Xamarin form:如何在异步任务中即时显示活动指示器？

<StackLayout>
    <ActivityIndicator x:Name="activityIndicator" IsRunning="False" />
    <!-- 其他控件 -->
</StackLayout>

activityIndicator.IsRunning = true;

activityIndicator.IsRunning = false;

<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="YourNamespace.YourPage">
    <StackLayout>
        <ActivityIndicator x:Name="activityIndicator" IsRunning="False" />
        <!-- 其他控件 -->
    </StackLayout>
</ContentPage>

using Xamarin.Forms;

namespace YourNamespace
{
    public partial class YourPage : ContentPage
    {
        public YourPage()
        {
            InitializeComponent();
        }

        private async void YourButton_Clicked(object sender, EventArgs e)
        {
            activityIndicator.IsRunning = true;

            // 异步任务
            await YourAsyncTask();

            activityIndicator.IsRunning = false;
        }

        private async Task YourAsyncTask()
        {
            // 异步任务的代码
            await Task.Delay(2000); // 模拟耗时操作
        }
    }
}