Question

我很喜欢编程我使用MPMusicPlayerController在i-phone中制作了一个音乐播放器，我能够实现这一点，但我在播放时仍然无法擦洗音频文件。我已经使用OBSLIDER来实现这一点。一切正常，但它不像Apple Default Player那么流畅.Below是我用过的代码。请帮帮我。

-(IBAction)sliderChanged:(id)sender
{
    //player is object of MPMusicPlayerController
    //total seconds is total length of song that is playing in player
    if(self.slider.value<totalseconds)
    {
        [playbackTimer invalidate];
       [self.player setCurrentPlaybackTime:slider.value];
        NSNumberFormatter *percentFormatter = [[NSNumberFormatter alloc] init];
        [percentFormatter setNumberStyle:NSNumberFormatterPercentStyle];        
        self.labelScrubbing.text = [NSString stringWithFormat:@"Scrubbing speed: %@",
                                    [percentFormatter stringFromNumber:[NSNumber numberWithFloat:self.slider.scrubbingSpeed]]];
       //to update the time when slider moves
        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_LOW, 0), ^{
            float totalDuration=slider.value;
            float mins = floor(totalDuration/60);
            float secs = round(totalDuration - mins * 60);
            int roundedSecs = lroundf(secs);
            int roundedMins = lroundf(mins);

            dispatch_sync(dispatch_get_main_queue(), ^{
                NSString *timeInfoString = [[NSString alloc]
                                            initWithFormat:@"%0d.%02d",
                                            roundedMins, roundedSecs];
                currrentDurationSong.text=timeInfoString;
  });

        });

        playbackTimer = [NSTimer scheduledTimerWithTimeInterval:1.0
                                                         target:self
                                                       selector:@selector(updateTime)
                                                       userInfo:nil
                                                        repeats:YES];

    }
    else if(self.slider.value>=totalseconds){

    }

}

我使用计时器来更新剩余的时间，这是

的代码

-(void)updateTime
{

    NSTimeInterval currentProgress = self.player.currentPlaybackTime;
    self.slider.value = currentProgress;
    NSNumberFormatter *percentFormatter = [[NSNumberFormatter alloc] init];
    [percentFormatter setNumberStyle:NSNumberFormatterPercentStyle];
    self.labelScrubbing.text = [NSString stringWithFormat:@"Scrubbing speed: %@",
                                [percentFormatter stringFromNumber:[NSNumber numberWithFloat:self.slider.scrubbingSpeed]]];
    MPMediaItem *nowPlayingMediaItem = [[MPMusicPlayerController iPodMusicPlayer] nowPlayingItem];
    NSString* title = [nowPlayingMediaItem valueForProperty:MPMediaItemPropertyTitle] ;
    NSString* artist = [nowPlayingMediaItem valueForProperty:MPMediaItemPropertyArtist] ;
      NSString* albumname = [nowPlayingMediaItem valueForProperty:MPMediaItemPropertyAlbumTitle] ;
    NSString *duration=[nowPlayingMediaItem valueForProperty:MPMediaItemPropertyPlaybackDuration];
    float totalDuration=[duration floatValue];
    float mins = floor(totalDuration/60);
    float secs = round(totalDuration - mins * 60);
    int roundedSecs = lroundf(secs);
    int roundedMins = lroundf(mins);
    NSLog(@"%02d",roundedMins);


    NSString* _albumString = [[NSString alloc]initWithFormat:@"%@",(albumname.length>0 ? albumname : @"Unknown") ];
    NSString* _artistString = [[NSString alloc]initWithFormat:@"%@",(artist.length>0 ? artist : @"Unknown") ];

    NSString *timeInfoString = [[NSString alloc]
                                initWithFormat:@"%0d.%02d",
                                roundedMins, roundedSecs];
    totalDurationSong.text=[NSString stringWithFormat:@"%@",timeInfoString];
    titleOfSong.text=title;
    ArtistOfSong.text=_artistString;
    albumNameofSong.text=_albumString;
    float min = floor(currentProgress/60);
    float sec = round(currentProgress - min * 60);
    int roundedSec = lroundf(sec);
    int roundedMin = lroundf(min);
    NSString *timeInfoStrings = [[NSString alloc]
                                 initWithFormat:@"%0d.%02d",
                                 roundedMin, roundedSec];
    currrentDurationSong.text=[NSString stringWithFormat:@"%@",timeInfoStrings];

    if(min+sec==totalseconds){

        [playbackTimer invalidate];
    }


}

Answer 1

我一直在努力解决同样的问题。问题出在currentPlaybackTime上。 currentPlaybackTime仅限于每秒发送当前时间数据。因此，无论定时器如何快速循环，它都只会每秒更新滑块。但是，由于您的计时器设置为1秒，它可能会触发currentPlaybackTime的偏移（导致一些口吃）。你可能希望加快这样的时间：

playbackTimer = [NSTimer scheduledTimerWithTimeInterval:0.1
                                                         target:self
                                                       selector:@selector(updateTime)
                                                       userInfo:nil
                                                        repeats:YES];

UISlider在iphone中的MPMusicPlayerController中无法顺利运行

1 个答案: