeightRequest = Element.NoOfColumns * Element.ItemHeight;
}
}
public class RecycleViewAdapter : RecyclerView.Adapter
{
private readonly XfGridView _view;
private readonly IList _dataSource;
public override int ItemCount => (_dataSource != null ? _dataSource.Count : 0);
public override long GetItemId(int position)
{
return position;
}
public RecycleViewAdapter(XfGridView view)
{
_view = view;
_dataSource = view.ItemsSource?.Cast<object>()?.ToList();
HasStableIds = true;
}
public override void OnBindViewHolder(RecyclerView.ViewHolder holder, int position)
{
var item = (RecycleViewHolder)holder;
var dataContext = _dataSource[position];
item.SetBindingItems(dataContext, _view);
}
public override void OnViewAttachedToWindow(Java.Lang.Object holder)
{
base.OnViewAttachedToWindow(holder);
var item = (RecycleViewHolder)holder;
item.UpdateUi();
}
public override RecyclerView.ViewHolder OnCreateViewHolder(ViewGroup parent, int viewType)
{
var contentFrame = new FrameLayout(parent.Context)
{
LayoutParameters = new FrameLayout.LayoutParams(ViewGroup.LayoutParams.WrapContent,
ViewGroup.LayoutParams.WrapContent)
{
Height = (int)(_view.ItemHeight * Resources.System.DisplayMetrics.Density),
Width = (int)(_view.ItemWidth * Resources.System.DisplayMetrics.Density)
}
};
contentFrame.DescendantFocusability = DescendantFocusability.BeforeDescendants;
var viewHolder = new RecycleViewHolder(contentFrame);
return viewHolder;
}
}
public class RecycleViewHolder : RecyclerView.ViewHolder
{
private ViewCell _viewCell;
private object _dataContext;
private XfGridView _view;
public RecycleViewHolder(Android.Views.View itemView) : base(itemView)
{
ItemView = itemView;
}
public void SetBindingItems(object dataContext, XfGridView view)
{
_dataContext = dataContext;
_view = view;
}
public void UpdateUi()
{
if (_dataContext != null)
{
var dataTemplate = _view.ItemTemplate;
var selector = dataTemplate as DataTemplateSelector;
if (selector != null)
{
var template = selector.SelectTemplate(_dataContext, _view.Parent);
_viewCell = template.CreateContent() as ViewCell;
}
else
{
_viewCell = dataTemplate?.CreateContent() as ViewCell;
}
}
var contentLayout = (FrameLayout)ItemView;
_viewCell.BindingContext = _dataContext;
_viewCell.Parent = _view;
var metrics = Resources.System.DisplayMetrics;
var height = (int)((_view.ItemWidth + _viewCell.View.Margin.Top + _viewCell.View.Margin.Bottom) * metrics.Density);
var width = (int)((_view.ItemWidth + _viewCell.View.Margin.Left + _viewCell.View.Margin.Right) * metrics.Density);
_viewCell.View.Layout(new Rectangle(0, 0, _view.ItemWidth, _view.ItemHeight));
var layoutParams = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.WrapContent, ViewGroup.LayoutParams.WrapContent)
{
Height = height,
Width = width
};
if (Platform.GetRenderer(_viewCell.View) == null)
{
Platform.SetRenderer(_viewCell.View, Platform.CreateRenderer(_viewCell.View));
}
var renderer = Platform.GetRenderer(_viewCell.View);
var viewGroup = renderer.View;
viewGroup.LayoutParameters = layoutParams;
viewGroup.Layout(0, 0, (int)_view.ItemWidth, (int)_view.ItemHeight);
contentLayout.RemoveAllViews();
contentLayout.AddView(viewGroup);
}
}
public class RecyclerItemDecoration : RecyclerView.ItemDecoration
{
private int _rowSpacing;
private int _colSpacing;
private int _noOfColumns;
private int _orientation;
public RecyclerItemDecoration(int rowSpacing, int colSpacing, int colNo, int orientation)
{
_rowSpacing = (int)(rowSpacing * Resources.System.DisplayMetrics.Density);
_colSpacing = (int)(colSpacing * Resources.System.DisplayMetrics.Density);
_noOfColumns = colNo;
_orientation = orientation;
}
public override void GetItemOffsets(Rect outRect, Android.Views.View view, RecyclerView parent, RecyclerView.State state)
{
base.GetItemOffsets(outRect, view, parent, state);
outRect.Right = _colSpacing;
outRect.Bottom = _rowSpacing;
int position = parent.GetChildLayoutPosition(view);
if (_orientation == OrientationHelper.Vertical)
{
if (position < _noOfColumns)
{
outRect.Top = _rowSpacing;
}
else
{
outRect.Top = 0;
}
if ((position % _noOfColumns) == 0)
{
outRect.Left = _colSpacing;
}
else
{
outRect.Left = _colSpacing / 2;
}
}
else
{
if ((position % _noOfColumns) == 0)
{
outRect.Top = _rowSpacing;
}
else
{
outRect.Top = _rowSpacing / 2;
}
if (position < _noOfColumns)
{
outRect.Left = _colSpacing;
}
else
{
outRect.Left = 0;
}
}
}
}
【问题讨论】：