change size of a rectangle during runtime in objective C - ios

Question

Hi guys i have a quick question
I am using xcode to build an app and I want to animate the size of a custom rectangle during runtime.
I have a UIView class where i create custom rectangles and draw them on the screen of the ViewController. The problem is, whenever i start the app, it just create all the rectangles and then shows the screen.
What i want it to do is to show the screen and then animate the rectangles (like a "growing-animation")
This is how i create the rectangles in the UIView class
-(void)newRectWithX:(int) x height:(int) height{
_rdmRed = arc4random_uniform(100);
_rdmRed /= 100;
_rdmGreen = arc4random_uniform(100);
_rdmGreen /= 100;
_rdmBlue= arc4random_uniform(100);
_rdmBlue /= 100;
_color = [UIColor colorWithRed:_rdmRed green:_rdmGreen blue:_rdmBlue alpha:0.6];
[UIView animateWithDuration:50 delay:10 options:UIViewAnimationOptionShowHideTransitionViews
animations:^{
CGContextRef context = UIGraphicsGetCurrentContext();
CGRect rectangle = CGRectMake(x,0,4,height);
CGContextAddRect(context, rectangle);
CGContextSetFillColorWithColor(context, [_color CGColor]);
CGContextFillRect(context, rectangle);
}
completion:nil];
}
I didn't do anything in the ViewController class yet.

Answer 1

+ animateWithDuration:delay:options:animations:completion:
Animate changes to one or more views using the specified duration, delay, options, and completion handler.
To be able to use that method you will need to animate a view. Here is a chuck of code that will allow you to use that method and CoreGraphics.
#implementation View
{
UIView * view;
}
- (void)runAnimation {
[NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:#selector(setNeedsDisplay) userInfo:nil repeats:YES];
view = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 10, 10)];
[UIView animateWithDuration:1 delay:0 options:UIViewAnimationOptionShowHideTransitionViews animations:^{
view.frame = CGRectMake(0, 0, 20, 20);
} completion:nil];
}
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect {
// Drawing code
CGContextRef context = UIGraphicsGetCurrentContext();
CGRect rectangle = ((UIView *)[view.layer presentationLayer]).frame;
CGContextAddRect(context, rectangle);
CGContextSetFillColorWithColor(context, [UIColor cyanColor].CGColor);
CGContextFillRect(context, rectangle);
}
#end

Answer 2

I have this to move a rectangle, maybe can help you
if(destination.origin.x > 0){
destination.origin.x = 0;
[self.navigationController.view.superview bringSubviewToFront:self.navigationController.view];
}else{
destination.origin.x += _sideMenu.view.frame.size.width;
}
[UIView animateWithDuration:0.2 animations:^{
self.view.frame = destination;
}completion:^(BOOL finished) {
if(finished){
if (destination.origin.x > 0) {
[self.navigationController.view.superview bringSubviewToFront:_sideMenu.view];
} else {
}
}
}];
change the destination.origin to destination.size, like this
CGRect destination = self.view.frame;
if(destination.size.height > 10){
destination.size.height = 10;
[self.navigationController.view.superview bringSubviewToFront:self.navigationController.view];
}else{
destination.size.height += 10;
}
[UIView animateWithDuration:0.2 animations:^{
self.view.frame = destination;
}completion:^(BOOL finished) {
if(finished){
if (destination.size.height > 10) {
[self.navigationController.view.superview bringSubviewToFront:_sideMenu.view];
} else {
}
}
}];