Xamarin Forms的Toast等效物-Java 学习之路

是否有任何方法使用Xamarin Forms（不是Android或iOS特定的）来弹出，就像Android与Toast一样，不需要用户交互，并在（短）时间后消失？

从搜索所有我看到的是需要用户点击消失的警报 .

7 回答

这是我用来在Xamarin.iOS中显示吐司的代码片段

public void ShowToast(String message, UIView view)
    {
        UIView residualView = view.ViewWithTag(1989);
        if (residualView != null)
            residualView.RemoveFromSuperview();

        var viewBack = new UIView(new CoreGraphics.CGRect(83, 0, 300, 100));
        viewBack.BackgroundColor = UIColor.Black;
        viewBack.Tag = 1989;
        UILabel lblMsg = new UILabel(new CoreGraphics.CGRect(0, 20, 300, 60));
        lblMsg.Lines = 2;
        lblMsg.Text = message;
        lblMsg.TextColor = UIColor.White;
        lblMsg.TextAlignment = UITextAlignment.Center;
        viewBack.Center = view.Center;
        viewBack.AddSubview(lblMsg);
        view.AddSubview(viewBack);
        roundtheCorner(viewBack);
        UIView.BeginAnimations("Toast");
        UIView.SetAnimationDuration(3.0f);
        viewBack.Alpha = 0.0f;
        UIView.CommitAnimations();
    }

回复于 2024-04-20T00:49:31+08:00

3
我们'd normally use Egors Toasts plugin, but as it requires permissions on iOS for a current project we'使用Rg.Plugins.Popup nuget（https://github.com/rotorgames/Rg.Plugins.Popup）走了一条不同的路线 .

我写了一个类型为PopupPage的基本xaml / cs页面，
```
<?xml version="1.0" encoding="utf-8" ?>
<popup:PopupPage xmlns="http://xamarin.com/schemas/2014/forms"
         xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
         xmlns:popup="clr-namespace:Rg.Plugins.Popup.Pages;assembly=Rg.Plugins.Popup"
         x:Class="YourApp.Controls.ToastPage">
...
```
并让它由服务创建，您在app开始注册的接口或使用Xamarin.Forms.DependencyService来获取服务也是可行的 .

PopupPage派生页面上的服务新闻，并且确实如此
```
await PopupNavigation.PushAsync(newToastPage);
await Task.Delay(2000);
await PopupNavigation.PopAllAsync();
```
用户可以通过点击页面显示外部来取消弹出页面（假设它没有填满屏幕） .

这似乎在iOS / Droid上工作愉快，但如果有人知道这是一种冒险的方法，我愿意纠正 .
回复于 2024-04-20T00:49:31+08:00

@MengTim，为了修复@ alex-chengalan解决方案中的多个Toast问题，我只是在ShowAlert（）中包装所有内容，检查alert和alertDelay是否为null，然后在DismissMessage中，取消alert和alertDelay .

void ShowAlert(string message, double seconds)
    {
        if(alert == null && alertDelay == null) {
            alertDelay = NSTimer.CreateScheduledTimer(seconds, (obj) =>
            {
                DismissMessage();
            });
            alert = UIAlertController.Create(null, message, UIAlertControllerStyle.Alert);
            UIApplication.SharedApplication.KeyWindow.RootViewController.PresentViewController(alert, true, null);
        }
    }

    void DismissMessage()
    {
        if (alert != null)
        {
            alert.DismissViewController(true, null);
            alert = null;
        }
        if (alertDelay != null)
        {
            alertDelay.Dispose();
            alertDelay = null;
        }
    }

如果您正在寻找快速解决方案，那似乎至少可以清除UI挂起 . 我试图在导航到新页面时显示吐司，并且相信正在设置的PresentViewController基本上取消了我的导航 . 对不起，我没有在帖子内发表评论，我的名声太低了:(

回复于 2024-04-20T00:49:31+08:00

78

Forms中没有内置机制，但是这个nuget包提供了类似的东西

https://github.com/EgorBo/Toasts.Forms.Plugin

注意：这些不是问题中所要求的Android风格的祝酒词，而是UWP样式的祝酒词，它们是系统范围的通知 .

回复于 2024-04-20T00:49:31+08:00

这里's a version of Alex Chengalan'的iOS code避免了在显示多条消息时UI粘滞...

public class MessageIOS : IMessage
    {
        const double LONG_DELAY = 3.5;
        const double SHORT_DELAY = 0.75;

        public void LongAlert(string message)
        {
            ShowAlert(message, LONG_DELAY);
        }

        public void ShortAlert(string message)
        {
            ShowAlert(message, SHORT_DELAY);
        }

        void ShowAlert(string message, double seconds)
        {
            var alert = UIAlertController.Create(null, message, UIAlertControllerStyle.Alert);

            var alertDelay = NSTimer.CreateScheduledTimer(seconds, obj =>
            {
                DismissMessage(alert, obj);
            });

            UIApplication.SharedApplication.KeyWindow.RootViewController.PresentViewController(alert, true, null);
        }

        void DismissMessage(UIAlertController alert, NSTimer alertDelay)
        {
            if (alert != null)
            {
                alert.DismissViewController(true, null);
            }

            if (alertDelay != null)
            {
                alertDelay.Dispose();
            }
        }
    }

回复于 2024-04-20T00:49:31+08:00

除了Alex的回答，这里是UWP变体：

public class Message : IMessage {
  private const double LONG_DELAY = 3.5;
  private const double SHORT_DELAY = 2.0;

  public void LongAlert(string message) =>
    ShowMessage(message, LONG_DELAY);

  public void ShortAlert(string message) =>
    ShowMessage(message, SHORT_DELAY);

  private void ShowMessage(string message, double duration) {
    var label = new TextBlock {
      Text = message,
      Foreground = new SolidColorBrush(Windows.UI.Colors.White),
      HorizontalAlignment = HorizontalAlignment.Center,
      VerticalAlignment = VerticalAlignment.Center,
    };
    var style = new Style { TargetType = typeof(FlyoutPresenter) };
    style.Setters.Add(new Setter(Control.BackgroundProperty, new SolidColorBrush(Windows.UI.Colors.Black)));
    style.Setters.Add(new Setter(FrameworkElement.MaxHeightProperty, 1));
    var flyout = new Flyout {
      Content = label,
      Placement = FlyoutPlacementMode.Full,
      FlyoutPresenterStyle = style,
    };

    flyout.ShowAt(Window.Current.Content as FrameworkElement);

    var timer = new DispatcherTimer { Interval = TimeSpan.FromSeconds(duration) };
    timer.Tick += (sender, e) => {
      timer.Stop();
      flyout.Hide();
    };
    timer.Start();
  }
}

着色和造型取决于您， MaxHeight 实际上需要将高度保持在最低限度 .

回复于 2024-04-20T00:49:31+08:00

有一个简单的解决方案 . 通过使用DependencyService，您可以轻松地在Android和iOS中获得Toast-Like方法 .

Create an interface in your common package.

public interface IMessage
{
    void LongAlert(string message);
    void ShortAlert(string message);
}

Android section

[assembly: Xamarin.Forms.Dependency(typeof(MessageAndroid))]
namespace Your.Namespace
{
    public class MessageAndroid : IMessage
    {
        public void LongAlert(string message)
        {
            Toast.MakeText(Application.Context, message, ToastLength.Long).Show();
        }

        public void ShortAlert(string message)
        {
            Toast.MakeText(Application.Context, message, ToastLength.Short).Show();
        }
    }
}

iOS section

在iOs中没有像Toast这样的原生解决方案，所以我们需要实现自己的方法 .

[assembly: Xamarin.Forms.Dependency(typeof(MessageIOS))]
namespace Bahwan.iOS
{
    public class MessageIOS : IMessage
    {
        const double LONG_DELAY = 3.5;
        const double SHORT_DELAY = 2.0;

        NSTimer alertDelay;
        UIAlertController alert;

        public void LongAlert(string message)
        {
            ShowAlert(message, LONG_DELAY);
        }
        public void ShortAlert(string message)
        {
            ShowAlert(message, SHORT_DELAY);
        }

        void ShowAlert(string message, double seconds)
        {
            alertDelay = NSTimer.CreateScheduledTimer(seconds, (obj) =>
            {
                dismissMessage();
            });
            alert = UIAlertController.Create(null, message, UIAlertControllerStyle.Alert);
            UIApplication.SharedApplication.KeyWindow.RootViewController.PresentViewController(alert, true, null);
        }

        void dismissMessage()
        {
            if (alert != null)
            {
                alert.DismissViewController(true, null);
            }
            if (alertDelay != null)
            {
                alertDelay.Dispose();
            }
        }
    }
}

请注意，在每个平台中，我们必须使用DependencyService注册我们的类 .

现在，您可以在我们项目的任何位置访问Toast服务 .

DependencyService.Get<IMessage>().ShortAlert(string message); 
DependencyService.Get<IMessage>().LongAlert(string message);

回复于 2024-04-20T00:49:31+08:00

Xamarin Forms的Toast等效物

7 回答

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