My Duration is String. duration = @"00:06:29" how to get the float time value to move my uislider bar : how to get the float time value for my json data. below code i got my duration in string then how can i convert into the float value to pass my uislider bar total length of the audio. please help me to move my uislider bar. 

    //Json Data
    {
            duration = "00:03:45";
            id = 8;
    }

//Audio player sider bar function

     if(audioController.playbackState == MPMusicPlaybackStatePlaying){
        
        
        if (isSelected == YES) {
            currentAutio = audioList[selectedAudio];
        } else {
            currentAutio = audioList[0];
        }
        NSNumberFormatter *numberFormatter = [[NSNumberFormatter alloc] init];
        numberFormatter.numberStyle = NSNumberFormatterDecimalStyle;
        
        float value = [numberFormatter numberFromString:currentAutio.duration].floatValue;
        
        float currentPlaybackTime = [audioController currentPlaybackTime];
        float TotalLength = value;
        
        float remainingPlaybackTime = TotalLength - currentPlaybackTime;
        
        float sliderPosition = (currentPlaybackTime *100) / TotalLength;
        
        NSLog(@"current playbacktime %f",currentPlaybackTime);
        NSLog(@"TotalLength %f",TotalLength);
        NSLog(@"remainingPlaybackTime %f",remainingPlaybackTime);
        NSLog(@"sliderPosition %f",sliderPosition);
        
        //Update slider
        [progressSlider setValue:sliderPosition];
        
        //Update labels
        NSDate* d1 = [NSDate dateWithTimeIntervalSince1970:currentPlaybackTime];
        NSDate* d2 = [NSDate dateWithTimeIntervalSince1970:remainingPlaybackTime];
        
        NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
        [dateFormatter setDateFormat:@"mm:ss"];
        
        NSString *currentTime = [dateFormatter stringFromDate:d1];
        NSString *ramainingTime = [dateFormatter stringFromDate:d2];
        
        [trackCurrentPlaybackTimeLabel setText:currentTime];
        [trackLengthLabel setText:[NSString stringWithFormat:@"-%@",ramainingTime]];
        
    }



out put: Value = 0.00000