Loop the code in #implementation section - objective-c

Question

I have written the program, which chooses a random element from the array.
Once I press the button "Start", how do I loop that code?
I would like, that once a button "Start" is pressed, a new element from the array is chosen and written in the text field every 5 seconds.... Thanks for the answer.
#implementation MARandom
- (IBAction)Start:(id)sender {
NSArray *tones;
tones = [NSArray arrayWithObjects: #"F#0", #"Gb0", #"G0", #"G#0",#"Ab0",#"A0",#"A#0",#"Bb0",#"B0",
#"C1",#"C#1",#"Db1",#"D1",#"D#1",#"Eb1",#"E1",#"F1",#"F#1",#"Gb1",#"G1",#"G#1",#"Ab1",#"A1",#"A#1",#"Bb1",#"B1",
#"C2",#"C#2",#"Db2",#"D2",#"D#2",#"Eb2",#"E2",#"F2",#"F#2",#"Gb2",#"G2",#"G#2",#"Ab2",#"A2",#"A#2",#"Bb2",#"B2",
#"C3",#"C#3",#"Db3",#"D3",#"D#3",#"Eb3",nil];
i= (arc4random() % 48);
NSString *Tone;
Tone = [tones objectAtIndex: i];
[TextField setStringValue:(NSString *)Tone];
}

Answer 1

Please try this:
- (IBAction)Start:(id)sender {
[NSTimer scheduledTimerWithTimeInterval:5.0
target:self
selector:#selector(updateTextFieldWithRandomNumber)
userInfo:nil
repeats:YES];
}
-(void)updateTextFieldWithRandomNumber{
NSArray *tones;
tones = [NSArray arrayWithObjects: #"F#0", #"Gb0", #"G0", #"G#0",#"Ab0",#"A0",#"A#0",#"Bb0",#"B0",
#"C1",#"C#1",#"Db1",#"D1",#"D#1",#"Eb1",#"E1",#"F1",#"F#1",#"Gb1",#"G1",#"G#1",#"Ab1",#"A1",#"A#1",#"Bb1",#"B1",
#"C2",#"C#2",#"Db2",#"D2",#"D#2",#"Eb2",#"E2",#"F2",#"F#2",#"Gb2",#"G2",#"G#2",#"Ab2",#"A2",#"A#2",#"Bb2",#"B2",
#"C3",#"C#3",#"Db3",#"D3",#"D#3",#"Eb3",nil];
i= (arc4random() % 48);
NSString *Tone;
Tone = [tones objectAtIndex: i];
[TextField setStringValue:(NSString *)Tone];
}
and also consider preparing the array at one place rather than the code that will be repeatedly called, perhaps at viewDidLoad.
Note: untested code, but should work.