如何在Xamarin Forms和XAML中检测Tab显示/隐藏

Question

I am using following code to implement tabbed page in my xamarin forms app:

public class MainApp : TabbedPage
{
    public MainApp ()
    {
        this.Children.Add (new PanicPage{Title="Panic", Icon="icon_panic" });
        this.Children.Add (new StatusPage{Title="Status", Icon="icon_status" });
        this.Children.Add (new ConfigPage{Title="Config", Icon="icon_config"  });           
    }

}

I need to detect when particular tab is being shown or is it hidden. How can I do this in Xamarin forms?

Answer 1

有一个虚拟方法OnCurrentPageChanged重写此方法，然后检查CurrentPage属性

Answer 2

There is TabbedPage.CurrentPage property. You can either bind your view-model property to it or write code like this:

this.PropertyChanged += (sender, e) => {
    if (e.PropertyName == "CurrentPage")
    {
        //TODO
    }
};