Adding a NSTimer to a button - iphone

Question

I have searched all over the web with no luck of making this project work with a timer, I end up with a crashed app every time when using the timer.
For testing and learning purposes I build little simple apps. It is a button that sends a rocket from the bottom of the screen and disappears off screen, along with a rocket sound effect.
I am wanting to add a Timer to the button so that when the button is held down the rocket will launch, reset, and launch over and over until I release the button. I think my only hope now is to paste code from my .h & .m files and hopefully someone can tell me what I need to do and where the proper code needs to be added for this project.
Thank you so much for the help, it is greatly appreciated.
.H FILE:
// MVViewController.h
#import <UIKit/UIKit.h>
#import <AVFoundation/AVFoundation.h>
#interface MVViewController : UIViewController
#property (strong, nonatomic) IBOutlet UIImageView *moveMe2;
//New action to repeat launch (Touch Down)
- (IBAction)rocketRepeat:(id)sender;
//New action to stop launch (Touch Up Inside)
- (IBAction)rocketStop:(id)sender;
//This is the original launch button (Touch Down)
- (IBAction)yourRocketButton:(id)sender;
#end
.M FILE
// MVViewController.m
#import "MVViewController.h"
#interface MVViewController ()
#end
#implementation MVViewController {
AVAudioPlayer *audioPlayer;
}
#synthesize moveMe2;
- (void)viewDidLoad
{
[super viewDidLoad];
}
- (void)viewDidUnload
{
[self setMoveMe2:nil];
[super viewDidUnload];
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
return ((interfaceOrientation == UIInterfaceOrientationPortrait) || (interfaceOrientation == UIInterfaceOrientationPortraitUpsideDown));
}
- (IBAction)rocketRepeat:(id)sender
//Getting error "Use of undeclared identifier 'yourRocketButton'
{
[yourRocketButton addTarget:self action:#selector(rocketRepeat:) forControlEvents:UIControlEventTouchDown];
}
- (IBAction)rocketStop:(id)sender
//Getting error "Use of undeclared identifier 'yourRocketButton'
{
[yourRocketButton addTarget:self action:#selector(rocketStop:) forControlEvents:UIControlEventTouchUpInside];
}
- (IBAction)yourRocketButton:(id)sender {
moveMe2.center = CGPointMake(100.0f, 408.0f);
[UIView animateWithDuration:2.0 animations:^{moveMe2.center = CGPointMake(100, -55);}];
}
#end
########
EDIT *This is what finally worked*
// RKViewController.m
#import "RKViewController.h"
#interface RKViewController ()
#end
#implementation RKViewController
#synthesize RocketMove;
#synthesize Launch;
- (void)viewDidLoad
{
[super viewDidLoad];
}
- (void)viewDidUnload
{
[self setRocketMove:nil];
[self setLaunch:nil];
[super viewDidUnload];
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
return ((interfaceOrientation == UIInterfaceOrientationPortrait) || (interfaceOrientation == UIInterfaceOrientationPortraitUpsideDown));
}
- (IBAction)rocketRepeat:(id)sender {
[self performSelector:#selector(rocketRepeat:) withObject:self afterDelay:1.0];
RocketMove.center = CGPointMake(100.0f, 408.0f);
[UIView animateWithDuration:1.0 animations:^{RocketMove.center = CGPointMake(100, -55);}];
}
- (IBAction)rocketStop:(id)sender {
[NSObject cancelPreviousPerformRequestsWithTarget:self];
}
#end
// RKViewController.h
#import <UIKit/UIKit.h>
#interface RKViewController : UIViewController
#property (strong, nonatomic) IBOutlet UIImageView *RocketMove;
#property (strong, nonatomic) IBOutlet UIButton *Launch;
- (IBAction)rocketRepeat:(id)sender;
- (IBAction)rocketStop:(id)sender;
#end

Answer 1

You have to use UIControlEvent for this purpose.
1. You need two separate IBActions for each purpose, say one for holding down the button, one after the button is released.
2. For holding down the button you need to use UIControlEventTouchDown. So have a rocketRepeat action where you keep calling the rocket action using the NSTimer with regular intervals and use:
[yourRocketButton addTarget:self action:#selector(rocketRepeat:) forControlEvents:UIControlEventTouchDown];
3. Then use another action with UIControlEventTouchUpInside where you will invalidate the NSTimer so the rocket stops. Call that action rocketStop or something and use:
[yourRocketButton addTarget:self action:#selector(rocketStop:) forControlEvents:UIControlEventTouchUpInside];
---EDIT---
Action 1 :
- (IBAction)rocketRepeat:(id)sender
{
//code for starting rocker, timer action
}
Action 2:
- (IBAction)rocketStop:(id)sender
{
//Code for stopping rocket
}
yourButton is not an action, its a UIButton. I hope you have created a button in the IB, drag and dropped the button. And in viewDidLoad you write these 2 lines of code :
Instead of yourButton you write the name of the button you have dragged dropped from the IB. I hope you know how to add a button from the interface builder and connect it.
- (void)viewDidLoad
{
[yourRocketButton addTarget:self action:#selector(rocketRepeat:) forControlEvents:UIControlEventTouchDown]; //For touch down button action
[yourRocketButton addTarget:self action:#selector(rocketStop:) forControlEvents:UIControlEventTouchUpInside]; //When button is let go.
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}

Answer 2

If you want that the rockets are autolaunched once you press the button, you should add the following code to your rocketLaunch: method. If you want them to start appearing from the beginning, call this from your viewDidLoad method.
- (void)launchRocketsTimer
{
[self.timer invalidate]; //you have to create a NSTimer property to your view controller
self.timer = [NSTimer scheduledTimerWithTimeInterval:2.5 target:self selector:#selector(scheduledRocketLaunch:) userInfo:nil repeats:YES];
}
- (void)scheduledRocketLaunch:(NSTimer *)t
{
moveme2.center = _bottom_point_; //set it where you would like it to start
[UIView animateWithDuration:2.0 animations:^{moveMe2.center = CGPointMake(100, -55);}];
}
Remember to release your timer in dealloc.
Oh, and one more thing:
You have a memory leak on your rocketsound: method when you allocate your AVAudioPlayer. You may replace the code with this one:
- (IBAction)rocketsound:(id)sender
{
NSURL *url = [NSURL fileURLWithPath: [NSString stringWithFormat:#"%#/rocketlaunch.mp3", [[NSBundle mainBundle] resourcePath]]];
NSError *error;
if (self.audioPlayer == nil)
{
self.audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:url error:&error] autorelease]; //Note the use of setter property and the autorelease. (you could use your own code because the if will prevent the leak in this case).
}
audioPlayer.numberOfLoops = 0;
if (audioPlayer == nil)
NSLog(#"%#", [error description]);
else
[audioPlayer play];
}