PyQt重写QMediaPlayer和QMediaPlaylist

╰+攻爆jí腚メ 2022-10-16 07:23 15阅读 0赞

在做一个本地视频播放器，做到删除播放列表的时候发现Qt自带的QMediaPlaylist有个bug。  
用removeMedia()进行删除操作。  
如果播放列表中某一项正在播放，删除这个项之后的任意项都没问题。  
但是如果删除这一项之前的某一项，当前索引会发生变化，然后正在播放的内容会停止。  
C++代码运行出来也是一样的。  
没找到解决方案，所以只能重写了。

时间仓促，只实现了一些常用的方法。比如说上一个，下一个，设置模式，添加移除媒体等等。  
MyPlaylist.py

from typing import Iterable
    from PyQt5.QtCore import QUrl, pyqtSignal, QObject
    from PyQt5.QtMultimedia import QMediaPlayer, QMediaContent
    import random
    
    '''自定义播放列表'''
    class MyPlaylist(QObject):
        playbackModeChanged = pyqtSignal(int)
        currentIndexChanged = pyqtSignal(int)
        currentMediaChanged = pyqtSignal(object)
        def __init__(self,player):
            super(MyPlaylist, self).__init__()
            # 真正的播放器对象
            self.player = player
            # 播放列表
            self.__playlist = []
            # 媒体不存在时的默认值，常量
            self.__DEFAULT_MEDIA_CONTENT = QMediaContent(QUrl(''))
            # 默认索引是-1
            self.setCurrentIndex(-1)
            # 默认播放模式是顺序播放
            self.__playbackMode = MyPlaylist.Sequential
            # 连接媒体状态改变信号
            self.player.mediaStatusChanged.connect(self.__handleMediaStatusChanged)
    
        def clear(self):
            """清空"""
            self.__playlist = []
            self.setCurrentIndex(-1)
    
        def isEmpty(self):
            """是否为空"""
            return self.mediaCount() == 0
    
        def media(self,pos):
            """获取pos对应的媒体对象"""
            # 如果索引值合法，从列表中获取媒体
            if 0 <= pos < self.mediaCount():
                return self.__playlist[pos]
            else:
                # 否则返回默认的媒体
                return self.__DEFAULT_MEDIA_CONTENT
    
        def mediaCount(self):
            return len(self.__playlist)
    
        def addMedia(self,content):
            """添加媒体"""
            # 根据参数类型，进行不同的处理
            if isinstance(content,QMediaContent):
                '''addMedia(self, QMediaContent)'''
                self.__playlist.append(content)
            elif isinstance(content,Iterable):
                '''addMedia(self, Iterable[QMediaContent])'''
                self.__addIterableMedia(content)
            else:
                self.__raiseAddMediaTypeError(content)
    
        def removeMedia(self,pos):
            """移除媒体"""
            if 0 <= pos < self.mediaCount():
                # 如果删除的是当前媒体，需要重新从列表中取值
                if pos == self.__currentIndex:
                    self.player.setMedia(self.currentMedia())
                del self.__playlist[pos]
                return True
            return False
    
        def playbackMode(self):
            """获取播放模式"""
            return self.__playbackMode
    
        def setPlaybackMode(self,playBackMode):
            """设置播放模式"""
            self.__playbackMode = playBackMode
            self.playbackModeChanged.emit(playBackMode)
    
        def currentIndex(self):
            """获取当前索引值"""
            return self.__currentIndex
    
        def currentMedia(self):
            """获取当前媒体"""
            if self.__currentIndex == -1:
                # 如果当前索引值是-1，返回默认的媒体
                return self.__DEFAULT_MEDIA_CONTENT
            elif 0 <= self.__currentIndex < self.mediaCount():
                # 根据当前索引值去列表中取媒体
                return self.__playlist[self.__currentIndex]
            else:
                # 索引不合法，返回默认媒体
                return self.__DEFAULT_MEDIA_CONTENT
    
        def setCurrentIndex(self,currentIndex):
            """设置当前索引值"""
            # 如果索引值合法，从列表中获取媒体
            if 0 <= currentIndex < self.mediaCount():
                self.__currentIndex = currentIndex
            else:
                # 索引值不合法，返回-1
                self.__currentIndex = -1
            self.currentIndexChanged.emit(currentIndex)
            self.__setMedia()
    
        def previousIndex(self,steps = 1):
            """获取前一个媒体索引值"""
            if self.__playbackMode == MyPlaylist.CurrentItemOnce:
                # 单曲播放
                return -1
            elif self.__playbackMode == MyPlaylist.CurrentItemInLoop:
                # 单曲循环
                return self.__currentIndex
            elif self.__playbackMode == MyPlaylist.Sequential:
                # 顺序播放
                newIndex = self.__currentIndex - 1
                if newIndex > 0:
                    return newIndex
                else:
                    return -1
            elif self.__playbackMode == MyPlaylist.Loop:
                # 列表循环
                return (self.__currentIndex - steps) % self.mediaCount()
            elif self.__playbackMode == MyPlaylist.Random:
                # 随机播放
                return random.randint(0, self.mediaCount()-1)
    
        def nextIndex(self,steps = 1):
            """获取下一个媒体索引值"""
            if self.__playbackMode == MyPlaylist.CurrentItemOnce:
                # 单曲播放
                return -1
            elif self.__playbackMode == MyPlaylist.CurrentItemInLoop:
                # 单曲循环
                return self.__currentIndex
            elif self.__playbackMode == MyPlaylist.Sequential:
                # 顺序播放
                newIndex = self.__currentIndex + steps
                if newIndex < self.mediaCount():
                    return newIndex
                else:
                    return -1
            elif self.__playbackMode == MyPlaylist.Loop:
                # 列表循环
                return (self.__currentIndex + steps) % self.mediaCount()
            elif self.__playbackMode == MyPlaylist.Random:
                # 随机播放
                return random.randint(0, self.mediaCount()-1)
    
        def previous(self):
            """播放器切换到前一个媒体"""
            self.__currentIndex = self.previousIndex()
            self.__setMedia()
    
        def next(self):
            """播放器切换到下一个媒体"""
            # 获取下一个索引值，并设置为当前值
            self.__currentIndex = self.nextIndex()
            # 设置为播放器的当前媒体
            self.__setMedia()
    
        def __setMedia(self):
            """将当前媒体设置到播放器对象中"""
            media = self.currentMedia()
            self.player.setMedia(media)
            self.currentMediaChanged.emit(media)
    
        def __addIterableMedia(self,content):
            """重载addMedia方法，接收数组参数"""
            for item in content:
                if isinstance(item,QMediaContent):
                    self.__playlist.append(item)
                else:
                    self.__raiseAddMediaTypeError(item)
    
        def __handleMediaStatusChanged(self,mediaStatus):
            # 当前媒体播放结束，获取下一个，重新播放
            if mediaStatus == QMediaPlayer.EndOfMedia:
                # 切换下一个媒体
                self.next()
                # 如果返回-1，表示不需要再次播放
                if self.__currentIndex != -1:
                    # 否则重新播放下一个
                    self.player.play()
    
        @staticmethod
        def __raiseAddMediaTypeError(content):
            """addMedia方法参数不合法，抛出类型错误"""
            typeStr = str(type(content))
            typeStr = typeStr[7:len(typeStr)-1]
            raise TypeError(f'''arguments did not match any overloaded call:
      addMedia(self, QMediaContent): argument 1 has unexpected type {
          typeStr}
      addMedia(self, Iterable[QMediaContent]): argument 1 has unexpected type {
          typeStr}''')
    
        AccessDeniedError = 4
        CurrentItemInLoop = 1
        CurrentItemOnce = 0
        FormatError = 1
        FormatNotSupportedError = 2
        Loop = 3
        NetworkError = 3
        NoError = 0
        Random = 4
        Sequential = 2

MyPlayer.py

from PyQt5.QtMultimedia import QMediaPlayer
    
    '''自定义播放器类'''
    class MyPlayer(QMediaPlayer):
        def __init__(self):
            super(MyPlayer, self).__init__()
            self.playlist = None
    
        def play(self):
            # 如果是暂停重新播放，直接调用父类的方法，防止进度不对
            if not self.state() == QMediaPlayer.PausedState:
                self.setMedia(self.playlist.currentMedia())
                if self.playlist.currentIndex() == -1:
                    self.playlist.setCurrentIndex(0)
            super(MyPlayer, self).play()
    
        def setPlaylist(self, playlist):
            """覆盖父类的setPlaylist，设置自定义的playlist"""
            self.playlist = playlist
            self.setMedia(self.playlist.currentMedia())

调用代码实例

self.player = MyPlayer()
    # 注意该类在内部会对播放器做一些处理，因此构造的时候就要把播放器对象传进去
    self.myPlayList = MyPlaylist(self.player)
    self.player.setPlaylist(self.myPlayList)