- (void)showLabelAnimation
{
[UIView beginAnimations:#"animationID" context:nil];
[UIView setAnimationDuration:1];
//original rectangle is (0,0,100,50)
//and I want to change label to (100,100,200,100)
label.bounds = CGRectMake(100, 100, 200, 100);
label.frame = CGRectMake(100, 100, 200, 100);
[UIView commitAnimations];
}
It works well, but I just wondering why I have to set both bounds and frame of label. They seem like the same thing.
Can anyone explains this for me?
Thanks in advance.
[Edit in Nov 3rd]
Thanks for your help, but when I remove the setbounds line, it doesn't work well, the label will be large immediately but move to new position by animation. The resize animation does not show up.
That's the real thing which wonder me.
You should only have to set the frame. Bounds should update on its own.
Edit for additional help:
Labels don't scale; changing the frame of it changes where the text is placed, but the size of the text does not scale this way.
However, you can enable the UILabel's adjustsFontSizeToFitWidth property to 'yes' and then before you run the animation, set the font size to be at its largest before running it. As it scales, the font size should change to fit and achieve the effect you're looking for.
The frame is the rectangle relative to the view's parent. The bounds is the rectangle relative to itself.
The animation should work without the line
label.bounds = CGRectMake(100, 100, 200, 100);
That code is working for me
[UIView animateWithDuration:1
animations:^(void) {
self.leLabel.frame = CGRectMake(labFrame.origin.x,
labFrame.origin.y + 100.0f, labFrame.size.width + 50.0f, labFrame.size.height);
}];
For what you want to do, you should only set the frame.
If I change frame by bound in the previous code I will get a very strange behaviour.
So my guess is the reason you need to set both is because you've tested first with bound and added frame after to correct the error introduced by the setting of bound.
Related
I started studying objective-c using the iPhone and iPad apps for Absolute Beginners by Rory Lewis book but i got stuck on the 5th chapter.
I want to make a button that shrinks an image.
My problem is, that after I wrote all the code, the image shrinks to the point (0, 0) of the UIImageView (the top left), while in the video the image shrinks to its center. I've done some research and found out that CGAffineTransform uses the center of the object to make translations, rotations etc.
So why does it not work in my case?
I have the latest Xcode version and haven't done anything strange.
I hope I've been clear. Sorry for my English.
EDIT
Sorry for the code, but i wrote the question from my phone.
Anyway the incriminated part goes something like this
- (IBAction)shrink:(id)sender {
if(hasShrink == NO){
[shrinkButton setTitle:#"Grow" forState:UIControlStateNormal];
}
else if(hasShrink == YES){
[shrinkButton setTitle:#"Shrink" forState:UIControlStateNormal];
}
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:1.0];
myIcon.transform = CGAffineTransformMakeScale(.25, .25);
hasShrink = YES;
[UIView commitAnimations];
}
All the animations are correctly written and the app does work, it just shrinks to the top left. Why is the point not set to the center of the UIImageView by default like it should be?
EDIT:
I figured out it was a problem caused by AutoLayout.
Once disabled everything went smooth ;)
If you are transforming a view mangled managed by auto-layout, you may experience some strange side-effects. See this answer for more details.
The solution I ended up employing was to encapsulate the view I wanted to transform inside another view of exactly the same size. The outer view had the appropriate layout constraints applied to it while the inner view was simply centered in its container. Applying a CGAffineTransform scale transform to the inner view now centers properly.
Old question... but just in case others come looking:
The CGAffineTransform acts (rotates, scales) around an anchorPoint.
If you are sizing to 0, 0 then your anchor point is set to 0, 0. If you want it to size to a different point, such as the center of the image, you need to change the anchor point.
The anchor is part of a layer
So if you have a UIImageView called imageview, you would make a call like this to set the anchor to the center of imageview:
[imageview.layer setAnchorPoint:CGPointMake(0.5, 0.5)];
Try something like this:
CGAffineTransform t = CGAffineTransformMakeScale(0.5, 0.5);
CGPoint center = imageView.center; // or any point you want
[UIView animateWithDuration:0.5
animations:^{
imageView.transform = t;
imageView.center = center;
}
completion:^(BOOL finished) {
/* do something next */
}];
Next time show your code. It will be easier to help you.
Check this project: https://github.com/djromero/StackOverflow/archive/Q-13706255.zip
You must study how autolayout and autoresize affect your views. In the project above both are disabled to let you see how it works.
I have a UIView which contains two subviews. I would like to change the superview's frame size with an animation and have the subviews' sizes change in accordance with their autoresize masks.
[UIView beginAnimations:#"Resize" context:nil];
[UIView setAnimationDuration:1.0];
CGRect frame = self.myView.frame;
frame.size.height += 30.0;
self.myView.frame = frame;
[UIView commitAnimations];
The view self.myView is resized over 1 second as expected, but the subviews are resizing immediately. Does anyone know why this is happening and how I might make the subviews animate their resizing as well?
From my googling around, I think it might have something to with the contentMode property. Unfortunately, I'm not really clear as to what that property does. Any help would be much appreciated.
It would have been hard for someone else to give you the correct answer w/o seeing your code though I would have asked you what you are doing after [UIView commitAnimations]. Nevertheless, glad you figured it out. I suggest you use the block animations. They make this type of mistake much easier to avoid by using a completion block. Example:
[UIView animateWithDuration:1.0
animations:^{
CGRect frame = self.myView.frame;
frame.size.height += 30.0;
self.myView.frame = frame;
}
completion:^(BOOL finished){
// whatever you need to do when animations are complete
}];
OK, so I figured out the issue after reading the answer to the following question: Animating a UIView frame, subview UIScrollView doesn't always animate
I basically was doing some work after I scheduled the animation which was causing -layoutSubviews to be called on each of my subviews which automatically caused those views to be arranged at the end point of the animation. By scheduling my animation after this work was done I was able to solve my problem.
I have a UIView which I want to grow from it's center when a user touches it. The problem is that when animating it the view expands left and then moves to the right, whereas I want it to expand to the left and right, while keeping the center point the same.
This is the code I have at the moment:
[UIView animateWithDuration:1 animations:^(void) {
[view setFrame:CGRectMake(-10, 0, 320, view.frame.size.height)];
}];
I didn't think it was going to be difficult to do this, but it seems it is. Short of animating it manually with a timer I have no idea how to get it to expand from it's center.
I am not quite sure why it's working for you in a weird manner. Did you alter the anchorPoint property in any way? Otherwise it should grow from center.
Does doing
CGRect newFrame;
newFrame = CGRectInset(view.frame, -10, -30);
[UIView animateWithDuration:1 animations:^(void) {
view.frame = newFrame;
}];
also give you the same result? What about this?
[UIView animateWithDuration:1 animations:^(void) {
view.transform = CGAffineTransformScale(view.transform, 1.1, 1.1);
}];
Try the code given by #Deepak Danduprolu and also don't forgot to UnCheck the "Use AutoLayout" checkbox in the show file inspector window of the storyboard.
It works for me.
Just offset the X,Y position of the view. Lets say you're DECREASING both the width and height of the frame by 20 points: you should then ADD 10 points to both the X and Y position of the frame.
So I'm trying to animate an image stretching from a zero width to full size while fading in. The fade in comes across fine, but for whatever reason the thing appears at the full frame at the start of the animation, instead of growing as the alpha effect happens. My code is as follows:
[UIView beginAnimations:#"FadeButtons" context:nil];
[UIView setAnimationDuration:.9];
[UIView setAnimationDelay:0.300];
batteryLife.alpha = 1;
batteryLife.frame = CGRectMake(40, 71, 240, 128);
[UIView commitAnimations];
Any advice on changing a frame in an animated fashion? I don't want to scale the entire image, I want to "unveil" it. Thanks.
Perhaps the frame is already that size before beginAnimations? Try setting the frame immediately before beginAnimations to the smaller size, like batteryLife.frame = CGRectMake(40, 71, 0, 128);
I have a UIView called goalBar which is being animated by increasing the size of the frame according to a float value called destination:
CGRect goalBarRect = CGRectMake(0, 0, destination, 29);
[UIView beginAnimations:#"goal" context:nil];
[UIView setAnimationCurve:UIViewAnimationCurveEaseIn];
[UIView setAnimationDuration:2.0f];
goalBar.frame = goalBarRect;
[UIView commitAnimations];
The animation works perfectly and the rectangular view increases its width over the course of the animation (from 0 to the value for destination).
However, I wish to be able to extract the values for the frame of the UIView being animated (i.e. goalBar) as the animation takes place. By that I mean that I wish to place the value of the width for the animated frame in a separate UILabel so that the user sees a counter that provides the width of the UIView as it's being animated.
Any help on how to do the above would be gratefully received.
How about observing the frame property of the view. So that you get callbacks when it changes.
See Key-Value Observing.
I've looked into this and it seems that it is not possible to get updates on the state of the components being animated during the UIView animation process.