Question

我一直很难在我的wp8.1应用中显示SystemMediaTransportControls，不幸的是它无法正常工作。这是场景，我添加了Windows Phone App Project，然后添加了Windows运行时组件（Windows Phone）。我在Myproject中引用了Runtime Component，然后在manifest中添加了Audio作为后台任务。一切似乎工作正常，媒体在后台播放，但SystemMediaTransportControls不显示。下面是我在BackgroundTask中运行方法的代码

public void Run(IBackgroundTaskInstance taskInstance)
        {
            Debug.WriteLine("Background Audio Task " + taskInstance.Task.Name + " starting...");

            taskInstance.Canceled += TaskInstance_Canceled;
            //taskInstance.Task.Completed += Taskcompleted;

            systemmediatransportcontrol = SystemMediaTransportControls.GetForCurrentView();
            systemmediatransportcontrol.ButtonPressed += systemmediatransportcontrol_ButtonPressed;
            systemmediatransportcontrol.PropertyChanged += systemmediatransportcontrol_PropertyChanged;

            systemmediatransportcontrol.IsEnabled = true;
            systemmediatransportcontrol.IsPauseEnabled = true;
            systemmediatransportcontrol.IsPlayEnabled = true;
            systemmediatransportcontrol.IsNextEnabled = true;
            systemmediatransportcontrol.IsPreviousEnabled = true;

            BackgroundMediaPlayer.Current.CurrentStateChanged += Current_CurrentStateChanged;
            BackgroundMediaPlayer.MessageReceivedFromForeground += BackgroundMediaPlayer_MessageReceivedFromForeground;

            Debug.WriteLine(systemmediatransportcontrol.IsEnabled.ToString());

            ValueSet message = new ValueSet();
            message.Add("backgroundStarted", "1");
            BackgroundMediaPlayer.SendMessageToForeground(message);

            BackgroundTaskStarted.Set();
            deferral = taskInstance.GetDeferral();
        }

在这个问题上工作了两天，这给我带来了很多麻烦。问题是，为什么SystemMediaTransportControls没有显示？

Answer 1

使用SystemMediaTransportControls.DisplayUpdater设置MusicProperties。 MusicProperties的类型为MusicDisplayProperties，包括歌曲标题和歌曲艺术家等属性。在轨道更改中更新此内容：

systemmediatransportcontrol.PlaybackStatus = MediaPlaybackStatus.Playing;
systemmediatransportcontrol.DisplayUpdater.Type = MediaPlaybackType.Music;
systemmediatransportcontrol.DisplayUpdater.MusicProperties.Title = "<Track_Name>";
systemmediatransportcontrol.DisplayUpdater.MusicProperties.Artist = "<Artist_Name>";
systemmediatransportcontrol.DisplayUpdater.Update();

SystemMediaTransportControls未出现在WP 8.1中

1 个答案: