I'm trying to add a continuous animation onto my UITableViewCell-Subclass.
It's a rather easy one with an Image fading in and out (fading between 0.4 alpha and 1.0),
what I've tried so far ist the following:
-(void)animateRecordingIndicator{
[UIView beginAnimations:#"RecordingIndicatorAnimation" context:nil];
[UIView setAnimationDuration:0.3];
[UIView setAnimationDelegate:self];
[UIView setAnimationDidStopSelector:#selector(animationFinished)];
if (animatedImageView.alpha == 0.4)
animatedImageView.alpha = 1.0;
else
animatedImageView.alpha = 0.4;
[UIView commitAnimations];
}
the code within animationFinished is as follows:
-(void)animationFinished{
if (doShowAnimation) {
[self performSelectorOnMainThread:#selector(animateRecordingIndicator) withObject:nil waitUntilDone:YES];
}
}
what I expect should be clear by now, but what I get is simply a crash with Xcode loading Stackframes more or less eternally :)
According to the UIView class reference, you are now discouraged from using the commitAnimations method. Instead use the following:
animateWithDuration:delay:options:animations:completion:
I imagine the infinite recursion you are encountering is related to Apple's reasons for making that recommendation.
Related
I have a animation view. When the animation is finished I would like to show a new view by setting its hidden to false.
I set the hidden to false after the animation block code, but it seems like the animation is being done on a separate thread. The view gets unhidden while the animation block is still playing
// start animation block
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:2];
[UIView setAnimationCurve:UIViewAnimationCurveEaseOut ];
[UIView setAnimationTransition:UIViewAnimationTransitionFlipFromLeft forView:mCards[r] cache:YES];
// mCards[0].image = [UIImage imageNamed:#"card.png"]; //begin
int id=TarretWheel[r];
mCards[r].image = gCardImages[id]; //end
// Start animtion
[UIView commitAnimations];
// show view
mBackground.hidden=false;
You can (and preferably should, actually), be using the newer block-based animation methods on UIView. Check out the following (it has a completion block which is just what you need):
[UIView animateWithDuration:0.5 animations:^{
} completion:^(BOOL finished) {
}];
Edit:
There are other variants with options that you may want in your case.
Also, clarification on why you 'should' be using the block-based methods; from the docs (for beginAnimations:context:):
Use of this method is discouraged in iOS 4.0 and later. You should use
the block-based animation methods to specify your animations instead.
My answer is same as Joe but I would recommend using a different API which allows you with configure block.
[UIView animateWithDuration:2
delay:0.0
options:UIViewAnimationOptionTransitionFlipFromLeft|UIViewAnimationOptionCurveEaseOut |
animations:^{
// mCards[0].image = [UIImage imageNamed:#"card.png"]; //begin
int id=TarretWheel[r];
mCards[r].image = gCardImages[id]; //end
}
completion:^(BOOL finished){
mBackground.hidden=false;
}
];
Whilst playing around with UIView animation, I came across a situation where I think some refactoring is needed:
The following views whose opacity are initially set to 0.0f.
Ex:
[UIView animateWithDuration:1.0f
animations:^
{
firstView.layer.opacity = 1.0f;
}
completion:^(BOOL finished)
{
[UIView animateWithDuration:1.0f
animations:^
{
secondView.layer.opacity = 1.0f;
firstView.layer.opacity = 0.0f;
}
completion:^(BOOL finished)
{
[UIView animateWithDuration:1.0f
animations:^
{
thirdView.layer.opacity = 1.0f;
secondView.layer.opacity = 0.0f;
}
completion:^(BOOL finished)
{
thirdView.layer.opacity = 0.0f;
}];
}];
}];
All 3 views are just subclass of UIView's, which are added as subviews of the main view.
This simply animates the opacity of the first view to 1.0f and then that of the second view, and then that of the third view.
Simple. Nothing special here.
My Question is:
What if I had more views, let say 100, that I wanted to perform the same action (same sequence of animation), this block of code would expand and expand.
So for the sake of refactoring and being adhered to good practice of writing code, I thought may be this could be done with less code via the use of a method and perhaps a loop.
Could you enlighten me on this in regards to refactoring; in addition, would dispatch_apply be useful here along with the refactoring process if a loop is needed?
If you wanted to animate 100 images, you would probably want to use 2 views and load alternating images into each one. I recently created a sample app on github that does exactly that:
Animating UIImages with cross-fade opacity changing
The standard UIView animateWithDuration: block works great for animations that have require a single animation effect, i.e. resize and/or move.
Is there a way to make the animation progressive, such that the animation starts slow, and gains speed as it progresses?
I could try nested animateWithDuration: blocks, placing subsequent blocks in the completion handler, but that way the animation is a little 'ragged'. I wish to make the animation smooth.
One idea that comes to mind is that I create a recursive function as follows:
- (void) animateToYOrigin:(CGFloat)yOrigin{
if (myView.frame.origin.y < 1){
[UIView animateWithDuration:0.1
animations:^{
CGRect rect = myView.frame;
rect.origin.y = yOrigin;
myView.frame = rect;
} completion:^(BOOL finished) {
[self animateToYOrigin:yOrigin /2];
}];
}
}
I am looking for a refined solution.
You can use
[UIView animateWithDuration:time
delay:delay
options:OPTION_HERE
animations:anims
completion:completion]
method and pass UIViewAnimationOptions where it says OPTION_HERE. You can use basic ease in/out options by default. If you need more options you can check out this git repo. In MTTimingFuncations.h/c you can find multiple options you can pass.
I have this code:
when image change alpha from 0.00 to 1.00 it is imediately and not in 3 seconds, why?
- (void) startAnimation{
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:3];
[successView setAlpha:1.00];
[UIView commitAnimations];
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:3];
[successView setAlpha:0.00];
[UIView commitAnimations];}
Both animations are run in the same run cycle (that's how UIView animations work—all animations in one run cycle are "concatenated." You'll need to use
[UIView setAnimationDelay:3.0];
On the second animation.
Example Code
There are two ways to do this—using the standard begin/commit animations, or using the blocks method. This example uses the begin/commit animations code, which is what you have. The issue is because the animations are being concatenated, and without going into CA, the standard animation behavior is for one to be "forced" to end before the other runs. It has to do with run loops; Building Animation-Driven Interfaces from WWDC 2010 goes into depth about this. But the code to do what you want looks like this:
- (void)fadeOut {
[UIView beginAnimations:#"Animation2" context:NULL];
[UIView setAnimationDuration:3];
[self.testView setAlpha:0.00];
[UIView commitAnimations];
}
- (IBAction)animate {
[UIView beginAnimations:#"Animation1" context:NULL];
[UIView setAnimationDuration:3];
[self.testView setAlpha:1.00];
[UIView commitAnimations];
[self performSelector:#selector(fadeOut) withObject:nil afterDelay:3.0];
}
You have to force it to break up the run loop, basically. The key thing to remember is that animations are not executed sequentially, as you might expect code to be.
The blocks-based code looks like this. Note that I'm using the autorepeat option, which automatically repeats the animation. Note though that in the animation, you are setting a property, so by default after the animation completes the view will go back to being visible. Therefore, you have the set the property again to zero in the completion block.
- (IBAction)animate {
[UIView transitionWithView:self.testView duration:3.0 options:UIViewAnimationOptionAutoreverse animations:^{self.testView.alpha = 1.0;} completion:^(BOOL finished) {self.testView.alpha = 0.0;}];
}
Hopefully this helps!
I want my text box to blink (like the old LCD clocks).
Right now, I'm calling a myriad of NSTimers and selectors that wait, change the alpha, wait, then change it back. Even with this, it looks really bad, and I'm thinking I have to put an NSTimer to gradually change the alpha, but from what I hear they are not meant for things of that precision.
My thoughts are there must be a way to do this a lot better than how I am currently implementing it. It feels like hack.
Using an animation delegate might make it less "hacky":
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDelegate:self];
[UIView setAnimationDidStopSelector:#selector(animationDidStop:finished:context:)];
[myLabel setAlpha:0.0];
[UIView commitAnimations];
And then you can have your didStopSelector restart the animation:
- (void)animationDidStop:(NSString *)animationID finished:(NSNumber *)finished context:(void *)context {
[self displayLabel];
}
Depending on the animationID, you could take different actions, etc. Using UIView's setAnimationDelay might come in handy as well.
UIView also has a setDuration call for animations:
[UIView setAnimationDuration:0.1];
If you are building for iOS4, check the documentation since you should be using block-based animation calls rather than these delegate based ones.
you can set the alpha of the lable with annimation just like
to hide lable with animation
[UIView animateWithDuration:0.2 delay:0.1 options:UIViewAnimationOptionCurveEaseOut animations:^{
lblDistance.alpha=0;
} completion:^(BOOL finished) {
if (finished) {
}
}];
to show lable with animation
[UIView animateWithDuration:0.2 delay:0.1 options:UIViewAnimationOptionCurveEaseOut animations:^{
lblDistance.alpha=1;
} completion:^(BOOL finished) {
if (finished) {
}
}];
this is the best way anyone can animate and create a blinking lable........
I would use an NSTimer, but instead of messing with alpha channels i would either not draw the text (if that's even possible with Apple's very attribute-limited SDK), or if that's not possible you could always draw something on top of it (like a rectangle).
Using this approach of drawing something over your text would yield better performance.
Though some (okay most) would consider this a ugly hack, let me just say this, "If it looks right, it is right."
NSTimers and changing the alpha is a perfectly acceptable way of doing it - that's certainly what I do. If you are having problems, perhaps a code sample might help us see where the issue is?