MPRemoteCommandCenter锁屏控制问题：如何同时显示快进快退与上下曲按钮？

iOS 锁屏媒体控件的导航区域（左右两侧）仅各提供一个按钮位置，用于播放导航类命令。当同时启用 skipBackwardCommand/skipForwardCommand 和 previousTrackCommand/nextTrackCommand 时，iOS 会优先显示快进/快退命令，从而覆盖上一曲/下一曲按钮，导致后者无法在主锁屏界面显示。

根据需求，有两种可行的处理方式：

方式一：调整交互逻辑，将快进/快退设为上一曲/下一曲的长按操作 #

如果希望主界面优先显示上一曲/下一曲，可将快进/快退功能绑定到这两个按钮的长按事件上：

- (void)setupRemoteTransportControls {
    [[UIApplication sharedApplication] beginReceivingRemoteControlEvents];
    MPRemoteCommandCenter* commandCenter = [MPRemoteCommandCenter sharedCommandCenter];
    
    // 播放/暂停命令
    [commandCenter.playCommand setEnabled:YES];
    [commandCenter.playCommand addTarget:self action:@selector(playVideo)];
    [commandCenter.pauseCommand setEnabled:YES];
    [commandCenter.pauseCommand addTarget:self action:@selector(pauseVideo)];
    
    // 上一曲：点击切换曲目，长按执行快退
    [commandCenter.previousTrackCommand setEnabled:YES];
    [commandCenter.previousTrackCommand addTarget:self action:@selector(prevTrack)];
    
    MPRemoteCommandHandlerStatus (^skipBackwardHandler)(MPRemoteCommandEvent *) = ^MPRemoteCommandHandlerStatus(MPRemoteCommandEvent *event) {
        if ([event isKindOfClass:[MPSeekCommandEvent class]]) {
            [self skipBackward];
            return MPRemoteCommandHandlerStatusSuccess;
        }
        return MPRemoteCommandHandlerStatusNoActionPerformed;
    };
    [commandCenter.previousTrackCommand setLongPressAction:skipBackwardHandler];
    
    // 下一曲：点击切换曲目，长按执行快进
    [commandCenter.nextTrackCommand setEnabled:YES];
    [commandCenter.nextTrackCommand addTarget:self action:@selector(nextTrack)];
    
    MPRemoteCommandHandlerStatus (^skipForwardHandler)(MPRemoteCommandEvent *) = ^MPRemoteCommandHandlerStatus(MPRemoteCommandEvent *event) {
        if ([event isKindOfClass:[MPSeekCommandEvent class]]) {
            [self skipForward];
            return MPRemoteCommandHandlerStatusSuccess;
        }
        return MPRemoteCommandHandlerStatusNoActionPerformed;
    };
    [commandCenter.nextTrackCommand setLongPressAction:skipForwardHandler];
    
    // 播放进度调整命令
    [commandCenter.changePlaybackPositionCommand setEnabled:YES];
    [commandCenter.changePlaybackPositionCommand addTarget:self action:@selector(changedThumbSliderOnLockScreen:)];
    
    [[UIApplication sharedApplication] beginReceivingRemoteControlEvents];
}

方式二：使用自定义命令，将额外功能放入扩展菜单 #

如果必须保留四个独立按钮，可将其中一组命令设为自定义命令，用户点击锁屏控件的「⋯」按钮即可访问：

- (void)setupRemoteTransportControls {
    [[UIApplication sharedApplication] beginReceivingRemoteControlEvents];
    MPRemoteCommandCenter* commandCenter = [MPRemoteCommandCenter sharedCommandCenter];
    
    // 播放/暂停命令
    [commandCenter.playCommand setEnabled:YES];
    [commandCenter.playCommand addTarget:self action:@selector(playVideo)];
    [commandCenter.pauseCommand setEnabled:YES];
    [commandCenter.pauseCommand addTarget:self action:@selector(pauseVideo)];
    
    // 主界面显示上一曲/下一曲
    [commandCenter.previousTrackCommand setEnabled:YES];
    [commandCenter.previousTrackCommand addTarget:self action:@selector(prevTrack)];
    [commandCenter.nextTrackCommand setEnabled:YES];
    [commandCenter.nextTrackCommand addTarget:self action:@selector(nextTrack)];
    
    // 自定义快退命令（放入扩展菜单）
    MPCommandHandlerStatus (^customSkipBackwardHandler)(MPRemoteCommandEvent *) = ^MPCommandHandlerStatus(MPRemoteCommandEvent *event) {
        [self skipBackward];
        return MPCommandHandlerStatusSuccess;
    };
    MPRemoteCommand *customSkipBackwardCommand = [[MPRemoteCommand alloc] initWithCommandIdentifier:MPRemoteCommandIdentifierSkipBackward];
    [customSkipBackwardCommand setEnabled:YES];
    [customSkipBackwardCommand setLocalizedName:@"快退"];
    [customSkipBackwardCommand addTargetWithHandler:customSkipBackwardHandler];
    [commandCenter addCommand:customSkipBackwardCommand];
    
    // 自定义快进命令（放入扩展菜单）
    MPCommandHandlerStatus (^customSkipForwardHandler)(MPRemoteCommandEvent *) = ^MPCommandHandlerStatus(MPRemoteCommandEvent *event) {
        [self skipForward];
        return MPCommandHandlerStatusSuccess;
    };
    MPRemoteCommand *customSkipForwardCommand = [[MPRemoteCommand alloc] initWithCommandIdentifier:MPRemoteCommandIdentifierSkipForward];
    [customSkipForwardCommand setEnabled:YES];
    [customSkipForwardCommand setLocalizedName:@"快进"];
    [customSkipForwardCommand addTargetWithHandler:customSkipForwardHandler];
    [commandCenter addCommand:customSkipForwardCommand];
    
    // 播放进度调整命令
    [commandCenter.changePlaybackPositionCommand setEnabled:YES];
    [commandCenter.changePlaybackPositionCommand addTarget:self action:@selector(changedThumbSliderOnLockScreen:)];
    
    [[UIApplication sharedApplication] beginReceivingRemoteControlEvents];
}

• iOS 锁屏媒体控件的布局由系统固定，主界面仅支持有限的命令按钮显示，无法同时容纳两组导航类命令（快进/快退 + 上一曲/下一曲）。
• 自定义命令会被归类到扩展菜单中，用户需要额外点击才能访问，但可以保留所有功能的独立性。

内容的提问来源于stack exchange，提问作者Rao