xamarin.form 中的弹出消息框 [英] popup message box in xamarin.form

问题描述

我想做的是类似于DisplayAlert，在右上角弹出一个包含图像、内容和一个小的关闭按钮的显示页面.显示页面不应覆盖整个手机，而应覆盖手机 UI 的 80% 左右，背景仍为父页面.

我正在尝试使用 PushModalAsync 和 PopModalAsync，但是没有运气.输出不是我所期望的.

基本上，我有一个列表视图，每当从屏幕中选择项目时，它都会调用 popUpMethod:

 list.ItemSelected += MyMethod;

在 MyMethod 中，我将调用 popUpPage

async void MyMethod(object sender, SelectedItemChangedEventArgs e){内容 = 等待 PopUpPage();}

这是我的 PopUpPage 方法

私有异步任务弹出页面(){StackLayout objPopUp = new StackLayout() { HeightRequest = 100, WidthRequest= 100, VerticalOptions = LayoutOptions.CenterAndExpand};标签 lblMessage = 新标签()；lblMessage.Text = "欢迎";objPopUp.Children.Add(lblMessage);返回 objPopUp;}

我正在尝试在弹出页面中设置高度和宽度.但是，它仍然覆盖整个屏幕，这不是我想要的.如果需要任何充值信息，请告诉我，谢谢.

P/S : 我是用 xamarin.Form(portable) 设计的

解决方案

您可以在 Xamarin.Forms 中创建自定义弹出窗口来完成此操作

这是我创建的自定义 ContentView.它使用 BoxView 来呈现背景淡化的外观，并使用 Frame 为弹出窗口添加阴影.

我还使用动画使自定义弹出窗口看起来好像从屏幕上弹出一样！

示例应用

此示例应用的代码可在 Github 上获得:

代码片段

public class WelcomeView : ContentView{只读 BoxView _backgroundOverlayBoxView;只读帧_overlayFrame；只读 StackLayout _textAndButtonStack;只读相对布局 _relativeLayout;公共欢迎视图(){const string titleText = "欢迎";const string bodyText = "Enjoy InvestmentDataSampleApp";const string okButtonText = "好的，谢谢！";var whiteWith75Opacity = new Color(255, 255, 255, 0.75);_backgroundOverlayBoxView = 新的 BoxView{BackgroundColor = whiteWith75Opacity};_backgroundOverlayBoxView.Opacity = 0;_overlayFrame = 新框架{HasShadow = 真，背景颜色 = 颜色.白色};_overlayFrame.Scale = 0;var titleLabel = 新标签{FontAttributes = FontAttributes.Bold,文字 = 标题文字，Horizo​​ntalTextAlignment = TextAlignment.Center};var bodyLabel = 新标签{文字 = 正文，Horizo​​ntalTextAlignment = TextAlignment.Center};var blackWith75PercentOpacity = new Color(0, 0, 0, 0.75);var okButton = 新按钮{背景颜色 = blackWith75PercentOpacity，TextColor = Color.White，边框宽度 = 1，BorderColor = blackWith75PercentOpacity，FontAttributes = FontAttributes.Bold,边距 = 新厚度(5),文本 = okButtonText};okButton.Clicked += (sender, e) =>{Device.BeginInvokeOnMainThread(async () =>{等待 this.FadeTo(0);this.IsVisible = false;this.InputTransparent = true;});}_textAndButtonStack = 新的 StackLayout{Horizo​​ntalOptions = LayoutOptions.CenterAndExpand，间距 = 20,儿童 = {标题标签，身体标签，确定按钮}};_textAndButtonStack.Scale = 0;_relativeLayout = 新的RelativeLayout();FuncgettextAndButtonStackHeight = (p) =>_textAndButtonStack.Measure(_relativeLayout.Width, _relativeLayout.Height).Request.Height;FuncgettextAndButtonStackWidth = (p) =>_textAndButtonStack.Measure(_relativeLayout.Width, _relativeLayout.Height).Request.Width;_relativeLayout.Children.Add(_backgroundOverlayBoxView,Constraint.Constant(-10),Constraint.Constant(0),Constraint.RelativeToParent(parent => parent.Width + 20),Constraint.RelativeToParent(parent => parent.Height));_relativeLayout.Children.Add(_overlayFrame,Constraint.RelativeToParent(parent => parent.Width/2 - gettextAndButtonStackWidth(parent)/2 - 20),Constraint.RelativeToParent(parent => parent.Height/2 - gettextAndButtonStackHeight(parent)/2 - 10),Constraint.RelativeToParent(parent => gettextAndButtonStackWidth(parent) + 30),Constraint.RelativeToParent(parent => gettextAndButtonStackHeight(parent) + 30));_relativeLayout.Children.Add(_textAndButtonStack,Constraint.RelativeToView(_overlayFrame, (parent, view) => view.X + 15),Constraint.RelativeToView(_overlayFrame, (parent, view) => view.Y + 15));if (Device.OS == TargetPlatform.Android){_overlayFrame.IsVisible = false;_textAndButtonStack.BackgroundColor = whiteWith90Opacity;}内容 = _relativeLayout;}公共无效显示视图(){Device.BeginInvokeOnMainThread(async () =>{var animationList = new List{_backgroundOverlayBoxView.FadeTo(1,AnimationConstants.WelcomeViewAnimationTime),_textAndButtonStack.ScaleTo(AnimationConstants.WelcomeViewMaxSize, AnimationConstants.WelcomeViewAnimationTime),_overlayFrame.ScaleTo(AnimationConstants.WelcomeViewMaxSize,AnimationConstants.WelcomeViewAnimationTime)};等待 Task.WhenAll(animationList);动画列表 = 新列表<任务>{_textAndButtonStack.ScaleTo(AnimationConstants.WelcomeViewNormalSize, AnimationConstants.WelcomeViewAnimationTime),_overlayFrame.ScaleTo(AnimationConstants.WelcomeViewNormalSize, AnimationConstants.WelcomeViewAnimationTime)};等待 Task.WhenAll(animationList);});}}

What I am trying to do is similar to DisplayAlert, popup a display page that contains image, content and a small close button at top right. The display page shouldn't cover the whole phone but just around 80% of the phone UI, background remain as parent page.

I am trying to play around with PushModalAsync and PopModalAsync, however with no luck. The output is not what I expected.

Basically, I have a listview, whenever item is selected from screen it will call for popUpMethod:

 list.ItemSelected += MyMethod;

inside MyMethod i will call popUpPage

async void MyMethod(object sender, SelectedItemChangedEventArgs e){
Content = await PopUpPage();
}

and this is my PopUpPage method

private async Task<StackLayout> PopUpPage()
{
     StackLayout objPopUp = new StackLayout() { HeightRequest = 100, WidthRequest= 100, VerticalOptions = LayoutOptions.CenterAndExpand};

     Label lblMessage = new Label();
     lblMessage.Text = "Welcome";

     objPopUp.Children.Add(lblMessage);

     return objPopUp;
}

I am trying to set the height and width inside my popup page. However, it is still covering the whole screen which is not what I want. let me know if any top up information is needed, thank you.

P/S : i designed it in xamarin.Form(portable)

解决方案

You can create a custom pop-up to accomplish this in Xamarin.Forms

Here is a custom ContentView that I created. It uses a BoxView to give the appearance of fading the background, and uses a Frame to add a shadow to the pop-up.

I also use animations to make the custom pop-up appear as if it is springing off of the screen!

Sample App

The code for this sample app is available on Github:

https://github.com/brminnick/InvestmentDataSampleApp

Code Snippet

public class WelcomeView : ContentView
{
    readonly BoxView _backgroundOverlayBoxView;
    readonly Frame _overlayFrame;
    readonly StackLayout _textAndButtonStack;

    readonly RelativeLayout _relativeLayout;

    public WelcomeView()
    {
        const string titleText = "Welcome";
        const string bodyText = "Enjoy InvestmentDataSampleApp";
        const string okButtonText = "Ok, thanks!";

        var whiteWith75Opacity = new Color(255, 255, 255, 0.75);
        _backgroundOverlayBoxView = new BoxView
        {
            BackgroundColor = whiteWith75Opacity
        };
        _backgroundOverlayBoxView.Opacity = 0;

        _overlayFrame = new Frame
        {
            HasShadow = true,
            BackgroundColor = Color.White
        };
        _overlayFrame.Scale = 0;

        var titleLabel = new Label
        {
            FontAttributes = FontAttributes.Bold,
            Text = titleText,
            HorizontalTextAlignment = TextAlignment.Center
        };

        var bodyLabel = new Label
        {
            Text = bodyText,
            HorizontalTextAlignment = TextAlignment.Center
        };

        var blackWith75PercentOpacity = new Color(0, 0, 0, 0.75);
        var okButton = new Button
        {
            BackgroundColor = blackWith75PercentOpacity,
            TextColor = Color.White,
            BorderWidth = 1,
            BorderColor = blackWith75PercentOpacity,
            FontAttributes = FontAttributes.Bold,
            Margin = new Thickness(5),
            Text = okButtonText
        };
        okButton.Clicked += (sender, e) => 
        {
            Device.BeginInvokeOnMainThread(async () =>
            {
                await this.FadeTo(0);
                this.IsVisible = false;
                this.InputTransparent = true;
            });
        }

        _textAndButtonStack = new StackLayout
        {
            HorizontalOptions = LayoutOptions.CenterAndExpand,
            Spacing = 20,
            Children = {
                titleLabel,
                bodyLabel,
                okButton
            }
        };
        _textAndButtonStack.Scale = 0;

        _relativeLayout = new RelativeLayout();
        Func<RelativeLayout, double> gettextAndButtonStackHeight = (p) => _textAndButtonStack.Measure(_relativeLayout.Width, _relativeLayout.Height).Request.Height;
        Func<RelativeLayout, double> gettextAndButtonStackWidth = (p) => _textAndButtonStack.Measure(_relativeLayout.Width, _relativeLayout.Height).Request.Width;


        _relativeLayout.Children.Add(_backgroundOverlayBoxView,
            Constraint.Constant(-10),
            Constraint.Constant(0),
            Constraint.RelativeToParent(parent => parent.Width + 20),
            Constraint.RelativeToParent(parent => parent.Height)
        );
        _relativeLayout.Children.Add(_overlayFrame,
            Constraint.RelativeToParent(parent => parent.Width / 2 - gettextAndButtonStackWidth(parent) / 2 - 20),
            Constraint.RelativeToParent(parent => parent.Height / 2 - gettextAndButtonStackHeight(parent) / 2 - 10),
            Constraint.RelativeToParent(parent => gettextAndButtonStackWidth(parent) + 30),
            Constraint.RelativeToParent(parent => gettextAndButtonStackHeight(parent) + 30)
        );

        _relativeLayout.Children.Add(_textAndButtonStack,
             Constraint.RelativeToView(_overlayFrame, (parent, view) => view.X + 15),
             Constraint.RelativeToView(_overlayFrame, (parent, view) => view.Y + 15)
        );

        if (Device.OS == TargetPlatform.Android)
        {
            _overlayFrame.IsVisible = false;
            _textAndButtonStack.BackgroundColor = whiteWith90Opacity;
        }

        Content = _relativeLayout;
    }

    public void DisplayView()
    {
        Device.BeginInvokeOnMainThread(async () =>
        {
            var animationList = new List<Task>
            {
                _backgroundOverlayBoxView.FadeTo(1,AnimationConstants.WelcomeViewAnimationTime),
                _textAndButtonStack.ScaleTo(AnimationConstants.WelcomeViewMaxSize, AnimationConstants.WelcomeViewAnimationTime),
                _overlayFrame.ScaleTo(AnimationConstants.WelcomeViewMaxSize,AnimationConstants.WelcomeViewAnimationTime)
            };
            await Task.WhenAll(animationList);

            animationList = new List<Task>
            {
                _textAndButtonStack.ScaleTo(AnimationConstants.WelcomeViewNormalSize, AnimationConstants.WelcomeViewAnimationTime),
                _overlayFrame.ScaleTo(AnimationConstants.WelcomeViewNormalSize, AnimationConstants.WelcomeViewAnimationTime)
            };
            await Task.WhenAll(animationList);
        });
    }
}

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