Question

所以，我正在开发一个Xamarin项目。我正在开发一个应用程序，它将应用程序中有用的弹出窗口发送给用户（例如提示）。用户可以设置他们在应用程序中接收此弹出窗口的时间（例如，他们可以在19:00或12:00接收弹出窗口）。我为这个名为Alert的人创建了一个自定义类。应用程序的IOS版本正在按预期工作

然而，由于股票Android警报没有任何方法可以在其中添加输入字段，我必须为此警报创建一个特殊视图。我现在遇到的主要问题是来自自定义视图的用户输入未发送到Xamarin表单警报。

Android代码：

public class Alert : IAlert
{
    public static readonly int AlertWidth = Device.Idiom == TargetIdiom.Phone ? 270 : 320;

    class AlertDialogFragment : DialogFragment
    {
        public string Title;
        public string Body;
        public View Content;
        public List<AlertButton> Buttons;
        public Func<Task> tcs;


        public Dialog AndroidCustomAlert(Activity activ)
        {
            Android.Views.LayoutInflater inflater = Android.Views.LayoutInflater.From(activ);
            Android.Views.View view = inflater.Inflate(Resource.Layout.AlertDialogLayout, null);

            AlertDialog.Builder builder = new AlertDialog.Builder(activ);
            builder.SetView(view);
            Android.Widget.TextView title = view.FindViewById<Android.Widget.TextView>(Resource.Id.Login);
            title.Text = Title;

            Android.Widget.TextView body = view.FindViewById<Android.Widget.TextView>(Resource.Id.pincodeText);
            body.Text = Body;

            Android.Widget.Timepicker timepicker= view.FindViewById<Android.Widget.Timepicker >(Resource.Id.timepicker);
            Android.Widget.Button btnPositive = view.FindViewById<Android.Widget.Button>(Resource.Id.btnLoginLL);
            Android.Widget.Button btnNegative = view.FindViewById<Android.Widget.Button>(Resource.Id.btnClearLL);
            Android.Widget.Button btnNeutral = view.FindViewById<Android.Widget.Button>(Resource.Id.btnNeutral);


            //Checks if there are no buttons, and if there aren't any, creates a neutral one
            if (Buttons == null || Buttons.Count == 0)
            {
                btnPositive.Visibility = Android.Views.ViewStates.Gone;
                btnNegative.Visibility = Android.Views.ViewStates.Gone;
                btnNeutral.Visibility = Android.Views.ViewStates.Visible;
                timepicker.Visibility = Android.Views.ViewStates.Gone;

                Buttons = new List<AlertButton> {
                new AlertButton {
                    Text = "Oké",
                    IsPreferred = true,
                    Action = () => false
                }
            };
                btnNeutral.Text = Buttons.First().Text;
                btnNeutral.Click += delegate
                {
                    CommandsForButtons(Buttons.First());
                };
            }


            //Positive button feedback
            btnPositive.Text = Buttons.Last().Text;
            btnPositive.Click += delegate
            {
                CommandsForButtons(Buttons.Last());
            };

            //Negative button feedback
            btnNegative.Text = Buttons.First().Text;
            btnNegative.Click += delegate
            {
                CommandsForButtons(Buttons.First());
            };

            builder.SetCancelable(false);
            return builder.Create();
        }

        public void CommandsForButtons(AlertButton button)
        {
            var command = new Command(async () =>
            {
                var ab = button;
                var cont = true;
                if (ab.Action != null)
                    cont = ab.Action();
                if (ab.ActionAsync != null)
                {
                    cont = cont && await ab.ActionAsync();
                }
                if (!cont)
                {
                    Dismiss();
                }
            });

            command.Execute(this);
        }

        public override Dialog OnCreateDialog(Bundle savedInstanceState)
        {
            var test = AndroidCustomAlert(Activity);
            //test.SetCanceledOnTouchOutside(false);
            return test;
        }

    }

    public async Task Show(string title, string body, View content, List<AlertButton> buttons)
    {

        var tcs = new TaskCompletionSource<object>();

        var adf = new AlertDialogFragment
        {
            Title = title,
            Body = body,
            Content = content,
            Buttons = buttons
        };
        var FragmentManager = ((Activity)Forms.Context).FragmentManager;

        FragmentTransaction ft = FragmentManager.BeginTransaction();
        //Remove fragment else it will crash as it is already added to backstack
        Fragment prev = FragmentManager.FindFragmentByTag("alert");
        if (prev != null)
        {
            ft.Remove(prev);
        }

        ft.AddToBackStack(null);

        adf.Show(ft, "alert");

        //await tcs.Task;

        return;
    }

}

警报类：

public interface IAlert
{
    Task Show(string title, string body, View content, List<AlertButton> buttons);
}

public static class Alert
{
    public static async Task Show(string title, string body, View content = null, params AlertButton[] buttons)
    {
        var enabled = MainApp.BackEnabled;
        MainApp.BackEnabled = false;
        await DependencyService.Get<IAlert>().Show(title, body, content, buttons.ToList());
        MainApp.BackEnabled = enabled;
    }
}

public class AlertButton 
{
    public string Text { get; set; }
    public bool IsDestructive { get; set; }
    public bool IsPreferred { get; set; }
    public Func<bool> Action { get; set; }
    public Func<Task<bool>> ActionAsync { get; set; }

}}

IOS代码：

public class iOSAlert : IAlert
{
    public static readonly int AlertWidth = Device.Idiom == TargetIdiom.Phone ? 270 : 320;

    public async Task Show(string title, string body, View content, List<AlertButton> buttons)
    {
        if (buttons == null || buttons.Count == 0)
        {
            buttons = new List<AlertButton> {
                new AlertButton {
                    Text = "Oké",
                    IsPreferred = true,
                    Action = () => false
                }
            };
        }

        Func<Task> dismiss = null;

        var captionSize = (double)StyleKit.PhoneDarkLabelStyles.Caption.Setters.First(s => s.Property == Label.FontSizeProperty).Value;
        var titleSize = (double)StyleKit.PhoneDarkLabelStyles.Title.Setters.First(s => s.Property == Label.FontSizeProperty).Value;

        var top = new StackLayout {
            Padding = new Thickness(15, 20, 15, 20),
            Spacing = 3,
            Children = {
                new Label {
                    Text = title,
                    Style = StyleKit.PhoneDarkLabelStyles.Title,
                    FontSize = Math.Max(16, titleSize),
                    HorizontalTextAlignment = TextAlignment.Center
                },
                new Label {
                    Text = body,
                    Style = StyleKit.PhoneDarkLabelStyles.Body,
                    //FontSize = ,
                    FontSize = Math.Max(14, captionSize),
                    HorizontalTextAlignment = TextAlignment.Center
                } ,
                new ContentView {
                    Padding = new Thickness(0,5,0,-10),
                    VerticalOptions = LayoutOptions.EndAndExpand,
                    Content = content
                } 
            }
        };

        var buttonViews = buttons.Select(ab => new Button {
            FontSize = Math.Max(16, titleSize),
            Text = ab.Text,
            FontAttributes = ab.IsPreferred ? FontAttributes.Bold : FontAttributes.None,
            TextColor = ab.IsDestructive ? Color.Red : Color.Default,
            Command = new Command(async () => {
                var cont = true;
                if (ab.Action != null)
                    cont = ab.Action();
                if (ab.ActionAsync != null)
                    cont = cont && await ab.ActionAsync();
                if (!cont)
                    await dismiss();
            })
        }).ToList();

        var grid = new Grid {
            RowDefinitions = {
                new RowDefinition { Height = GridLength.Auto },
                new RowDefinition { Height = GridLength.Auto }
            },
            ColumnSpacing = 0,
            RowSpacing = 0
        };
        buttons.ForEach(button => {
            grid.ColumnDefinitions.Add(
                new ColumnDefinition {
                    Width = AlertWidth / buttonViews.Count
                }
            );
        });

        for (int i = 0; i < buttonViews.Count; i++)
        {
            grid.Children.Add(new BorderView {
                BorderColor = Color.FromRgba(0,0,0,0.2),
                Thickness = new Thickness(0, 1, (i + 1 < buttonViews.Count) ? 1 : 0, 0)
            }, i, 1);
            grid.Children.Add(buttonViews[i], i, 1);
        }
        grid.Children.Add(top, 0, buttons.Count, 0, 1);

        var box = new Frame {
            WidthRequest = AlertWidth,
            BackgroundColor = Color.FromRgba(1,1,1,0.96),
            Padding = 0,
            Content = grid
        };
        var outer = new AbsoluteLayout {
            BackgroundColor = Color.FromRgba(0,0,0,0.65),
            Opacity = 0,
            Children = { box }
        };
        AbsoluteLayout.SetLayoutFlags(box, AbsoluteLayoutFlags.PositionProportional);
        AbsoluteLayout.SetLayoutBounds(box,
            new Rectangle(0.5, 0.5, AbsoluteLayout.AutoSize, AbsoluteLayout.AutoSize));

        var page = new ContentPage {
            Content = /* new ScrollView { Content = */ outer // }
        };

        var tcs = new TaskCompletionSource<object>();
        var topVC = UIApplication.SharedApplication.KeyWindow.RootViewController;
        while (topVC.PresentedViewController != null) {
            topVC = topVC.PresentedViewController;
        }

        var vc = page.CreateViewController();
        topVC.Add(vc.View);
        var innerView = vc.View.Subviews[0].Subviews[0];
        vc.View.RemoveFromSuperview();

        dismiss = async () => {
            dismiss = async () => {};
            await outer.FadeTo(0, 50);
            innerView.RemoveFromSuperview();
            tcs.SetResult(null);
        };

        topVC.Add(innerView);
        await outer.FadeTo(1, 100);
        await tcs.Task;
    }
}

带条目的警报示例：

await Alert.Show(
            "Time" + (isEdit ? "Edit" : "toevoegen"),
            "Fill the time in you want to receive an notification.",
            tp,
            cancelButton,
            new AlertButton
            {
                Text = "Save",
                IsPreferred = true,
                Action = () =>
                {
                    var newTime = tp.Time.MinutesOnly();
                    if (!isEdit || newTime != time)
                    {
                        if (isEdit) scheduler.RemoveTime(time);
                        scheduler.AddTime(newTime);
                    }
                    return false;
                }
            }
        );

我有以下问题：如何将用户信息发送到Xamarin Forms警报，而不更改警报类？

亲切的问候，

弗雷德里克

Answer 1

从您的代码中，您可以使用任务显示（字符串标题，字符串正文，查看内容，列表按钮）; 要获得结果，在Android项目中，您可以使用TaskCompletionSource来等待用户输入。 https://msdn.microsoft.com/en-us/library/dd449174(v=vs.110).aspx

否则，您可以使用acr.userdialogs.prompt执行相同的操作。 https://github.com/aritchie/userdialogs/blob/master/docs/prompt.md

将用户输入从android警报发送到自定义警报xamarin

1 个答案: