Xamarin 表单在 TabbedPage 中添加按钮 [英] Xamarin forms Add button in TabbedPage
问题描述
我有一个问题.我创建了以下 TabbedPage:
I have a question. I created the following TabbedPage:
<?xml version="1.0" encoding="utf-8" ?>
<TabbedPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:d="http://xamarin.com/schemas/2014/forms/design"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:views="clr-namespace:MyApp.Views"
mc:Ignorable="d"
x:Class="MyApp.Views.MainPage"
xmlns:android="clr-namespace:Xamarin.Forms.PlatformConfiguration.AndroidSpecific;assembly=Xamarin.Forms.Core"
android:TabbedPage.ToolbarPlacement="Bottom"
BarBackgroundColor="White"
BarTextColor="Black"
android:TabbedPage.BarItemColor="#B2B2B2"
android:TabbedPage.BarSelectedItemColor="#56D7A5"
android:TabbedPage.IsSwipePagingEnabled="False">
<TabbedPage.Children>
<NavigationPage Title="page1" IconImageSource="navbar_page1">
<x:Arguments>
<views:page1 NavigationPage.HasNavigationBar="False" />
</x:Arguments>
</NavigationPage>
<NavigationPage Title="page2" IconImageSource="navbar_page2">
<x:Arguments>
<views:page2 NavigationPage.HasNavigationBar="False" />
</x:Arguments>
</NavigationPage>
<NavigationPage Title="page3" IconImageSource="navbar_page3">
<x:Arguments>
<views:page3 NavigationPage.HasNavigationBar="False" />
</x:Arguments>
</NavigationPage>
</TabbedPage>
现在在每个页面上我都添加了这个自定义 FabMenu，如下所示:
Now on every page I have added this custom FabMenu like this:
<c:FloatingMenu Margin="0, 0, 10, 10" BGColor="#56D7A5" OpenIcon="openFab_icon" CloseIcon="closeFab_icon"
AbsoluteLayout.LayoutBounds=".95,.95" AbsoluteLayout.LayoutFlags="PositionProportional">
<c:FloatingButton x:Name="btnAddHomework" BGColor="#59E1FF" IconSrc="add_homework_icon" OnClickCommand="{Binding btnAddHomeworkCommand}" />
<c:FloatingButton x:Name="btnAddDeadline" BGColor="#0FF1A0" IconSrc="add_deadline_icon"/>
<c:FloatingButton x:Name="btnAddTest" BGColor="#5988FF" IconSrc="add_test_icon"/>
</c:FloatingMenu>
问题是每个页面都有自己的 FabMenu，所以你会看到它在每个页面上消失并重新出现，所以我的问题是:是否有某种根视图覆盖了 TabbedPage 中的所有选项卡?
The problem is that every page has his own FabMenu, so you see it dissapear and reappear on every page, so my question is: Is there some kind of root view that overlays all the tabs in the TabbedPage?
请告诉我我是如何做到的！
Please let me know how I do that!
推荐答案
免责声明
我想出了一种仅使用纯 Xamarin.Forms 即可创建所需效果的方法.继续阅读并注意解决方案的棘手部分.
该解决方案是通过实施AbsoluteLayout、CarouselView、IndicatorView 和DataTemplateSelector 实现的.Xamarin.Forms 4.8 应该在下面.如果使用较低版本，请考虑CarouselView 或IndicatorView 等功能可能处于预览 状态.
This solution is achieved implementing AbsoluteLayout, CarouselView, IndicatorView and DataTemplateSelector. Xamarin.Forms 4.8 is supposed in what follows. If a lower version is used, please take into account that features like CarouselView or IndicatorView could be in Preview status.
DataTemplateSelector、CarouselView 和 IndicatorView 用于模拟 TabbedPage 和 AbsoluteLayout 用于提供Overlay.
DataTemplateSelector, CarouselView and IndicatorView are used to simulate a TabbedPage, and AbsoluteLayout is used to provide the Overlay.
那么，现在有了解决方案:
So, now with the solution:
在这里，您可以为您想要的每个页面创建一个视图.在这个例子中，我希望我的应用程序包含两个页面，所以我创建了两个视图(隐藏的代码保持不变):
Here you create a view for each of the pages you want. In this example i want my application to consist of two pages, so i create two views (code behind remains untouched):
View1.xaml
<ContentView xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="overlayTest.View1"
BackgroundColor="Black">
<ContentView.Content>
<StackLayout>
<Label Text="Welcome to Xamarin.Forms 1!"
TextColor="White"
VerticalOptions="CenterAndExpand"
HorizontalOptions="CenterAndExpand" />
</StackLayout>
</ContentView.Content>
</ContentView>
View2.xaml
<?xml version="1.0" encoding="UTF-8"?>
<ContentView xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="overlayTest.View2">
<ContentView.Content>
<StackLayout>
<Label Text="Welcome to Xamarin.Forms 2!"
VerticalOptions="CenterAndExpand"
HorizontalOptions="CenterAndExpand" />
</StackLayout>
</ContentView.Content>
</ContentView>
创建一个DataTemplateSelector
这将被 CarouselView 用来根据当前的 Position 选择一个视图或另一个视图.
Create a DataTemplateSelector
This will be used by the CarouselView in order to select one view or the other depending on the current Position.
using System;
using Xamarin.Forms;
namespace overlayTest
{
class MyTemplateSelector : DataTemplateSelector
{
readonly DataTemplate view1, view2;
public MyTemplateSelector()
{
view1 = new DataTemplate(typeof(View1));
view2 = new DataTemplate(typeof(View2));
}
protected override DataTemplate OnSelectTemplate(object item, BindableObject container)
{
String s = item.ToString();
if(s == "1")
{
return view1;
}
return view2;
}
}
}
创建您的主页
Page1.xaml
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:t="clr-namespace:overlayTest"
x:Class="overlayTest.Page1">
<ContentPage.Resources>
<ResourceDictionary>
<t:MyTemplateSelector x:Key="templateSelector"/>
</ResourceDictionary>
</ContentPage.Resources>
<ContentPage.Content>
<AbsoluteLayout>
<StackLayout AbsoluteLayout.LayoutBounds="0,0,1,1"
AbsoluteLayout.LayoutFlags="All"
Padding="0"
Spacing="0">
<CarouselView ItemTemplate="{StaticResource templateSelector}"
IndicatorView="indicatorView">
<CarouselView.ItemsSource>
<x:Array Type="{x:Type x:String}">
<x:String>1</x:String>
<x:String>2</x:String>
</x:Array>
</CarouselView.ItemsSource>
</CarouselView>
<IndicatorView x:Name="indicatorView">
<IndicatorView.IndicatorTemplate>
<DataTemplate>
<StackLayout HorizontalOptions="FillAndExpand">
<Frame Margin="10">
<Label/>
</Frame>
</StackLayout>
</DataTemplate>
</IndicatorView.IndicatorTemplate>
</IndicatorView>
</StackLayout>
<ContentView
IsVisible="True" VerticalOptions="Start"
AbsoluteLayout.LayoutBounds="0,0,1,1"
AbsoluteLayout.LayoutFlags="All"
BackgroundColor="Transparent">
<Frame CornerRadius="10"
Margin="20"
VerticalOptions="StartAndExpand"
HorizontalOptions="CenterAndExpand" InputTransparent="False">
<StackLayout Padding="0">
<Label
FontSize="Medium"
TextColor="Black"/>
<StackLayout Orientation="Horizontal"
HorizontalOptions="CenterAndExpand">
<Label Text="I am floating here"/>
<Switch IsToggled="True" />
</StackLayout>
<Button Text="Save"
BackgroundColor="Accent"/>
</StackLayout>
</Frame>
</ContentView>
</AbsoluteLayout>
</ContentPage.Content>
</ContentPage>
在后面的代码中，我们设置了选项卡的名称.在这里请注意我假设 StackLayout 的元素树 ->框架 ->标签.如果你改变了IndicatorTemplate，你也必须修改这部分代码！
And in the code behind we set the name of the tabs. Here please put attention in the fact that i am supposing an element tree of a StackLayout -> Frame -> Label. If you change the IndicatorTemplate, you will have to also modify this part of the code!
Page1.xaml.cs
using System.Linq;
using Xamarin.Forms;
using Xamarin.Forms.Xaml;
namespace overlayTest
{
[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class Page1 : ContentPage
{
public Page1()
{
InitializeComponent();
indicatorView.PropertyChanged += (s, a) =>
{
if (a.PropertyName == IndicatorView.HeightProperty.PropertyName)
{
var indicators = indicatorView.IndicatorLayout.Children.ToList();
int counter = 0;
foreach(var indicator in indicators)
{
var indicatorBaseStack = (StackLayout)indicator;
var indicatorFrame = (Frame)indicatorBaseStack.Children[0];
var indicatorFrameLabel = (Label)indicatorFrame.Content;
indicatorFrameLabel.Text = counter == 0 ? "View1" : "View2";
counter++;
}
}
};
}
}
}
最后将该页面设置为 App 的 MainPage 属性:
public App()
{
InitializeComponent();
MainPage = new Page1();
}
最终结果如下:
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