UWP：使用MediaPlayerElement实现媒体播放器

1.代码部分

<Page
x:Class="Homework8.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:Homework8"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:c="using:Homework8.Converter"
mc:Ignorable="d">
<Page.Resources>
<c:timeLineConverter x:Key="converter" />
<Storyboard x:Name="EllStoryboard" RepeatBehavior="Forever">
<DoubleAnimation Duration="0:0:20"
To="360"
Storyboard.TargetProperty="(UIElement.RenderTransform).(CompositeTransform.Rotation)"
Storyboard.TargetName="Picture"
d:IsOptimized="True"/>
</Storyboard>
</Page.Resources>

<Page.BottomAppBar>
<CommandBar>
<AppBarButton Name="start" Icon="Play" FontSize="20" Click="start_Click" HorizontalAlignment="Left" Label="播放"/>
<AppBarButton Name="pause" Icon="Pause" FontSize="20" Click="pause_Click" Label="暂停"/>
<AppBarButton Name="stop" Icon="Stop" FontSize="20" Click="stop_Click" Label="停止"/>
<AppBarButton Name="add" Icon="OpenFile" FontSize="20" Click="add_Click" Label="选择文件"/>
<AppBarButton Name="display" Icon="FullScreen" FontSize="20" Click="display_Click" Label="全屏"/>
</CommandBar>
</Page.BottomAppBar>

<Grid Name="MyGrid">
<Grid.Background>
<ImageBrush ImageSource="Assets/3.jpg" Opacity="0.5" />
</Grid.Background>
<Grid.RowDefinitions>
<RowDefinition Height="auto" />
<RowDefinition Height="*" />
<RowDefinition Height="auto" />
</Grid.RowDefinitions>
<TextBlock Name="Title" Text="MediaPlayer" Margin="25" Style="{StaticResource HeaderTextBlockStyle}" FontWeight="Bold" HorizontalAlignment="Center" />

<Ellipse Width="450" Height="450" Margin="75,45,75,45"
Grid.Row="1" Name="Picture" Visibility="Collapsed"
VerticalAlignment="Center" HorizontalAlignment="Center"
RenderTransformOrigin="0.5, 0.5">
<Ellipse.RenderTransform>
<CompositeTransform />
</Ellipse.RenderTransform>
<Ellipse.Fill>
<ImageBrush ImageSource="Assets/2.jpg"/>
</Ellipse.Fill>

</Ellipse>

<MediaPlayerElement x:Name="_mediaPlayerElement" AreTransportControlsEnabled="False" HorizontalAlignment="Stretch"  Grid.Row="1"/>
<StackPanel Grid.Row="2">
<Slider Padding="50,0,50,0" x:Name="timeLine"
Value="{x:Bind _mediaTimelineController.Position, Converter={StaticResource converter},Mode=TwoWay}"/>
<StackPanel  Orientation="Horizontal">
<AppBarButton Icon="Volume" IsCompact="True" VerticalAlignment="center" Margin="30,0,0,0"/>
<Slider Minimum="0" Maximum="1" Name="Volumn" Width="70" Value="0.5" StepFrequency="0.1" ValueChanged="Volumn_ValueChanged" />
</StackPanel>
</StackPanel>
</Grid>
</Page>

using Windows.UI.Xaml.Controls.Primitives;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Input;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Media.Imaging;
using Windows.UI.Xaml.Navigation;

//“空白页”项模板在 http://go.microsoft.com/fwlink/?LinkId=402352&clcid=0x409 上有介绍

namespace Homework8
{
/// <summary>
/// 可用于自身或导航至 Frame 内部的空白页。
/// </summary>
public sealed partial class MainPage : Page
{
MediaPlayer _mediaPlayer = new MediaPlayer();
MediaTimelineController _mediaTimelineController = new MediaTimelineController();
TimeSpan _duration;
// MediaPlaybackSession _mediaPlaybackSession = new MediaPlaybackSession();
public MainPage()
{
this.InitializeComponent();
var mediaSource = MediaSource.CreateFromUri(new Uri("ms-appx:///Assets/Video1.MP4"));
mediaSource.OpenOperationCompleted += MediaSource_OpenOperationCompleted;
_mediaPlayer.Source = mediaSource;
_mediaPlayer.CommandManager.IsEnabled = false;
_mediaPlayer.TimelineController = _mediaTimelineController;
//_mediaPlayer.Play();
_mediaPlayerElement.SetMediaPlayer(_mediaPlayer);
}

private void pause_Click(object sender, RoutedEventArgs e)
{
try
{
if (_mediaTimelineController.State == MediaTimelineControllerState.Running)
{
EllStoryboard.Pause();
_mediaTimelineController.Pause();
}
else
{
//EllStoryboard.Resume();
EllStoryboard.Begin();
_mediaTimelineController.Resume();
}
}
catch
{

}
}

private void start_Click(object sender, RoutedEventArgs e)
{
try
{
DispatcherTimer timer = new DispatcherTimer();
timer.Interval = TimeSpan.FromSeconds(1);
timer.Tick += timer_Tick;
timer.Start();
EllStoryboard.Begin();
_mediaTimelineController.Start();
}
catch {

}

}
void timer_Tick(object sender, object e) {
timeLine.Value = ((TimeSpan)_mediaTimelineController.Position).TotalSeconds;
if (timeLine.Value == timeLine.Maximum) {
_mediaTimelineController.Position = TimeSpan.FromSeconds(0);
_mediaTimelineController.Pause();
EllStoryboard.Stop();
}
}
private void stop_Click(object sender, RoutedEventArgs e)
{
try
{
_mediaTimelineController.Position = TimeSpan.FromSeconds(0);
_mediaTimelineController.Pause();
EllStoryboard.Stop();
}
catch {

}

}

private void display_Click(object sender, RoutedEventArgs e)
{
ApplicationView view = ApplicationView.GetForCurrentView();
bool isInFullScreenMode = view.IsFullScreenMode;
if (isInFullScreenMode)
{
ImageBrush imageBrush = new ImageBrush();
imageBrush.ImageSource = new BitmapImage(new Uri("ms-appx:///Assets/3.jpg", UriKind.Absolute));
MyGrid.Background = imageBrush;
MyGrid.Background.Opacity = 0.5;
view.ExitFullScreenMode();
}
else {
MyGrid.Background = new SolidColorBrush(Colors.Black);// Windows.UI.Xaml.Media.Brush
view.TryEnterFullScreenMode();
}
}

private async void add_Click(object sender, RoutedEventArgs e)
{
var openPicker = new FileOpenPicker();

openPicker.SuggestedStartLocation = Windows.Storage.Pickers.PickerLocationId.VideosLibrary;
openPicker.FileTypeFilter.Add(".wmv");
openPicker.FileTypeFilter.Add(".mp4");
openPicker.FileTypeFilter.Add(".mp3");
openPicker.FileTypeFilter.Add(".wma");

StorageFile file = await openPicker.PickSingleFileAsync();
if (file != null) {
var mediaSource = MediaSource.CreateFromStorageFile(file);
mediaSource.OpenOperationCompleted += MediaSource_OpenOperationCompleted;
_mediaPlayer.Source = mediaSource;
if (file.FileType == ".mp3" || file.FileType == ".wma")
{
Picture.Visibility = Visibility.Visible;
//_mediaPlayerElement.Visibility = Visibility.Collapsed;
}
else {
Picture.Visibility = Visibility.Collapsed;
//_mediaPlayerElement.Visibility = Visibility.Visible;
}
}

}

private void Volumn_ValueChanged(object sender, RangeBaseValueChangedEventArgs e)
{
_mediaPlayer.Volume = (double)Volumn.Value;
}

private async void MediaSource_OpenOperationCompleted(MediaSource sender, MediaSourceOpenOperationCompletedEventArgs args)
{
_duration = sender.Duration.GetValueOrDefault();

await Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal, () =>
{
timeLine.Minimum = 0;
timeLine.Maximum = _duration.TotalSeconds;
timeLine.StepFrequency = 1;
});
}
}
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Windows.UI.Xaml.Data;

namespace Homework8.Converter
{
class timeLineConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, string language)
{
return ((TimeSpan)value).TotalSeconds;
}

public object ConvertBack(object value, Type targetType, object parameter, string language)
{
return TimeSpan.FromSeconds((double)value);
}
}
}

2.实现过程(截图来自我的实验报告)