Blazor如何实现类似于微信的Tab切换？

是否有小伙伴在使用tab的时候想进行滑动切换Tab？

并且有滑动左出左进，右出右进的效果 ，本文将讲解怎么在Blazor中去通过滑动切换Tab

本文中的UI组件使用的是MASA Blazor,您也可以是其他的UI框架，这个并不影响实际的运行效果，本文案例是兼容PC和Android的，演示效果是android中执行的，在PC中执行效果依然有效（亲测）

首先安装MASA Blazor 根据 MASA Blazor安装MASA Blazor

准备工作

1. 创建 AppBar.razor文件

2. 修改MainLayout.razor文件代码

@inherits LayoutComponentBase

<MApp>
    <AppBar>
        <div class="body">
            @Body
        </div>
    </AppBar>
</MApp>

<style>
.body {
    /*设置内容高度 需要减去导航栏的高度*/
    height: calc(100vh - 48px);
    max-height: calc(100vh - 48px);
}
</style>

1. 创建 AppBar.razor.css 文件并且添加相关代码 ，以下代码是为了实现切换的时候有一个出入效果，具体代码案例来自Animista - On-Demand CSS Animations Library

   
   /*左边滑动出*/
   .slide-out-left {
       -webkit-animation: slide-out-left 0.5s;
       animation: slide-out-left 0.5s;
   }
   
   /*右边滑动出*/
   .slide-out-right {
       -webkit-animation: slide-out-right 0.5s;
       animation: slide-out-right 0.5s;
   }
   
   /*右边滑动进*/
   .slide-in-right {
       -webkit-animation: slide-in-right 0.5s cubic-bezier(0.250, 0.460, 0.450, 0.940) both;
       animation: slide-in-right 0.5s cubic-bezier(0.250, 0.460, 0.450, 0.940) both;
   }
   
   /*左边滑动进*/
   .slide-in-left {
       -webkit-animation: slide-in-left 0.5s;
       animation: slide-in-left 0.5s;
   }
   
   @-webkit-keyframes slide-out-left {
       0% {
           -webkit-transform: translateX(0);
           transform: translateX(0);
           opacity: 1;
       }
   
       100% {
           -webkit-transform: translateX(-1000px);
           transform: translateX(-1000px);
           opacity: 0;
       }
   }
   
   @keyframes slide-out-left {
       0% {
           -webkit-transform: translateX(0);
           transform: translateX(0);
           opacity: 1;
       }
   
       100% {
           -webkit-transform: translateX(-1000px);
           transform: translateX(-1000px);
           opacity: 0;
       }
   }
   
   @-webkit-keyframes slide-out-right {
       0% {
           -webkit-transform: translateX(0);
           transform: translateX(0);
           opacity: 1;
       }
   
       100% {
           -webkit-transform: translateX(1000px);
           transform: translateX(1000px);
           opacity: 0;
       }
   }
   
   @keyframes slide-out-right {
       0% {
           -webkit-transform: translateX(0);
           transform: translateX(0);
           opacity: 1;
       }
   
       100% {
           -webkit-transform: translateX(1000px);
           transform: translateX(1000px);
           opacity: 0;
       }
   }
   
   @-webkit-keyframes slide-in-left {
       0% {
           -webkit-transform: translateX(-1000px);
           transform: translateX(-1000px);
           opacity: 0;
       }
   
       100% {
           -webkit-transform: translateX(0);
           transform: translateX(0);
           opacity: 1;
       }
   }
   
   @keyframes slide-in-left {
       0% {
           -webkit-transform: translateX(-1000px);
           transform: translateX(-1000px);
           opacity: 0;
       }
   
       100% {
           -webkit-transform: translateX(0);
           transform: translateX(0);
           opacity: 1;
       }
   }
   @-webkit-keyframes slide-in-right {
       0% {
           -webkit-transform: translateX(1000px);
           transform: translateX(1000px);
           opacity: 0;
       }
   
       100% {
           -webkit-transform: translateX(0);
           transform: translateX(0);
           opacity: 1;
       }
   }
   
   @keyframes slide-in-right {
       0% {
           -webkit-transform: translateX(1000px);
           transform: translateX(1000px);
           opacity: 0;
       }
   
       100% {
           -webkit-transform: translateX(0);
           transform: translateX(0);
           opacity: 1;
       }
   }
   
   

2. 创建AppBar的模型用于动态添加导航栏, 创建AppBarDto.cs文件并添加相关代码

public class AppBarDto
{
    public string Key { get; set; }

    /// <summary>
    /// 标题
    /// </summary>
    public string Title { get; init; }

    /// <summary>
    /// 图标
    /// </summary>
    public string? Icon { get; set; }

    /// <summary>
    /// 路由
    /// </summary>
    public string Href { get; init; }

    public AppBarDto(string title, string href, string? icon = null)
    {
        Title = title;
        Icon = icon;
        Href = href;
        Key = Guid.NewGuid().ToString("N");
    }
}

1. 添加相关页面，在Pages文件夹下，分别创建Index.razor,Feature.razor,Friend.razor,PersonalCenter.razor

文件相关代码：

Index.razor

@page "/"
<h3>Index</h3>

Feature.razor

@page "/feature"
<h3>Feature</h3>

Friend.razor

@page "/friend"
<h3>Friend</h3>

PersonalCenter.razor

@page "/personal-center"
<h3>PersonalCenter</h3>

1. 修改AppBar.razor代码

<div class="@Class" @ontouchstart="TouchStart" @ontouchend="TouchEnd" @onmousedown="Mousedown" @onmouseup="Mouseup" style="height: 100%">
    @ChildContent
</div>

 @*这里也可以是其他组件的Tab，其实只是记录当前的导航的数据*@
<MTabs Centered
       BackgroundColor="indigo"
       ShowArrows="false"
       Value="selectModel.Key"
       Dark>
    @foreach (var i in AppBars)
    {
        <MTab Value="i.Key" OnClick="()=>GoHref(i)">
            @if (!string.IsNullOrEmpty(i.Icon))
            {
                <MIcon Dark>@i.Icon</MIcon>
            }
            @i.Title
        </MTab>
    }
</MTabs>

1. 创建AppBar.razor.cs 添加以下代码

public partial class AppBar
{
    #region Inject

    [Inject]
    public required NavigationManager NavigationManager { get; set; }

    #endregion

    private readonly List<AppBarDto> AppBars = new();

    [Parameter]
    public RenderFragment ChildContent { get; set; }

    private AppBarDto selectModel;

    private string Class { get; set; }

    protected override void OnInitialized()
    {
        AppBars.Add(new AppBarDto("首页", "/", "home"));
        AppBars.Add(new AppBarDto("好友", "/personal-center", "mdi-account-group-outline"));
        AppBars.Add(new AppBarDto("功能", "/feature", "mdi-wrench"));
        AppBars.Add(new AppBarDto("个人中心", "/personal-center", "mdi-badge-account-alert"));

        // 默认选择的导航标签
        selectModel = AppBars[0];

        base.OnInitialized();
    }

    /// <summary>
    /// 导航栏跳转
    /// </summary>
    /// <param name="appBar"></param>
    private void GoHref(AppBarDto appBar)
    {
        // 防止重复点击
        if(appBar == selectModel)
        {
            return;
        }

        // 当点击导航的索引大于现在导航时启动滑动效果
        if(AppBars.IndexOf(appBar) > AppBars.IndexOf(selectModel))
        {
            Class = "slide-out-left";
            Task.Run(async () =>
            {
                // 由于特效时间为0.5s 这里是等待特效完成
                await Task.Delay(450);
                NavigationManager.NavigateTo(selectModel.Href);
                Class = "slide-in-right";
                _ = InvokeAsync(StateHasChanged);
            });
        }
        // 当点击导航的索引小于现在导航时启动滑动效果
        else if (AppBars.IndexOf(appBar) < AppBars.IndexOf(selectModel))
        {
            Class = "slide-out-right";
            Task.Run(async () =>
            {
                // 由于特效时间为0.5s 这里是等待特效完成
                await Task.Delay(450);
                NavigationManager.NavigateTo(selectModel.Href);
                Class = "slide-in-left";
                _ = InvokeAsync(StateHasChanged);
            });
        }
        selectModel = appBar;
        NavigationManager.NavigateTo(appBar.Href);
    }

    /// <summary>
    /// 开始X坐标
    /// </summary>
    private double _startX;

    #region 移动端滑动处理

    /// <summary>
    /// 记录开始坐标
    /// </summary>
    /// <param name="args"></param>
    private void TouchStart(TouchEventArgs args)
    {
        var touch = args.ChangedTouches[0];
        _startX = touch.ScreenX;
    }

    private void TouchEnd(TouchEventArgs args)
    {
        var touch = args.ChangedTouches[0];
        Switchover((decimal)touch.ScreenX);
    }

    #endregion

    #region PC滑动处理

    /// <summary>
    /// 记录开始坐标
    /// </summary>
    /// <param name="args"></param>
    private void Mousedown(MouseEventArgs args)
    {
        _startX = args.ScreenX;
    }

    private void Mouseup(MouseEventArgs args)
    {
        Switchover((decimal)args.ScreenX);
    }

    #endregion

    private void Switchover(decimal screenX)
    {
        var index = AppBars.IndexOf(selectModel);
        // 限制过度滑动
        if (index == AppBars.Count || index > AppBars.Count)
        {
            return;
        }

        // 设置滑动最大位限制，达到这个限制才滑动生效
        var size = 200;

        // 需要滑动200才切换 如果开始坐标x大于 当前结束的x坐标往右边切换tab
        if ((decimal)_startX - size > screenX)
        {
            // 如果右边往左边滑动 当前索引是当前最大数量的话不需要切换
            if (index == AppBars.Count - 1)
            {
                return;
            }
            selectModel = AppBars[index + 1];
            Class = "slide-out-left";

            Task.Run(async () =>
            {
                // 由于特效时间为0.5s 这里是等待特效完成
                await Task.Delay(450);
                NavigationManager.NavigateTo(selectModel.Href);
                Class = "slide-in-right";
                _ = InvokeAsync(StateHasChanged);
            });
        }
        else if ((decimal)_startX + size < screenX)
        {
            // 如果左边往右边滑动 当前索引是0的话不需要切换
            if (index == 0)
            {
                return;
            }
            selectModel = AppBars[index - 1];
            Class = "slide-out-right";
            Task.Run(async () =>
            {
                // 由于特效时间为0.5s 这里是等待特效完成
                await Task.Delay(450);
                NavigationManager.NavigateTo(selectModel.Href);
                Class = "slide-in-left";
                _ = InvokeAsync(StateHasChanged);
            });
        }
    }
}

运行效果：

一个热爱学习的token

qq交流群：737776595

微信交流群：