01. Double click to trigger "System search" and drop Down "Notification Center"

After Windows Phone 8.1, when a foreground app is in full screen mode, the user needs to double-click the Phone Search button to display the search box.

This is to prevent users from "accidentally triggering" the search operation. The App can be programmed to show "Full-screen" mode.

Before WP8, many users complained that when playing a game or watching a video, the game or video was paused due to a "wrong touch" of the search key. If

The app is able to turn on the "double click Trigger" interaction, which is believed to enhance the user experience.

1) Double-click the Search button to open the system search:

(on wp8.1, turn on system search, set the system "location" to off, otherwise start Cortana by default.) But double-click the same effect)

2) two times "swipe down" to open the System "Notification Center"

Full-screen mode, which is turned on by default in the following cases:

1) Photo view (Photo Viewer)

2) Video viewing (Visual Viewer)

3) photograph (caputring a photo)

4) All types of "games" apps (any apps in with the game category)

The default interval time for two clicks is 2500 milliseconds. Therefore, when the app is in full-screen mode,

You must double-click the "Search" button two times within 2500 milliseconds to trigger a search. This default time

Can be modified by modifying the system's registry (customholddelays value, in milliseconds):

Hkey_local_machine\software\microsoft\shell\customholddelays

This setting is not visible to users of the app.

Another effect of this change is that when the app is in Full-screen mode, the user must "swipe down" two times

To open the notification hub.

MediaElement example (on a mobile phone running on a wp8.1 system):

1. In WP8 's Silverlight project

1) If you just add a MediaElement control in XAML, you cannot start the "Full-screen" mode:

<x:name= "LayoutRoot"  Background= "Transparent">    <Source= "Li Yugang. mp4"  AutoPlay= "True"   /> </ Grid >

2) using System Task, call the system player, default is "Full-screen" mode:

New Microsoft.Phone.Tasks.MediaPlayerLauncher (); // the path is the system installation package. If it is medialocationtype.data, you can specify the network path l.location =new Uri (" li Yugang. mp4" //  Display all system player button l.show ();  

2. In the Store project of wp8.1

1) If you just set the MediaElement "Full Screen" property to Isfullwindow= "True" , you cannot turn on the "Full-screen" mode

< Grid >    <  Source= "Li Yugang. mp4"  AutoPlay= "True"  Isfullwindow = "True" /> </ Grid >

The aretransportcontrolsenabled property needs to be set to true, that is, the default control of MediaElement is used to turn on the "Full-screen" mode:

< Grid >    <  aretransportcontrolsenabled= "True"  Source= "Li Yugang. mp4"  AutoPlay  = "true"  isfullwindow= "true"/>  </ Grid >

Display effect:

2) Open with system player, start "Full-screen" mode by default:

Async void Mainpage_loaded (object  sender, RoutedEventArgs e) {    //  read video files in the installation package, root directory    await Windows.ApplicationModel.Package.Current.InstalledLocation.GetFileAsync ("  Li Yugang. mp4");     await Windows.System.Launcher.LaunchFileAsync (file);                        }

01. Double click to trigger "System search" and drop Down "Notification Center"