Moving object back and forth on screen? - ios

Question

I'm just starting out with my first Xcode project and I'm trying to create a square that moves back and forth on the screen using two timers, because I eventually want to make it so that the user can stop the object (which is a square) by tapping a button on the screen.
For now though, I've made the square move to the right side of the screen and move back, but unfortunately I cannot get it to stop at the other side of the screen.
My code right now is this:
- (void)viewDidLoad
{
Square.center = CGPointMake(-9, 246);
SquareTimer1 = [NSTimer scheduledTimerWithTimeInterval:0.004 target:self selector:#selector(moveSquare1)userInfo:nil repeats:YES];
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}
- (void)moveSquare1
{
Square.center = CGPointMake(Square.center.x + 0.3, Square.center.y);
if (Square.center.x > 290){
[SquareTimer1 invalidate];
SquareTimer1 = [NSTimer scheduledTimerWithTimeInterval:0.004 target:self selector:#selector(moveSquare2) userInfo:nil repeats:YES];
}
if (Square.center.x < -9){
[SquareTimer1 invalidate];
}
}
-(void) moveSquare2
{
Square.center = CGPointMake(Square.center.x - 0.3, Square.center.y);
}
The only part of my code that is not working is my second if statement. How can I fix this?

Answer 1

This should do it. Remove that second if from moveSquare1 and place it in moveSquare2
- (void)viewDidLoad
{
Square.center = CGPointMake(-9, 246);
SquareTimer1 = [NSTimer scheduledTimerWithTimeInterval:0.004 target:self selector:#selector(moveSquare1)userInfo:nil repeats:YES];
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}
- (void)moveSquare1
{
Square.center = CGPointMake(Square.center.x + 0.3, Square.center.y);
if (Square.center.x > 290){
[SquareTimer1 invalidate];
SquareTimer1 = [NSTimer scheduledTimerWithTimeInterval:0.004 target:self selector:#selector(moveSquare2) userInfo:nil repeats:YES];
}
}
-(void) moveSquare2
{
Square.center = CGPointMake(Square.center.x - 0.3, Square.center.y);
if (Square.center.x < -9){
[SquareTimer1 invalidate];
// If you want to move the Square back in the right side. Otherwise, comment this below line.
SquareTimer1 = [NSTimer scheduledTimerWithTimeInterval:0.004 target:self selector:#selector(moveSquare1) userInfo:nil repeats:YES];
}
}
Let me know if you have any doubts.