Question

我正在为Spotify编写一个应用扩展程序，允许我控制播放。我将Spotify AppleScript API与Objective-C中的Scripting Bridge结合使用。我想问的第一件事是，Scripting API是否支持Key Value Observing？因为当我添加观察者时，我没有从API获得任何通知，当我尝试从Scripting API手动获取数据时，我总是得到nil值，为什么？我有以下代码：

    -(id)init
    {
        self=[super init];
        if(self)
        {
            spotify=[SBApplication applicationWithBundleIdentifier:@"com.spotify.client"];
            //Not sure if KVO is implemented,so I use this to get data from the API
            timer=[NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(observeValueForKeyPath) userInfo:nil repeats:YES];
            if([self isSpotifyRunning])
            {
                //Useless?
                [spotify addObserver:self forKeyPath:@"currentTrack" options:NSKeyValueObservingOptionNew context:nil];
                [spotify addObserver:self forKeyPath:@"playerPosition" options:NSKeyValueObservingOptionNew context:nil];
                [spotify addObserver:self forKeyPath:@"playerState" options:NSKeyValueObservingOptionNew context:nil];
                [self.playBackSlider setTarget:self];
                [self.playBackSlider setAction:@selector(sliderDidMove:)];
                if(spotify.playerState==SpotifyEPlSPaused||spotify.playerState==SpotifyEPlSStopped)
                {
                    [self.playButton setStringValue:@"Play"];
                }
                else
                {
                    [self.playButton setStringValue:@"Stop"];
                }
            }

        }
        return self;
    }
    -(void)observeValueForKeyPath
    {
            [self.titleTextField setStringValue:spotify.currentTrack.name];
            [self.artistTextField setStringValue:spotify.currentTrack.artist];
            [self.currentPlayBackPositionTextField setStringValue:[self formatTime:spotify.playerPosition]];
            [self.remainingTimeTextField setStringValue:[self formatTime:spotify.currentTrack.duration]];
            [self.playBackSlider setMaxValue:spotify.currentTrack.duration];
            [self.playBackSlider setDoubleValue:spotify.playerPosition];
            [self.playBackSlider setDoubleValue:spotify.playerPosition];
            [self.currentPlayBackPositionTextField setStringValue:[self formatTime:spotify.playerPosition]];
        if(spotify.playerState==SpotifyEPlSPaused||spotify.playerState==SpotifyEPlSStopped)
        {
            [self.playButton setStringValue:@"Play"];
        }
        else
        {
            [self.playButton setStringValue:@"Stop"];
        }
    }
-(void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary<NSString *,id> *)change context:(void *)context
{
    if([keyPath isEqualToString:@"currentTrack"])
    {
        [self.titleTextField setStringValue:spotify.currentTrack.name];
        [self.artistTextField setStringValue:spotify.currentTrack.artist];
        [self.currentPlayBackPositionTextField setStringValue:[self formatTime:spotify.playerPosition]];
        [self.remainingTimeTextField setStringValue:[self formatTime:spotify.currentTrack.duration]];
        [self.playBackSlider setMaxValue:spotify.currentTrack.duration];
        [self.playBackSlider setDoubleValue:spotify.playerPosition];
    }
    else if([keyPath isEqualToString:@"playerPosition"])
    {
        [self.playBackSlider setDoubleValue:spotify.playerPosition];
        [self.currentPlayBackPositionTextField setStringValue:[self formatTime:spotify.playerPosition]];
    }
    else if([keyPath isEqualToString:@"playerState"])
    {
        if(spotify.playerState==SpotifyEPlSPaused||spotify.playerState==SpotifyEPlSStopped)
        {
            [self.playButton setStringValue:@"Stop"];
        }
        else
        {
           [self.playButton setStringValue:@"Play"];
        }
    }
}

编辑：我为SBApplication对象设置了委托，我收到以下错误：

错误域= NSOSStatusErrorDomain代码= -600“procNotFound：no 具有指定描述符的合格进程的UserInfo = {ErrorNumber = -600}

究竟是什么意思？ Spotify在创建SBApplication时启动，那么为什么SBApplication告诉我它没有找到进程？我还看了一下Spotify Bundle中的Info.plist，它是可编写脚本的，为什么它不起作用？

提前感谢您的帮助！

Answer 1

任何应用程序的AppleScript脚本字典 - 您称之为AppleScript API - 并不支持KVO。

关于在Cocoa应用程序中使用脚本字典忘记ScriptingBridge。

AppleScriptObjC（在10.6 Snow Leopard中引入）提供了一种更轻松的与AppleScript交互的方式。您甚至可以使用AppleScript在同一文件中使用AppleScript和类似Objective-C的术语在AppleScriptObjC中完全编写Cocoa应用程序。

脚本桥不起作用（KVO，零值）

1 个答案: