RecyclerView复选框在Xamarin MVVMCross模式 [英] RecyclerView Checkbox in MVVMCross pattern in Xamarin

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本文介绍了RecyclerView复选框在Xamarin MVVMCross模式的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我有以下。 axmls 这基本上是一个 recyclerview ，其中包含一个TextView和复选框。我可以不能够弄清楚如何使用复选框互动，删除 mvvmcross 设计选定的项目。

fragment_example_recyclerview.axml 

 ＆LT;？XML版本=1.0编码=UTF-8＆GT？;
＆LT; android.support.design.widget.CoordinatorLayout
的xmlns：机器人=htt​​p://schemas.android.com/apk/res/android
XMLNS：地方=htt​​p://schemas.android.com/apk/res-auto
机器人：layout_width =match_parent
机器人：layout_height =match_parent＆GT;
＆LT;包括
    布局=@布局/ toolbar_actionbar/＆GT;
    ＆LT; MvxRecyclerView
        机器人：ID =@ + ID / my_recycler_view
        机器人：滚动条=垂直
        机器人：layout_width =match_parent
        机器人：layout_height =match_parent
        本地：MvxItemTemplate =@布局/ listitem_recyclerviewexample
        本地：MvxBind =ItemsSource的项目;项目单击ItemSelected/＆GT;
＆LT; /android.support.design.widget.CoordinatorLayout>

listitem_recyclerviewexample.xml 

 ＆LT;？XML版本=1.0编码=UTF-8＆GT？;
＆LT; LinearLayout中的xmlns：机器人=htt​​p://schemas.android.com/apk/res/android
XMLNS：地方=htt​​p://schemas.android.com/apk/res-auto
机器人：方向=横向
机器人：layout_width =FILL_PARENT
机器人：layout_height =FILL_PARENT＆GT;＆LT;复选框机器人：ID =@ + ID / checkbox_meat
    机器人：layout_width =WRAP_CONTENT
    机器人：layout_height =WRAP_CONTENT/＆GT;＆LT;的TextView
    机器人：ID =@ + ID / innerText属性
    机器人：layout_width =FILL_PARENT
    机器人：layout_height =WRAP_CONTENT
    机器人：layout_marginRight =5DP
    机器人：填充=10dp
    本地：MvxBind =TEXT标题/＆GT;

ExampleViewPagerViewModel.cs 

 使用MvvmCross.Core.ViewModels;命名空间Example.Core.ViewModels
{
    公共类ExampleViewPagerViewModel
        ：MvxViewModel
    {
        公共RecyclerViewModel回收站{搞定;私人集; }        公共ExampleViewPagerViewModel（）
        {
            回收=新RecyclerViewModel（）;
        }
    }
}

RecyclerViewModel.cs 

 使用MvvmCross.Core.ViewModels;
使用系统;
使用System.Collections.ObjectModel;
使用System.Threading.Tasks;
使用System.Windows.Input;命名空间Example.Core.ViewModels
{    公共类RecyclerViewModel
        ：MvxViewModel
    {
        私人列表项_selectedItem;        公共RecyclerViewModel（）
        {
            项目=新的ObservableCollection＆LT;＆列表项GT; {
                新的ListItem {标题=A}，
                新的ListItem {标题=B}，
                新的ListItem {标题=C}，
                新的ListItem {标题=D}，
                新的ListItem {标题=E}
            };
        }        私人的ObservableCollection＆LT;＆列表项GT; _items;        公众的ObservableCollection＆LT;＆列表项GT;项目
        {
            {返回_items; }
            组
            {
                _items =价值;
                RaisePropertyChanged（（）=＆GT;产品）;
            }
        }        公共列表项的SelectedItem
        {
            {返回_selectedItem; }
            组
            {
                _selectedItem =价值;
                RaisePropertyChanged（（）=＆GT;的SelectedItem）;
            }
        }        公共虚拟的ICommand ItemSelected
        {
            得到
            {
                返回新MvxCommand＆LT;＆列表项GT;（项目=＆GT;
                {
                    的SelectedItem =项目;
                }）;
            }
        }
    }
}

ExampleViewPagerFragment.cs 

 使用System.Collections.Generic;
使用Android.OS;
使用Android.Runtime;
使用Android.Support.Design.Widget;
使用Android.Support.V4.View;
使用Android.Views;
使用Example.Core.ViewModels;
使用MvvmCross.Droid.Support.V4;
使用MvvmCross.Droid.Support.V7.Fragging.Attributes;命名空间Example.Droid.Fragments
{
    [MvxFragment（typeof运算（MainViewModel），Resource.Id.content_frame）
    [寄存器（example.droid.fragments.ExampleViewPagerFragment）]
    公共类ExampleViewPagerFragment：BaseFragment＆LT; ExampleViewPagerViewModel＆GT;
    {
        保护覆盖INT FragmentId =＆GT; Resource.Layout.fragment_example_viewpager;        公众覆盖查看OnCreateView（LayoutInflater充气器，容器的ViewGroup，捆绑savedInstanceState）
        {
            VAR视图= base.OnCreateView（充气器，容器，savedInstanceState）;            VAR viewPager = view.FindViewById＆LT; ViewPager＆GT;（Resource.Id.viewpager）;
            如果（viewPager！= NULL）
            {                VAR VM =新RecyclerViewModel（）;
                VAR碎片=新的List＆LT; MvxFragmentPagerAdapter.FragmentInfo＆GT;（）;
                的for（int i = 0; I＆LT; vm.Items.Count;我++）
                {
                    fragments.Add（新MvxFragmentPagerAdapter.FragmentInfo（RecyclerView+（I + 1）的ToString（）的typeof（RecyclerViewFragment）的typeof（RecyclerViewModel）））;
                }                viewPager.Adapter =新Mv​​xFragmentPagerAdapter（活动，ChildFragmentManager，片段）;
            }            VAR tabLayout = view.FindViewById＆LT; TabLayout＆GT;（Resource.Id.tabs）;
            tabLayout.SetupWithViewPager（viewPager）;            返回视图。
        }
    }
}

RecyclerViewFragment.cs 

 使用系统;
使用Android.OS;
使用Android.Runtime;
使用Android.Support.Design.Widget;
使用Android.Support.V7.Widget;
使用Android.Views;
使用Android.Widget;
使用MvvmCross.Platform.WeakSubscription;
使用MvvmCross.Binding.Droid.BindingContext;
使用MvvmCross.Droid.Support.V7.Fragging.Fragments;
使用MvvmCross.Droid.Support.V7.RecyclerView;
使用MvvmCross.Droid.Support.V4;
使用Example.Core.ViewModels;
使用MvvmCross.Droid.Support.V7.Fragging.Attributes;命名空间Example.Droid.Fragments
{
    [MvxFragment（typeof运算（MainViewModel），Resource.Id.content_frame）
    [寄存器（example.droid.fragments.RecyclerViewFragment）]
    公共类RecyclerViewFragment：MvxFragment＆LT; RecyclerViewModel＆GT;
    {
        私人IDisposable的_itemSelectedToken;        公众覆盖查看OnCreateView（LayoutInflater充气器，容器的ViewGroup，捆绑savedInstanceState）
        {
            VAR忽略= base.OnCreateView（充气器，容器，savedInstanceState）;            VAR视图= this.BindingInflate（Resource.Layout.fragment_recyclerview，NULL）;            VAR recyclerView = view.FindViewById＆LT; MvxRecyclerView＆GT;（Resource.Id.my_recycler_view）;
            如果（recyclerView！= NULL）
            {
                recyclerView.HasFixedSize =真;
                VAR的layoutManager =新LinearLayoutManager（活动）;
                recyclerView.SetLayoutManager（的layoutManager）;
            }            _itemSelectedToken = ViewModel.WeakSubscribe（（）=＆GT; ViewModel.SelectedItem，
                （发件人，参数）=＆GT; {
                    如果（ViewModel.SelectedItem！= NULL）
                        Toast.MakeText（活动，
                            $选择：{} ViewModel.SelectedItem.Title
                            ToastLength.Short）.Show（）;
                }）;            VAR appBar = Activity.FindViewById＆LT; AppBarLayout＆GT;（Resource.Id.appbar）;
            如果（appBar！= NULL）
                appBar.OffsetChanged + =（发件人，参数）=＆GT; swipeToRefresh.Enabled = args.VerticalOffset == 0;            返回视图。
        }        公共覆盖无效OnDestroyView（）
        {
            base.OnDestroyView（）;
            _itemSelectedToken.Dispose（）;
            _itemSelectedToken = NULL;
        }
    }
}

下面是我目前看来，在那里我可以选择并取消该复选框，但我不知道怎么才能删除所选项目处理这个select事件。

在这里输入的形象描述

更新：

不过，我不明白如何处理选中的复选框，以便删除操作。

 类的ListItem
{
    公众诠释标识{搞定;组; }
    公共字符串文本{搞定;组; }
    私人布尔_isChecked;    公共BOOL器isChecked
    {
        {返回_isChecked; }
        组
        {
            _isChecked =价值;
        }
    }
} 公共类MyViewModel：MvxViewModel
 {    私人的ObservableCollection＆LT; MyListViewModel＆GT; _myListViews;    公众的ObservableCollection＆LT; MyListViewModel＆GT; MyListViews
    {
        {返回_myListViews; }
        组
        {
            _myListViews =价值;
            RaisePropertyChanged（（）=＆GT; MyListViews）;
        }
    }
    公共无效初始化（字符串MYID）
    {
         清单＆LT;＆列表项GT; allListItems =新的List＆LT;＆列表项GT;（）;
         allListItems = _myService.GetAllItems（身份识别码）;
         的foreach（在allListItems VAR MYTEST）
         {
           _myListViews.Add（MyListViewModel.CreateViewModel（MYTEST））;
         }
      }
   }


解决方案

添加器isChecked 属性设置为列表项类并将其绑定到里面 listitem_recyclerviewexample 的复选框，这样的：地方：MvxBind =经过器isChecked

如果您的类看起来是这样的，你应该能够找出哪些项目检查，并选中。

 类的ListItem
{
    公众诠释标识{搞定;组; }
    公共字符串文本{搞定;组; }
    私人布尔_isChecked;    公共BOOL器isChecked
    {
        {返回_isChecked; }
        组
        {
            _isChecked =价值;
        }
    }
}

I have the following .axmls which is basically a recyclerview which contains a textview and checkbox. I could not able to figure out how to interact with checkbox to delete the selected item in mvvmcross design.

fragment_example_recyclerview.axml

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout  
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:local="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<include
    layout="@layout/toolbar_actionbar" />
    <MvxRecyclerView
        android:id="@+id/my_recycler_view"
        android:scrollbars="vertical"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        local:MvxItemTemplate="@layout/listitem_recyclerviewexample"
        local:MvxBind="ItemsSource Items; ItemClick ItemSelected" />
</android.support.design.widget.CoordinatorLayout>

listitem_recyclerviewexample.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:local="http://schemas.android.com/apk/res-auto"
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="fill_parent">

<CheckBox android:id="@+id/checkbox_meat"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"/>

<TextView
    android:id="@+id/innerText"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_marginRight="5dp"
    android:padding="10dp"
    local:MvxBind="Text Title" />

ExampleViewPagerViewModel.cs

using MvvmCross.Core.ViewModels;

namespace Example.Core.ViewModels
{
    public class ExampleViewPagerViewModel
        : MvxViewModel
    {
        public RecyclerViewModel Recycler { get; private set; }

        public ExampleViewPagerViewModel()
        {
            Recycler = new RecyclerViewModel();
        }
    }
}

RecyclerViewModel.cs

using MvvmCross.Core.ViewModels;
using System;
using System.Collections.ObjectModel;
using System.Threading.Tasks;
using System.Windows.Input;

namespace Example.Core.ViewModels
{

    public class RecyclerViewModel
        : MvxViewModel
    {
        private ListItem _selectedItem;

        public RecyclerViewModel()
        {
            Items = new ObservableCollection<ListItem> {
                new ListItem { Title = "A" },
                new ListItem { Title = "B" },
                new ListItem { Title = "C" },
                new ListItem { Title = "D" },
                new ListItem { Title = "E" }
            };
        }

        private ObservableCollection<ListItem> _items;

        public ObservableCollection<ListItem> Items
        {
            get { return _items; }
            set
            {
                _items = value;
                RaisePropertyChanged(() => Items);
            }
        }

        public ListItem SelectedItem
        {
            get { return _selectedItem; }
            set
            {
                _selectedItem = value;
                RaisePropertyChanged(() => SelectedItem);
            }
        }

        public virtual ICommand ItemSelected
        {
            get
            {
                return new MvxCommand<ListItem>(item =>
                {
                    SelectedItem = item;
                });
            }
        }        
    }
}

ExampleViewPagerFragment.cs

using System.Collections.Generic;
using Android.OS;
using Android.Runtime;
using Android.Support.Design.Widget;
using Android.Support.V4.View;
using Android.Views;
using Example.Core.ViewModels;
using MvvmCross.Droid.Support.V4;
using MvvmCross.Droid.Support.V7.Fragging.Attributes;

namespace Example.Droid.Fragments
{
    [MvxFragment(typeof (MainViewModel), Resource.Id.content_frame)]
    [Register("example.droid.fragments.ExampleViewPagerFragment")]
    public class ExampleViewPagerFragment : BaseFragment<ExampleViewPagerViewModel>
    {
        protected override int FragmentId => Resource.Layout.fragment_example_viewpager;

        public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
        {
            var view = base.OnCreateView(inflater, container, savedInstanceState);

            var viewPager = view.FindViewById<ViewPager>(Resource.Id.viewpager);
            if (viewPager != null)
            {

                var vm = new RecyclerViewModel();
                var fragments = new List<MvxFragmentPagerAdapter.FragmentInfo>();
                for(int i = 0; i < vm.Items.Count; i++)
                {
                    fragments.Add(new MvxFragmentPagerAdapter.FragmentInfo("RecyclerView " + (i+1).ToString(), typeof (RecyclerViewFragment),typeof (RecyclerViewModel)));
                }

                viewPager.Adapter = new MvxFragmentPagerAdapter(Activity, ChildFragmentManager, fragments);
            }

            var tabLayout = view.FindViewById<TabLayout>(Resource.Id.tabs);
            tabLayout.SetupWithViewPager(viewPager);

            return view;
        }
    }
}

RecyclerViewFragment.cs

using System;
using Android.OS;
using Android.Runtime;
using Android.Support.Design.Widget;
using Android.Support.V7.Widget;
using Android.Views;
using Android.Widget;
using MvvmCross.Platform.WeakSubscription;
using MvvmCross.Binding.Droid.BindingContext;
using MvvmCross.Droid.Support.V7.Fragging.Fragments;
using MvvmCross.Droid.Support.V7.RecyclerView;
using MvvmCross.Droid.Support.V4;
using Example.Core.ViewModels;
using MvvmCross.Droid.Support.V7.Fragging.Attributes;

namespace Example.Droid.Fragments
{
    [MvxFragment(typeof(MainViewModel), Resource.Id.content_frame)]
    [Register("example.droid.fragments.RecyclerViewFragment")]
    public class RecyclerViewFragment : MvxFragment<RecyclerViewModel>
    {
        private IDisposable _itemSelectedToken;

        public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
        {
            var ignore = base.OnCreateView(inflater, container, savedInstanceState);

            var view = this.BindingInflate(Resource.Layout.fragment_recyclerview, null);

            var recyclerView = view.FindViewById<MvxRecyclerView>(Resource.Id.my_recycler_view);
            if (recyclerView != null)
            {
                recyclerView.HasFixedSize = true;
                var layoutManager = new LinearLayoutManager(Activity);
                recyclerView.SetLayoutManager(layoutManager);
            }

            _itemSelectedToken = ViewModel.WeakSubscribe(() => ViewModel.SelectedItem,
                (sender, args) => {
                    if (ViewModel.SelectedItem != null)
                        Toast.MakeText(Activity,
                            $"Selected: {ViewModel.SelectedItem.Title}",
                            ToastLength.Short).Show();
                });

            var appBar = Activity.FindViewById<AppBarLayout>(Resource.Id.appbar);
            if (appBar != null)
                appBar.OffsetChanged += (sender, args) => swipeToRefresh.Enabled = args.VerticalOffset == 0;

            return view;
        }

        public override void OnDestroyView()
        {
            base.OnDestroyView();
            _itemSelectedToken.Dispose();
            _itemSelectedToken = null;
        }
    }
}

Here is my current view, where I could select and unselect the checkbox, but I do not know how to handle this select event in order to delete the selected item.

Update:

Still, I dont get how to handle selected checkbox to enable delete operation

class ListItem
{
    public int Id { get; set; }
    public string Text { get; set; }
    private bool _isChecked;

    public bool IsChecked
    {
        get { return _isChecked; }
        set
        {
            _isChecked = value;
        }
    } 
}

 public class MyViewModel:MvxViewModel
 {

    private ObservableCollection<MyListViewModel> _myListViews;

    public ObservableCollection<MyListViewModel> MyListViews
    {
        get { return _myListViews; }
        set
        {
            _myListViews= value;
            RaisePropertyChanged(() => MyListViews);
        }
    }
    public void Init(string myId)
    {
         List<ListItem> allListItems = new List<ListItem>();
         allListItems = _myService.GetAllItems(myId);
         foreach (var myTest in allListItems)
         {
           _myListViews.Add(MyListViewModel.CreateViewModel(myTest));
         }
      }
   }

解决方案

Add IsChecked property to the ListItem class and bind it to the checkbox inside listitem_recyclerviewexample like this: local:MvxBind="Checked IsChecked"

If your class looks like this you should be able to find out which items are checked and unchecked.

class ListItem
{
    public int Id { get; set; }
    public string Text { get; set; }
    private bool _isChecked;

    public bool IsChecked
    {
        get { return _isChecked; }
        set
        {
            _isChecked = value;
        }
    } 
}

这篇关于RecyclerView复选框在Xamarin MVVMCross模式的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！

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