maui 开发音乐播放APP 优化（2）

界面改为：

音量可以调整 。同时当前状态 显示。以及播放音乐.视频有时可以自动播放有时候要手动。

界面代码

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:toolkit="http://schemas.microsoft.com/dotnet/2022/maui/toolkit"
             x:Class="video.MainPage"
                Title="视频音频播放示例">
    <ScrollView>
        <VerticalStackLayout
			Spacing="25"
			Padding="30,0"
			VerticalOptions="Center">
            <Button  x:Name="btn" Text="播放音乐" Clicked="Button_Clicked" />
            <toolkit:MediaElement x:Name="audioMediaElement"
                      IsVisible="False"
                      Source="embed://3773192759.mp3"
                      />
            <toolkit:MediaElement x:Name="videoMediaElement"
                Loaded="videoMediaElement_Loaded"
                ShouldAutoPlay="True"
                Aspect="AspectFill"
                Source="embed://AndroidVideo.mp4"/>
            <HorizontalStackLayout>
                <Label FontAttributes="Bold"  Text="Volume" />
                <Slider Maximum="1.0"
                    Minimum="0.0"
                    Margin="10,0,10,0"
                    Value="{Binding Volume}"
                    WidthRequest="300" />
                <Label Text="{Binding Volume, StringFormat='{0:F2}'}" />
                <Label FontAttributes="Bold" Text="Position:"
                       Margin="10,0,10,0"/>
                <Label Text="{Binding Position}" />
                <Label FontAttributes="Bold" Text="State:"
                       Margin="10,0,10,0"/>
                <Label Text="{Binding State}" />
                <Label FontAttributes="Bold" Text="Media Status:"
                       Margin="10,0,10,0"/>
                <Label Text="{Binding MediaStatus}" />
            </HorizontalStackLayout>
        </VerticalStackLayout>
    </ScrollView>
</ContentPage>

C#的代码：

using CommunityToolkit.Maui.Core.Primitives;
using CommunityToolkit.Maui.Views;
namespace video;
public static class Extensions
{
    public static string ToShortTimeString(this TimeSpan t)
    {
        string ret = "";

        // 小时部分
        if (t.Hours > 0)
            ret = $"{t.Hours}:";

        // 分钟部分
        if (t.TotalMinutes > 0)
        {
            if (t.Hours == 0)
                ret += $"{t.Minutes}:";
            else
                ret += $"{t.Minutes.ToString("D2")}:";
        }
        // 秒部分
        if (t.TotalSeconds > 0)
            ret += $"{t.Seconds.ToString("D2")}";
        else
            ret += "00";
        return ret;
    }
}
public partial class MainPage : ContentPage
{
    private string mediaStatus = string.Empty;


    // 媒体状态属性
    public string MediaStatus
    {
        get => mediaStatus;
        private set
        {
            mediaStatus = value;
            OnPropertyChanged(nameof(MediaStatus));
        }
    }


   
    // 播放器状态属性
    public string State
    {
        get
        {
            if (videoMediaElement != null)
            {
                return Enum.GetName(typeof(MediaElementState), videoMediaElement.CurrentState);
            }
            else
                return "";
        }
    }
    // 媒体状态属性
    public string Position
    {
        get
        {
            if (videoMediaElement != null)
            {
                var pos = videoMediaElement.Position;
                var dur = videoMediaElement.Duration;
                // Using a TimeSpan extension method
                return pos.ToShortTimeString() + "/" + dur.ToShortTimeString();
            }
            else
                return "";
        }
    }
    // 音量属性
    public double Volume
    {
        get
        {
            try
            {
                if (videoMediaElement != null)
                {
                    return videoMediaElement.Volume;
                }
                else
                {
                    // You might want to handle the case when videoMediaElement is null.
                    // For now, returning 1 as a default value.
                    return 1;
                }
            }
            catch (NullReferenceException ex)
            {
                // Handle the exception (log, notify, etc.) based on your application's requirements.
                // For now, just log the exception.
                Console.WriteLine($"Error in Volume get: {ex.Message}");
                return 1;
            }
        }
        set
        {
            bool setFlag = false;
            try
            {
                if (videoMediaElement != null && videoMediaElement.Volume != value)
                {
                    videoMediaElement.Volume = value;
                    setFlag = true;
                }
                if (audioMediaElement != null && audioMediaElement.Volume != value)
                {
                    audioMediaElement.Volume = value;
                    setFlag = true;
                }
            }
            catch (NullReferenceException ex)
            {
                // Handle the exception (log, notify, etc.) based on your application's requirements.
                // For now, just log the exception.
                Console.WriteLine($"Error in Volume set: {ex.Message}");
            }

            if (setFlag)
            {
                OnPropertyChanged(nameof(Volume));
            }
        }
    }

    // 构造函数
    public MainPage()
    {
        // 设置数据绑定上下文为当前页面
        BindingContext = this;
        // 初始化页面组件
        InitializeComponent();
    }
    // 播放器位置变化事件
    private void VideoMediaElement_PositionChanged(object sender, MediaPositionChangedEventArgs e)
    {
        OnPropertyChanged(nameof(Position));
    }
    // 播放按钮点击事件
    private void Button_Clicked(object sender, EventArgs e)
    {
      


        if (audioMediaElement.CurrentState == CommunityToolkit.Maui.Core.Primitives.MediaElementState.Playing)
        {
            audioMediaElement.Pause();
            btn.Text = "暂停音乐";
        }

        else if (audioMediaElement.CurrentState == CommunityToolkit.Maui.Core.Primitives.MediaElementState.Paused)
        {
            audioMediaElement.Play();
            btn.Text = "播放音乐";
        }



    }

    // 播放器状态变化事件
    private void VideoMediaElement_StateChanged(object sender, MediaStateChangedEventArgs e)
    {
        OnPropertyChanged(nameof(State));
    }
    // 播放器加载事件
    private void videoMediaElement_Loaded(object sender, EventArgs e)
    {
        videoMediaElement.PositionChanged += VideoMediaElement_PositionChanged;
        videoMediaElement.StateChanged += VideoMediaElement_StateChanged;
        videoMediaElement.MediaOpened += VideoMediaElement_MediaOpened;
        videoMediaElement.MediaEnded += VideoMediaElement_MediaEnded;
        videoMediaElement.MediaFailed  += VideoMediaElement_MediaFailed;
    }
    // 播放器媒体加载失败事件
    private void VideoMediaElement_MediaFailed(object sender, MediaFailedEventArgs e)
    {
        MediaStatus = "媒体失败";
    }

    // 播放器媒体结束事件
    private void VideoMediaElement_MediaEnded(object sender, EventArgs e)
    {
        MediaStatus = "媒体 结束";
    }
    // 播放器媒体打开事件
    private void VideoMediaElement_MediaOpened(object sender, EventArgs e)
    {
        MediaStatus = "媒体 打开";
    }
}