我在Windows Phone 8.1（非SilverLight）应用程序中工作。我有一个播放音频文件的MediaElement AudioPlayerSeek。我还有一个滑块private DispatcherTimer _timer;
private bool _sliderpressed = false;
// Constructor
public MainPage()
{
InitializeComponent();
NavigationCacheMode = NavigationCacheMode.Required;
AudioPlayerSeek.ValueChanged += AudioPlayerSeek_ValueChanged;
InitializeAudioRecording();
DataContext = App.ViewModel;
}
// Called when I select my Audio file in the ListView
private async void Selector_OnSelectionChanged(object sender, SelectionChangedEventArgs e)
{
// Cast to XAML ListView
var listView = sender as ListView;
// Verify we have ListView
if (listView == null) { return; }
var listVmItem = listView.SelectedItem as RecordFileVm;
if (listVmItem != null)
{
var file2 = await _finalStorageFolder.GetFileAsync(listVmItem.FileName);
var stream = (await file2.OpenReadAsync()).AsStream().AsRandomAccessStream();
AudioPlayer.SetSource(stream, file2.ContentType);
TimeSpan recordingTime = AudioPlayer.NaturalDuration.TimeSpan;
AudioPlayerSeek.Maximum = recordingTime.TotalSeconds;
AudioPlayerSeek.SmallChange = 1;
AudioPlayerSeek.LargeChange = Math.Min(10, recordingTime.Seconds / 10);
AudioPlayer.MediaOpened += AudioPlayer_MediaOpened;
AudioPlayer.CurrentStateChanged += AudioPlayer_CurrentStateChanged;
AudioPlayer.Play();
}
// Clear selection
listView.SelectedItem = null;
}
private double SliderFrequency(TimeSpan timevalue)
{
double stepfrequency = -1;
double absvalue = (int)Math.Round(timevalue.TotalSeconds, MidpointRounding.AwayFromZero);
stepfrequency = (int)(Math.Round(absvalue / 100));
if (timevalue.TotalMinutes >= 10 && timevalue.TotalMinutes < 30)
{
stepfrequency = 10;
}
else if (timevalue.TotalMinutes >= 30 && timevalue.TotalMinutes < 60)
{
stepfrequency = 30;
}
else if (timevalue.TotalHours >= 1)
{
stepfrequency = 60;
}
if (stepfrequency == 0) stepfrequency += 1;
if (stepfrequency == 1)
{
stepfrequency = absvalue / 100;
}
return stepfrequency;
}
void AudioPlayerSeek_ValueChanged(object sender, RangeBaseValueChangedEventArgs e)
{
if (!_sliderpressed)
{
AudioPlayer.Position = TimeSpan.FromSeconds(e.NewValue);
}
}
private void SetupTimer()
{
_timer = new DispatcherTimer();
_timer.Interval = TimeSpan.FromSeconds(AudioPlayerSeek.StepFrequency);
StartTimer();
}
private void _timer_Tick(object sender, object e)
{
if (!_sliderpressed)
{
AudioPlayerSeek.Value = AudioPlayer.Position.TotalSeconds;
}
}
private void StartTimer()
{
_timer.Tick += _timer_Tick;
_timer.Start();
}
，我希望“挂钩”到MediaElement，以便它在播放音频时移动。
我逐字逐句地了解了this tutorial，但仍无法让它发挥作用。当我播放音频（点击ListView中的某个项目）时，播放音频，但滑块不会移动！
myHolder.sb_songProgress.setProgress((int) timeElapsed);
我相信这是相关的代码。有人可以告诉我如何同步滑块以使其随播放媒体（音频）一起移动。
谢谢。
答案 0 :(得分：1)
您正在以错误的顺序进行设置。尝试将其更改为：
if (listVmItem != null)
{
var file2 = await _finalStorageFolder.GetFileAsync(listVmItem.FileName);
var stream = (await file2.OpenReadAsync()).AsStream().AsRandomAccessStream();
AudioPlayer.MediaOpened += AudioPlayer_MediaOpened;
AudioPlayer.CurrentStateChanged += AudioPlayer_CurrentStateChanged;
AudioPlayer.SetSource(stream, file2.ContentType);
AudioPlayer.Play();
}
并将这些调用移至MediaOpened处理程序：
TimeSpan recordingTime = AudioPlayer.NaturalDuration.TimeSpan;
AudioPlayerSeek.Maximum = recordingTime.TotalSeconds;
AudioPlayerSeek.SmallChange = 1;
AudioPlayerSeek.LargeChange = Math.Min(10, recordingTime.Seconds / 10);