Android（四十五）：Service - StartService、StopService实现媒体播放

Android（四十五）：Service - StartService、StopService实现媒体播放 实现媒体播放（与直接播放媒体资源的对比）

• 目录结构
  

源码 布局

• Resources/layout/main.xml

• Resources/layout/music_dialog.xml

服务 scripts/MusicService.cs

using Android.App;
using Android.Content;
using Android.Media;
using Android.OS;
using Android.Util;

namespace android_by_csharp.scripts
{
    [Service]
    public class MusicService : Service
    {
        private string TAG = nameof(MusicService);
        public static bool IsPlay; // 记录播放状态
        private MediaPlayer _player; // MediaPlayer对象
        public override void OnCreate()
        {
            base.OnCreate();
            _player = MediaPlayer.Create(this, Resource.Raw.music);
            Log.Debug(TAG, $"{TAG} ---> OnCreate");
        }

        public override StartCommandResult OnStartCommand(Intent intent, StartCommandFlags flags, int startId)
        {
            if (!_player.IsPlaying)
            {
                _player.Start();
                IsPlay = _player.IsPlaying;
            }
            Log.Debug(TAG, $"{TAG} ---> OnStartCommand");
            return base.OnStartCommand(intent, flags, startId);
        }
        
        public override void OnDestroy()
        {
            base.OnDestroy();
            _player.Stop();
            IsPlay = _player.IsPlaying;
            _player.Release(); // 释放资源
            Log.Debug(TAG, $"{TAG} ---> OnDestroy");
        }

        public override IBinder OnBind(Intent intent)
        {
            return null;
        }
    }
}

Activity scripts/MusicActivity.cs

using Android.App;
using Android.Content;
using Android.Media;
using Android.OS;
using Android.Util;
using Android.Widget;

namespace android_by_csharp.scripts
{
    [Activity(Label = "MusicActivity", Theme = "@style/MusicActivityTheme")]
    public class MusicActivity : Activity
    {
        protected override void OnCreate(Bundle savedInstanceState)
        {
            base.OnCreate(savedInstanceState);
            SetContentView(Resource.Layout.music_dialog);

            // 服务下的媒体播放（页面执行销毁后音乐还在，再次点击按钮会停止音乐的服务）
            var playPauseBtn1 = FindViewById(Resource.Id.play_pause_btn1);
            if (playPauseBtn1 != null)
                playPauseBtn1.Click += (sender, args) =>
                {
                    var intent = new Intent(this, typeof(MusicService));
                    Log.Debug("IsPlay", $"IsPlay ---> {MusicService.IsPlay}");
                    if (!MusicService.IsPlay)
                        StartService(intent);
                    else
                        StopService(intent);
                };
            
            // 一般媒体播放（页面执行销毁后音乐还在，再次点击按钮不会停止音乐，而是会再次播放这个音乐资源，相当于重新创建了一个新的MediaPlayer）
            var playPauseBtn2 = FindViewById(Resource.Id.play_pause_btn2);
            var player = MediaPlayer.Create(this, Resource.Raw.music);
            if (playPauseBtn2 != null)
                playPauseBtn2.Click += (sender, args) =>
                {
                    if (player is { IsPlaying: false })
                        player.Start();
                    else
                        player?.Pause();
                };
        }
    }
}

Activity MainActivity.cs

using android_by_csharp.scripts;
using Android.App;
using Android.Content;
using Android.OS;
using Android.Widget;

namespace android_by_csharp
{
    
    [Activity(Label = "@string/app_name", Theme = "@style/AppTheme", MainLauncher = true)]
    public class MainActivity : Activity
    {
        protected override void OnCreate(Bundle savedInstanceState)
        {
            base.OnCreate(savedInstanceState);
            SetContentView(Resource.Layout.main);

            var btn01 = FindViewById(Resource.Id.btn01);
            if (btn01 != null) btn01.Click += (sender, args) => StartActivity(new Intent(this, typeof(MusicActivity)));
        }
    }
}