I am trying to find a way to animate two views in this way: they will start animating at different times but end their animations at the same time.
Think of a horse race where one horse starts after the other, but they both reach the finish line at the same time.
Its not a grouped animation. Also, how to I tell an animation to wait until a certain time to start?
Does anyone have any pointers on how to do this?
TIA
Use [UIView animateWithDuration:delay:options:animations:completion:]
Example:
[UIView animateWithDuration:1.0f animations:^{
// first animation code here
}];
[UIView animateWithDuration:0.5f delay:0.5f options:UIViewAnimationCurveEaseIn animations:^{
// second animation code here
} completion:^(BOOL finished) {
}];
Related
When a user makes a flick gesture on a UIScrollView, the UIScrollView gets a momentum and starts moving, then slow down and finally stop.
But how can I make this happen programmatically? I mean without a finger flicking, the UIScrollView just start moving automatically and then slow down to a speed of 0.
In my app I have made my UIScrollView unlike a normal UIScrollView (say it looks like a roller), so I want make a hint to the user that he can scroll it (and then everything get started!)
I have googled a lot but there seemed no way to solve my problem. The setContentOffset just couldn't make the natural "slow down and stop at somewhere ahead" effect.
Any idea would be appreciated.
Thanks in advance.
Try, something like this >
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDelegate:self];
[UIView setAnimationDelay:.8];
[UIView setAnimationCurve:UIViewAnimationCurveEaseOut];
[UIView setAnimationDuration:(abs(1-3)*0.3)];
self.myScroll.contentOffset = CGPointMake(0, 500);
[UIView commitAnimations];
It is not currently what you need, but you can customise this code, and may be all be ok)
or use this code>
[UIView animateWithDuration:2.
delay:0.3
usingSpringWithDamping:1.
initialSpringVelocity:7.
options:UIViewAnimationOptionCurveEaseInOut animations:^{
//Animations
self.myScroll.contentOffset = CGPointMake(0, 500);
}
completion:^(BOOL finished) {
//Completion Block
}];
I think it is like you want(animation with damping like swipe effect)
I have a UIView drawn in Storyboard which holds some buttons and which is called viewHolder.
I get a higher position rectForAnimationBefore
and a lower position rectForAnimationAfter
[UIView animateWithDuration:1.0
delay:0.0
options:UIViewAnimationOptionCurveEaseInOut
animations:nil completion:^(BOOL finish){
[self.viewHolder setFrame:rectForAnimationAfter];
}];
when this is excuted,the viewHolder do move down.After a second,it comes up as nothing was done.
I want to moveDown,but don't want moveUp Automatically.
Because autolayout in Storyboard?
By the way ,how to move it smoothly?
Thank you guys.
UPDATE:
[UIView animateWithDuration:1.0
delay:0.0
options:UIViewAnimationOptionCurveEaseInOut
animations:^{
[self.viewHolder setFrame:rectForAnimationAfter];
}
completion:^(BOOL finish){
}];
when I change code like this ,I can't move it down .
Here is my solution
unlock the autolayout!!!
First thing your animation block is nil. Here you should move your view down. At completion you are setting back you view without using any animation. For smoothness you need to move back your view animatedly.
I use animationWithDuration for animating elements. An I have 1 animation inserted in completion block of another.
[UIView animateWithDuration:2.0 delay:0.1 options:UIViewAnimationOptionCurveEaseInOut animations:^{
} completion:^(BOOL finished) {
[UIView animateWithDuration:2.0 delay:0.1 options:UIViewAnimationOptionCurveEaseInOut animations:^{
} completion:^(BOOL finished) {
... //and simple
}];
}];
So I have Stairs of six - nine elements of blocks of animationWithDuration.So how I can optimize this?
Sorry for my English.
If you have many nested animations the code quickly becomes very unreadable.
So the approach here is maybe to hold an array of all animation blocks and to iterate through them without nesting them.
One possible example how this looks in code is shown here:
Multiple UIView Animations Without Nested Blocks
Is there anyway to stop a UIView animation, but not jump to the end values?
I'd like to continue from where I am, instead of having a jerky looking 'snap' before it starts moving to it's new position
Here's the answer for other people who stumble here. Quite simple really, just pass 'options:UIViewAnimationOptionBeginFromCurrentState' into the options, and it will resume from it's current locaiton
[UIView animateWithDuration:2.0
delay:0.0
options:UIViewAnimationOptionBeginFromCurrentState
animations:^{
self.scrollView.contentOffset = CGPointMake(visibleFrame.origin.x, visibleFrame.origin.y);
}
completion:^(BOOL finished){}
];
I'm doing two animations on the same UIImageView, using blocks. Animations are not quite back to back, but almost; there is some logic inbetween.
animate UIImageView from one location on the view to another.
execute logic that determines whether image is allowed to stay there
if not allowed, undo the animation (UIImageView springs back to original location)
If I implement this as above, only the second animation shows (this is normal behavior from what I understand). If I nest the logic and the second animation block inside the completion block of the first, I see both animations, but there's a fair amount of code to jam into that completion block and it just seems ugly and out of place.
In the non-nested configuration, why does iOS want to cut short the previous animations and execute only the final one, and how can I force it to wait on the first one before going to the next? I don't think it needs to block the main thread or "sit and spin" in a completion block; I just want all animations to be shown. Tried adding delay to second animation to no avail.
Is this a job for CAKeyframeAnimation?
// first animation
[UIView animateWithDuration:0.5
delay:0.0
options: UIViewAnimationCurveLinear
animations:^{movingColor.center = newCenter;
movingColor.transform = scaleTransform;}
completion:^(BOOL finished){ NSLog(#"forward animation done");}];
if (/* ...color is allowed at that location */) {
// do some stuff
} else {
// undo the animation
[UIView animateWithDuration:0.5
delay:0.0
options: UIViewAnimationCurveLinear
animations:^{movingColor.center = origCenter;
movingColor.transform = scaleTransform;}
completion:^(BOOL finished){ NSLog(#"back animation done");}];
}
The second animation should be done conditionally inside the first's completion block. Putting it into a function will make it more readable.
- (void)moveColor:(UIView *)view to:(CGPoint)center delay:(NSTimeInterval)delay completion:(void (^)(BOOL finished))complete {
[UIView animateWithDuration:0.5 delay:delay options:UIViewAnimationCurveLinear animations:^{
view.center = center;
view.transform = scaleTransform; // probably don't need this
} completion:completion];
}
This way your logic can be separate from the animation code
- (void)someMethod {
[self moveColor:movingColor to:newCenter delay:0.0 completion:^(BOOL finished) {
if (/*it can stay*/) {
// stuff
} else {
[self moveColor:movingColor to:origCenter delay:2.0 completion:^(BOOL finished) {}];
}
}];
}
The correct way to do it is as you said to set the second one in the completition of the first one that is the correct way,
You can also adda delay on the start of the other, this may or may not work it depends on alot of variables
Your second animation will have a delay of .5 (time for first animation to complete )
[UIView animateWithDuration:0.5
delay:0.5
options: UIViewAnimationCurveLinear
animations:^{movingColor.center = origCenter;
movingColor.transform = scaleTransform;}
completion:^(BOOL finished){ NSLog(#"back animation done");}];
The animateWithDuration is executed asynchronously, and returns right away. That is, the next line of code is executed without waiting for the animation to finish. You either put your code in the completion block if you want it to be executed after the animation is finished, or you accept that the second animation is started (thus canceling the first) immediately.
If you want to indicate to the user that something was wrong by starting the animation, but not completing it, you could execute the second animation with a delay. Remember to also set the the UIViewAnimationOptionBeginFromCurrentState option if you delay the second animation with less than the duration of the first:
[UIView animateWithDuration:0.5
delay:0.25 //or some number
options: (UIViewAnimationCurveLinear | UIViewAnimationOptionBeginFromCurrentState)
animations:^{movingColor.center = origCenter;
movingColor.transform = scaleTransform;}
completion:^(BOOL finished){ NSLog(#"back animation done");}];