I've always worked with Flash, and it's pretty easy to change the alpha values between one frame and another. Is there a way to do this in xcode 4? I'm animating a logo and I need the first png to disappear while the second one starts appearing. tnx!
Alternatively to esqew's method (which is available prior to iOS 4, so you should probably use it instead if you don't plan to limit your work to just iOS 4), there is also [UIView animateWithDuration:animations:], which allows you to do the animation in a block. For example:
[UIView animateWithDuration:3.0 animations:^(void) {
image1.alpha = 0;
image2.alpha = 1;
}];
Fairly simple, but again, this is available only on iOS 4, so keep that in mind.
Other solution, fade in and fade out:
//Disappear
[UIView animateWithDuration:1.0 animations:^(void) {
SplashImage.alpha = 1;
SplashImage.alpha = 0;
}
completion:^(BOOL finished){
//Appear
[UIView animateWithDuration:1.0 animations:^(void) {
[SplashImage setImage:[UIImage imageNamed:sImageName]];
SplashImage.alpha = 0;
SplashImage.alpha = 1;
}];
}];
This is pretty simple actually. Place the following code where you want the animation to occur:
[UIView beginAnimations:NULL context:NULL];
[UIView setAnimationDuration:3.0]; // you can set this to whatever you like
/* put animations to be executed here, for example: */
[image1 setAlpha:0];
[image2 setAlpha:1];
/* end animations to be executed */
[UIView commitAnimations]; // execute the animations listed above
You can read more about these methods in this document.
If you wanna work with a structure you referred to in your comment on this question:
[UIView beginAnimations:NULL context:NULL];
[UIView setAnimationDuration:3.0]; // you can set this to whatever you like
/* put animations to be executed here, for example: */
[[introAnimation objectAtIndex:0] setAlpha:0];
[[introAnimation objectAtIndex:1] setAlpha:1];
/* end animations to be executed */
[UIView commitAnimations]; // execute the animations listed above
... should work.
Related
I have a UIButton in my code that moves steadily across the screen. Currently, when the user presses the button, the alpha changes to 0 and it just disappears. What I'd like to do is run a separate animation after the button is pressed/it has disappeared. Seems easy enough but the catch is I need to run the animation at the exact point of the button when it is pressed. And I'm drawing a blank on how to make this happen. Any help will be much appreciated! I'll post some relevant code below.
-(void)movingbuttons{
movingButton2.center = CGPointMake(x, y);
displayLink = [CADisplayLink displayLinkWithTarget:self selector:#selector(moveObject)];
[displayLink addToRunLoop:[NSRunLoop currentRunLoop] forMode:NSRunLoopCommonModes];
}
-(void)moveObject{
movingButton2.center = CGPointMake(movingButton2.center.x , movingButton2.center.y +1);
}
-(IBAction)button2:(id)sender {
[UIView beginAnimations:nil context:NULL];
[movingButton2 setAlpha:0];
[UIView commitAnimations];
}
Replace your button2 action with below code and implement the someOtherMethodWithAnimation method with the animation you want :)
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:1];
movingButton2.alpha = 0;
[UIView commitAnimations];
[self performSelector:#selector(someOtherMethodWithAnimation) withObject:nil afterDelay:1.0];
Replace your animation with:
[UIView animateWithDuration:0.25
animations:^{
self.movingbutton2.alpha = 0.0;
// modify other animatable view properties here, ex:
self.someOtherView.alpha = 1.0;
}
completion:nil];
Just a nit picking point, but is the button in your view controller's .xib file correctly hooked up to your IBOutlets and IBActions?
UPDATE:
You are not limited to modifying that one button in your method. You add what ever code you want in the animation block (see the udated axample above).
UIView animatable properties, there is an animation section there.
Another approach could be (I am just using alpha as an example):
[UIView animateWithDuration:1.0
animations:^{
self.movingButton2.alpha = 0.0;
}
completion:^{
[UIView animatateWithDuration:0.25
animations:^{
self.someOtherView.alpha = 1.0;
}
completion:nil];
}];
This will more likely guarantee the animations will hapen one after another.
I am trying to perform multiple UIView animations one after the other. However, I've heard that it's bad practice to perform multiple UIView animations one after the other, and that I should instead use Core Animation. I tried this code:
//First Animation
[UIView beginAnimations:#"animation1" context:nil];
[UIView setAnimationDuration:2];
nwView.backgroundColor = [UIColor redColor];
nwView.frame = CGRectMake(CGRectGetMidX(screenSize),
CGRectGetMinY(screenSize),
width,
height);
nwView.transform = CGAffineTransformMakeRotation(45.0f);
[UIView commitAnimations];
//Second Animation
[UIView beginAnimations:#"second animation" context:nil];
[UIView setAnimationDuration:2];
nwView.transform = CGAffineTransformMakeScale(0.5, 0.33);
nwView.backgroundColor = [UIColor purpleColor];
[UIView commitAnimations];
But it only does the second animation. I know this question is similar to UIView two animations coexisting, but it has a slightly different context.
I don't think there is anything wrong with doing 2 animations in a row using UIView blocks. Just make sure you start your second animation in the completino block of the first animation.
Without blocks (your example) it is not working as you will have to set a delegate to the animation or set a selector for setAnimationDidStopSelector. There you should start the second animation.
But again, nothing wrong in doing animations with blocks (it is the preferred way).
If you are looking to do multiple animations right after another this is not the way to do it. The code you posted with execute at almost the same time, meaning the animations would be performed at about the same time.
Instead what you should do is set the delegate for the first animation, and then do the first animation. Then when the animationDidStop method is called for the first animation, you should do the second animation. This makes sure they are one after another.
This is how you would do it, assuming you call doMyAnimations to start the animation.
-(void)doMyAnimations{
//First Animation
[UIView beginAnimations:#"animation1" context:nil];
[UIView setAnimationDuration:2];
[UIView setAnimationDelegate:self];
nwView.backgroundColor = [UIColor redColor];
nwView.frame = CGRectMake(CGRectGetMidX(screenSize),
CGRectGetMinY(screenSize),
width,
height);
nwView.transform = CGAffineTransformMakeRotation(45.0f);
[UIView commitAnimations];
}
- (void)animationWillStart:(NSString *)animationID context:(void *)context{
}
- (void)animationDidStop:(NSString *)animationID finished:(NSNumber *)finished context:(void *)context{
if([animationID isEqualToString:#"animation1"]){
//Second Animation
[UIView beginAnimations:#"second animation" context:nil];
[UIView setAnimationDuration:2];
nwView.transform = CGAffineTransformMakeScale(0.5, 0.33);
nwView.backgroundColor = [UIColor purpleColor];
[UIView commitAnimations];
}
}
Keep in mind that the nwView would have to be accessible throughout the entire class. If it isn't you can either make it an instance variable, or find another way to get access to it in the animationDidStop method.
You can use blocks for this purpose and get a very clean result.
NSMutableArray* animationBlocks = [NSMutableArray new];
typedef void(^animationBlock)(BOOL);
// getNextAnimation
// removes the first block in the queue and returns it
animationBlock (^getNextAnimation)() = ^{
animationBlock block = (animationBlock)[animationBlocks firstObject];
if (block){
[animationBlocks removeObjectAtIndex:0];
return block;
}else{
return ^(BOOL finished){};
}
};
//add a block to our queue
[animationBlocks addObject:^(BOOL finished){;
[UIView animateWithDuration:1.0 animations:^{
//...animation code...
} completion: getNextAnimation()];
}];
//add a block to our queue
[animationBlocks addObject:^(BOOL finished){;
[UIView animateWithDuration:1.0 animations:^{
//...animation code...
} completion: getNextAnimation()];
}];
//add a block to our queue
[animationBlocks addObject:^(BOOL finished){;
NSLog(#"Multi-step Animation Complete!");
}];
// execute the first block in the queue
getNextAnimation()(YES);
Taken from: http://xibxor.com/objective-c/uiview-animation-without-nested-hell/
In iOS, how can one briefly draw attention to an object on screen? Suppose, create a brief glow or cause a shadow to appear and then disappear?
For the purposes of this question, let's define "object on screen" as an instance of UIImageView.
Also, if possible provide an example of how to draw attention to a button.
Most people list code, but I'm sticking to describing some examples;
I've seen objects briefly grow and shrink back to their normal size to draw attention
Bejeweled (a Popcap game) lets diamonds briefly 'shine' (as if sunlight passed over it) to give you a subtle hint
I've seen certain applications use a hand or a fictive character point to a certain object briefly
And of course, you could always introduce a talking paperclip to tell you what's what.
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:0.1f];
yourView.transform = CGAffineTransformMakeScale(1.1, 1.1);
[UIView commitAnimations];
Or, of course the same thing with a block animations. And after the attention got away from your view you can use :
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:0.1f];
yourView.transform = CGAffineTransformIdentity;
[UIView commitAnimations];
Here is a simple hop animation...
- (void)drawAttn
{
float jumpHeight = 20.0;
CGPoint originalPoint = objectForAttn.center;
CGPoint jumpPoint = CGPointMake(objectForAttn.center.x, objectForAttn.center.y - jumpHeight);
[UIView animateWithDuration:0.20 delay:0.0 options:UIViewAnimationOptionAutoreverse animations:^{
[objectForAttn setCenter:jumpPoint];
} completion:^(BOOL finished) {
/* do other stuff after hop */
}];
}
My app QCount (free in the store, tap a "wrong" number 3 times) uses a fade animation as follows:
(note I wrote this when I was REALLY new to iOS, so there is probably a more compact way to write it)
aLabel = // a UILabel I get from somewhere
aColor = aLabel.backgroundColor;
[UIView animateWithDuration:0.2
delay: 0.0
options: UIViewAnimationOptionCurveEaseOut
animations:^{
aLabel.alpha = 0.0;
}
completion:^(BOOL finished){
// Wait .2 seconds and then fade in the view
[UIView animateWithDuration:.2
delay: 0.0
options:UIViewAnimationOptionCurveEaseIn
animations:^{
aLabel.alpha = 1.0;
}
completion:nil];
}];
There are lots of options: hopping, underlining, vibrating, blinking, rotating, scaling, endarkening around, and their combinations.
But IMO, shine effect on "slide to unlock" text is excellent.
You can check it out here:
iPhone "slide to unlock" animation
I wanted to draw attention to a label whose value had changed. This simple animation produces a nice 'I've changed' animation...
//copy the label
UILabel *newPageLabel = [[UILabel alloc] initWithFrame:_countLabel.frame];
[newPageLabel setFrame:CGRectOffset(newPageLabel.frame, 0, 0)];
newPageLabel.text = _countLabel.text;
newPageLabel.textAlignment = _countLabel.textAlignment;
newPageLabel.backgroundColor = _countLabel.backgroundColor;
newPageLabel.textColor = _countLabel.textColor;
newPageLabel.font = _countLabel.font;
//scale and fade out the copied label
[self.navigationController.toolbar addSubview:newPageLabel];
[UIView animateWithDuration:0.5
delay:0.0
options:UIViewAnimationOptionLayoutSubviews
animations:^{
newPageLabel.transform = CGAffineTransformMakeScale(2,2);
newPageLabel.alpha = 0;
}
completion:^(BOOL finished){
[newPageLabel removeFromSuperview];
}
];
I made this thing. It has no purpose other than for demonstration to myself. Essentially, I'm moving a view that I created around the screen in a loop. The problem is that it doesn't wait until it's done with one animation before starting the other, and so the view bypasses the first two and ends up at the last toastRect after the for loop is done, and it doesn't keep moving after that. How can I force the code to complete each animation before moving on to the next?
int i;
for (i=0; i < 100; i++) {
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:9];
toast.view.frame = toastRect1;
[UIView commitAnimations];
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:9];
toast.view.frame = toastRect2;
[UIView commitAnimations];
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:9];
toast.view.frame = toastRect;
[UIView commitAnimations];
NSLog(#"%d",i);
}
}
I think you need to use + (void)setAnimationDidStopSelector:(SEL)selector. Take a closer look at http://developer.apple.com/library/ios/#documentation/uikit/reference/uiview_class/uiview/uiview.html if you want.
You can use the setAnimationDidStopSelector method to chain the animations. Check the docs for details: http://developer.apple.com/library/ios/#documentation/uikit/reference/uiview_class/uiview/uiview.html%23//apple_ref/occ/clm/UIView/setAnimationDidStopSelector:
I have a small UIView and want to let it move to center of screen first, and then, zoom to full screen.
But when I begin start an animation like
[UIView beginAnimations:#"animation1" context:nil];
[UIView setAnimationDuration:0.5];
[UIView setAnimationDelegate:self];
[UIView setAnimationDidStopSelector:#selector(showDetailToFullscreen)];
self.currentDetailVC.frame = centerFrame;
[UIView commitAnimations];
And in the same controller, I have a method:showDetailToFullscreen
- (void)showDetailToFullscreen {
CGRect screenFrame = CGRectMake(0, 0, self.view.bounds.size.width, self.view.bounds.size.height);
[UIView beginAnimations:#"animation2" context:nil];
[UIView setAnimationDuration:0.5];
self.currentDetailVC.view.frame = screenFrame;
[UIView commitAnimations];
}
but when start, it still executed together.
I think the problem they are still in the same transaction. But how can I let these two animation executed one by one? Appreciate for any answer!
Try this instead of the setAnimationDidStopSelector:
[self performSelector:#selector(showDetailToFullscreen) withObject:nil afterDelay:0.5];
It's now considered much better to annimate views using the 'blocks' methods that can be found in the "Animating Views with Blocks" section in the UIView Class Reference.
In most of these methods you can specify a "completion" block of code that can be used to start off a second animation when the first animation completes. You could also call showDetailToFullscreen within this completion block.
I'd reccommend trying this method instead.
Are you targetting iOS 4 or later? If so, I recommend using the block-based animation methods instead. What you want to do is very easy:
Example from UIView docs:
[UIView animateWithDuration:0.2
animations:^{view.alpha = 0.0;}
completion:^(BOOL finished){ [view removeFromSuperview]; }];