ios animation one by one - ios

Question

I have some views and I want to display them one by one . I can't find how to do this . Instead , if I use the following code , all the views appear at once .
NSTimer *timer1 = [NSTimer scheduledTimerWithTimeInterval:2 target:self selector:#selector(showStar2) userInfo:nil repeats:NO];
NSTimer *timer2 = [NSTimer scheduledTimerWithTimeInterval:2 target:self selector:#selector(showStar3) userInfo:nil repeats:NO];
NSTimer *timer3 = [NSTimer scheduledTimerWithTimeInterval:2 target:self selector:#selector(showStar4) userInfo:nil repeats:NO];
NSTimer *timer4 = [NSTimer scheduledTimerWithTimeInterval:2 target:self selector:#selector(showStar5) userInfo:nil repeats:NO];
[timer1 fire];
[timer2 fire];
[timer3 fire];
[timer4 fire];
-(void)showStar2
{
[UIView beginAnimations:#"anim1" context:NULL];
[UIView setAnimationDuration:0.5];
[stars[1] setAlpha:1];
[UIView commitAnimations];
}
All the showStar functions are identical except the lines
[UIView beginAnimations:#"anim1" context:NULL];
[stars[1] setAlpha:1];
which have different arguments . stars is an array of UIImageView's.
Any suggestion is welcome .

Answer 1

Actually you are firing all the timers exactly after 2 seconds. Change the timeInterval for different timers.
Instead you can use a single NSTimer that will fire repeatedly.
Declare NSUInteger count; in .h file.
Start a NSTimer as follows:
[NSTimer scheduledTimerWithTimeInterval:2 target:self selector:#selector(showStar:) userInfo:nil repeats:YES];
And your showStar method should be as follows:
-(void)showStar:(NSTimer*)timer
{
if( count > 0 )
{
[stars[count-1] setAlpha:0];
}
[UIView beginAnimations:#"anim1" context:NULL];
[UIView setAnimationDuration:0.5];
[stars[count] setAlpha:1];
[UIView commitAnimations];
count++;
if( count == 4 )
{
[timer invalidate];
count = 0;
}
}
The following code has been added.
if( count > 0 )
{
[stars[count-1] setAlpha:0];
}

Answer 2

All your timers are using the same time delay, so that's what the all appear at once. Also, don't call fire on the timers, they fire automatically. Calling fire probably makes them fire right away.
Incidentally, you don't need to use timers to trigger the animations, you can just add this to your animations:
[UIView setAnimationDelay:x];
And use a different x for each view.

Answer 3

I would do something like this
- (void)firstAnimation{
[UIView animateWithDuration:2.0f animations:^{
//first animation
} completion:^(BOOL finished){
[self secondAnimation];
}];
}
probably with recursion and a flag for current animation would be cleaner though

Answer 4

In my opinion your implementation is wrong.
Better to place a UImageView on your UIView.
Next create an NSArray of images and load then onto the imageView.
arrAnimations = [[NSArray alloc] initWithObjects:[UIImage imageNamed:#"image1.png],.....nil];
then call
imageView.animationImages= arrAnimations;
imageView.animationDuration=2;
[imageView startAnimating];