如何使用MvvmCross创建MasterDetailPage? [英] How to create a MasterDetailPage using MvvmCross?

问题描述

我正在尝试使用MvvmCross开发Xamarin.Forms应用，并且我想使用Hamburguer菜单(MasterDetailPage)，但我不知道该怎么做.我尝试了不同的方法，搜索了教程和示例，但是没有成功.谁能帮我?

I'm trying to develop a Xamarin.Forms app using MvvmCross and I'd like to use a Hamburguer Menu (MasterDetailPage), but I don't know how to do it. I tried different ways, searched for tutorials and samples, but I don't had success. Can anyone help me?

推荐答案

如您在此处看到的

As you can see here MvvmCross Playground, you should create first a RootViewModel, MenuViewModel, and FirstViewModel for example. Then create and a RootPage, MenuPage and FirstPage on your UI folder.

您的RootViewModel应该看起来像这样:

Your RootViewModel should look like this:

public class RootViewModel : BaseViewModel
{
    private readonly IMvxNavigationService _navigationService;
    public RootViewModel(IMvxNavigationService navigationService)
    {
        _navigationService = navigationService;
    }

    public override void ViewAppearing()
    {
        base.ViewAppearing();

        MvxNotifyTask.Create(async ()=> await this.InitializeViewModels();
    }

    private async Task InitializeViewModels()
    {
        await _navigationService.Navigate<MenuViewModel>();
        await _navigationService.Navigate<FirstViewModel>();
    }
}

编辑:我将导航移至异步任务，以避免使用异步空值.

edit: I move the navigation to an async task to avoid using async void.

xaml RootPage必须实现MvxMasterDetailPage:

The xaml RootPage must implement MvxMasterDetailPage:

<?xml version="1.0" encoding="UTF-8"?>
<views:MvxMasterDetailPage x:TypeArguments="viewModels:RootViewModel"
    xmlns="http://xamarin.com/schemas/2014/forms"
    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
    xmlns:views="clr-namespace:MvvmCross.Forms.Views;assembly=MvvmCross.Forms"
    xmlns:mvx="clr-namespace:MvvmCross.Forms.Bindings;assembly=MvvmCross.Forms"
    xmlns:viewModels="clr-namespace:yournamespace.Core.ViewModels"
    x:Class="yournamespace.UI.Views.RootPage"
    Icon="hamburger.png">
</views:MvxMasterDetailPage>

和后面的c#代码使用演示者是这样的:

and c# code behind use the presenter like this:

[MvxMasterDetailPagePresentation(MasterDetailPosition.Root, WrapInNavigationPage = false)]
public partial class RootPage : MvxMasterDetailPage<RootViewModel>
{
    public RootPage()
    {
        InitializeComponent();
    }

    protected override void OnAppearing()
    {
        base.OnAppearing();
    }
}

MenuPage必须是普通的MvxContentPage，并且在演示者的菜单页上的背后是c#代码:

MenuPage must be normal MvxContentPage and c# code behind implement on menu page the presenter:

[MvxMasterDetailPagePresentation(MasterDetailPosition.Master)]

并且FirstPage也是MvxContentPage，所有详细信息页面也必须是:

And FirstPage are MvxContentPage too and all the detail pages must be:

[MvxMasterDetailPagePresentation(MasterDetailPosition.Detail, NoHistory = true)]

在主页面中的所有页面上添加无历史记录"，以防止向后浏览错误.

Add the no history to all pages in master detail to prevent navigation back bug.

我忘记了，有个bug使得导航后导航菜单无法关闭，可能它们将在MvvmCross的版本6上修复，要修复此错误，现在必须将其粘贴到导航中执行导航之前的任务:

edit: i forgot, there's a bug that make menu doesn't close after navigate, probably they'll fix on version 6 of MvvmCross, to fix it now you must paste this in your navigation task before execute the navigation:

if(Application.Current.MainPage is MasterDetailPage masterDetailPage)
{
    masterDetailPage.IsPresented = false; 
}
else if(Application.Current.MainPage is NavigationPage navigationPage && navigationPage.CurrentPage is MasterDetailPage nestedMasterDetail)
{
    nestedMasterDetail.IsPresented = false;
}

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