android - Xamarin Forms MasterDetail 页面导航导致 Android 崩溃 [致命信号 6 (SIGABRT)，代码 -6]，适用于 iOS 和 UWP

Question

我有一个像下面这样的主细节

public partial class LeaguesMDPage : MasterDetailPage
{
    public LeaguesMDPage()
    {
        InitializeComponent();
        Master = new LeaguesPage();
        Detail = new NavigationPage(new DivisionsPage(new League()));
    }
}

League Page(Master)设计有如下 ListView

    <ListView
    ItemsSource="{Binding Leagues}"
    SelectedItem="{Binding SelectedLeague, Mode=TwoWay}"
    IsPullToRefreshEnabled="True"
    RefreshCommand="{Binding UpdateLeagues}"
    IsRefreshing="{Binding IsBusy}"
    >

后面的代码是

public partial class LeaguesPage : ContentPage
{
    LeaguesViewModel vm;

    public LeaguesPage()
    {
        InitializeComponent();
        BindingContext = vm = new LeaguesViewModel(this);
    }
    protected override void OnAppearing()
    {
        base.OnAppearing();
        vm.UpdateLeagues.Execute(false);   
    }
}

在 LeaguesViewModel 中，我有 SelectedLeague 属性 setter 更新详细信息页面并像这样隐藏 Master

League _SelectedLeague;

public League SelectedLeague
{
    get { return _SelectedLeague; }
    set
    {
        _SelectedLeague = value;
        OnPropertyChanged();
        if (_SelectedLeague != null)
        {
            Debug.WriteLine($"Navigating to DivisionsPage with LeagueID {_SelectedLeague.ID}");
            var mdp = (MasterDetailPage)App.Current.MainPage;
            Device.OnPlatform(                     
                    Android: () => { mdp.IsPresented = false; },
                    iOS: () => { mdp.IsPresented = false; },
                    WinPhone: () => { },
                    Default: () => { mdp.IsPresented = false; }
                );
            mdp.Detail = new NavigationPage(new DivisionsPage(_SelectedLeague));
            _SelectedLeague = null;
        }
    }
}

有时这似乎确实像我希望的那样起作用。它导航到新的 DivisionsPage 并隐藏母版。似乎在 iOS 和 UWP 上运行良好，但它在 Android 上崩溃并出现以下问题

[0:] Server Returned 34 divisions
[0:] Navigating to DivisionsPage with LeagueID 12
[0:] UpdatePoolRankings: Called GetDivisionsAsync
03-23 02:40:52.151 W/Mono    ( 6249): The request to load the assembly System.Core v4.0.0.0 was remapped to v2.0.5.0
03-23 02:40:52.151 D/Mono    ( 6249): Unloading image System.Core.dll [0x99db7700].
03-23 02:40:52.151 D/Mono    ( 6249): Image addref System.Core[0xaec169a0] -> System.Core.dll[0x9d166d00]: 11
03-23 02:40:52.151 D/Mono    ( 6249): Config attempting to parse: 'System.Core.dll.config'.
03-23 02:40:52.151 D/Mono    ( 6249): Config attempting to parse: '/Users/builder/data/lanes/4009/f3074d2c/source/monodroid/builds/install/mono-x86/etc/mono/assemblies/System.Core/System.Core.config'.
03-23 02:40:52.152 W/Mono    ( 6249): The request to load the assembly System.Core v4.0.0.0 was remapped to v2.0.5.0
03-23 02:40:52.152 D/Mono    ( 6249): Unloading image System.Core.dll [0x99db7700].
03-23 02:40:52.152 D/Mono    ( 6249): Image addref System.Core[0xaec169a0] -> System.Core.dll[0x9d166d00]: 12
03-23 02:40:52.152 D/Mono    ( 6249): Config attempting to parse: 'System.Core.dll.config'.
03-23 02:40:52.152 D/Mono    ( 6249): Config attempting to parse: '/Users/builder/data/lanes/4009/f3074d2c/source/monodroid/builds/install/mono-x86/etc/mono/assemblies/System.Core/System.Core.config'.
03-23 02:40:52.383 D/Mono    ( 6249): [0x9b5bf930] hill climbing, change max number of threads 4
[0:] Server Returned 3 divisions
03-23 02:40:52.421 F/        ( 6249): * Assertion at /Users/builder/data/lanes/4009/f3074d2c/source/mono/mono/metadata/sgen-tarjan-bridge.c:1139, condition `xref_count == xref_index' not met
03-23 02:40:52.421 F/libc    ( 6249): Fatal signal 6 (SIGABRT), code -6 in tid 6249 (ClubApp.Droid)
InspectorDebugSession(21): Disposed
InspectorDebugSession(21): HandleTargetEvent: TargetExited

如果需要更多详细信息，请告诉我，谢谢!

Answer 1

我将您的示例更新到最新版本 2.3.4，它可以在 Android 上正常运行。我建议您删除 MasterDetailPage 中的代码并将其更新为以下内容:

<?xml version="1.0" encoding="utf-8" ?>
<MasterDetailPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:local="clr-namespace:ClubApp.Views;assembly=ClubApp"
             xmlns:model="clr-namespace:ClubApp.Models;assembly=ClubApp"
             x:Class="ClubApp.Views.MainMasterDetailPage" 
             Title="MD Page"
             IsPresented="True">
    <MasterDetailPage.Master>
        <local:LeaguesPage />
    </MasterDetailPage.Master>
    <MasterDetailPage.Detail>
        <NavigationPage>
            <x:Arguments>
                <local:DivisionsPage>
                    <x:Arguments>
                        <model:League />
                    </x:Arguments>
                </local:DivisionsPage>
            </x:Arguments>
        </NavigationPage>
    </MasterDetailPage.Detail>
</MasterDetailPage>