Issue with Tempo Slider - Drum Sequencer Obj - C - ios

Question

I am creating a simple drum machine. This function controls the time between each sample that is played (thus controlling the tempo of the drum machine). I need to control the tempo with a slider, so I'm hoping to be able to control the 'time duration until next step' value with this if possible. However, when I have tried to do this, it tells me "time is part of NSDate"
-(void)run
{
#autoreleasepool
{
// get current time
NSDate* time = [NSDate date];
// keeping going around the while loop if the sequencer is running
while (self.running)
{
// sleep until the next step is due
[NSThread sleepUntilDate:time];
// update step
int step = self.step + 1;
// wrap around if we reached NUMSTEPS
if (step >= NUMSTEPS)
step = 0;
// store
self.step = step;
// time duration until next step
time = [time dateByAddingTimeInterval:0.5];
}
// exit thread
[NSThread exit];
}
}
This tells me NSTimeInterval is an incompatable type
// time duration until next step
time = [time dateByAddingTimeInterval: self.tempoControls];
Here is where the slider is declared
.m
- (IBAction)sliderMoved:(UISlider *)sender
{
AppDelegate* app = [[UIApplication sharedApplication] delegate];
if (sender == self.tempoSlider)
{
PAEControl* tempoControl = app.tempoControls[app.editIndex];
tempoControl.value = self.tempoSlider.value;
}
}
.h
#interface DetailController : UIViewController
#property (weak, nonatomic) IBOutlet UISlider *tempoSlider;
- (IBAction)sliderMoved:(UISlider *)sender;
Any help would me much appriciated, thanks in advance.

Answer 1

It looks like self.tempoControls is an array of PAEControl objects. The method named dateByAddingTimeInterval: needs an argument of type NSTimeInterval (aka double). It looks like you're trying to pass in this array instead.
Try changing this line -
time = [time dateByAddingTimeInterval: self.tempoControls];
To maybe this -
PAEControl* tempoControl = self.tempoControls[self.editIndex];
time = [time dateByAddingTimeInterval: (NSTimeInterval)tempoControl.value];
On another note, if this is all running on the main thread, be aware that you are blocking it and the UI will become very unresponsive.