StackLayout

堆栈式地放置内容
可以在xaml中完成视图，也可以在cs代码中完成视图

Xamarin的所有视图和布局都是可以
1.在xaml中完成
2.在cs代码中完成视图
（类比WPF）

示例

在cs代码中完成视图

var red = new Label
{
    Text = "Stop",
    BackgroundColor = Color.Red,
    FontSize = 20
};
var yellow = new Label
{
    Text = "Slow down",
    BackgroundColor = Color.Yellow,
    FontSize = 20
};
var green = new Label
{
    Text = "Go",
    BackgroundColor = Color.Green,
    FontSize = 20
};

//内容
Content = new StackLayout
{
    //间距
    Spacing = 10,
    Children = { red, yellow, green }
};

在xaml中完成视图

这里注意默认生成的是Page,不是ContentPage，要手动修改，不然无效

<ContentPage 
    x:Class="XamarinDemo.DemoPages.StackLayoutExample"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:XamarinDemo.DemoPages"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d" Padding="20">
    <StackLayout Spacing="10">
        <Label Text="Stop" BackgroundColor="Red" Font="20"/>
        <Label Text="Slow down" BackgroundColor="Yellow" Font="20" />
        <Label Text="Go" BackgroundColor="Green" Font="20" />
    </StackLayout>
</ContentPage>

效果

1

指定方向

Orientation:摆放方向

//垂直（从上到下）
Vertical = 0,
//水平（从左往右）
Horizontal = 1

VerticalOptions:垂直（上下）方向的选项
HorizontalOptions:水平（左右）方向的选项

Start
Center
End
Fill
StartAndExpand
CenterAndExpand
EndAndExpand
FillAndExpand

设置方向示例

//内容
Content = new StackLayout
{
    //间距
    Spacing = 10,
    //垂直方向上，从底部出发
    VerticalOptions = LayoutOptions.End,
    //堆放三个Label的方向是水平
    Orientation = StackOrientation.Horizontal,
    //水平方向上，从开始（左边）出发
    HorizontalOptions = LayoutOptions.Start,
    Children = { red, yellow, green }
};

效果

2

示例代码

https://github.com/zLulus/NotePractice/tree/dev3/Xamarin.Forms/XamarinDemo/XamarinDemo/XamarinDemo/DemoPages 的StackLayoutExample

Children

StackLayout的Children定义是

// 摘要:
//     Gets an IList<View> of child element of the Layout.
public IList<T> Children { get; }

所以Children可以装下View的集合，不止是Label，也可以是ListView等等

示例

var listView = new Xamarin.Forms.ListView
{
    RowHeight = 40
};
listView.ItemsSource = new string[]
{
    "Buy pears",
    "Buy oranges",
    "Buy mangos",
    "Buy apples",
    "Buy bananas"
};
Content = new StackLayout
{
    VerticalOptions = LayoutOptions.FillAndExpand,
    Children = { listView }
};

示例代码

https://github.com/zLulus/NotePractice/tree/dev3/Xamarin.Forms/XamarinDemo/XamarinDemo/XamarinDemo/DemoPages 的StackLayoutExample 的ListViewInStackLayout

Tips

同时设置xaml和cs代码,哪个在后面，以哪个为准，相当于被覆盖了