CODEWITHSUNDEEP
iosobjective-cuiviewanimation
Peer Mohamed Thabib
Peer Mohamed Thabib

Reputation: 705

UIView Animation happens faster than specified seconds

I have a view with an image shows some text in it. I need to perform animation which reveals the character by character in the end the complete text has to be displayed.

I have a logo view in my interface, over that I have animate view. for animate view the Leading, trailing, top and bottom constraints are set based on the superView (logo view).

I have tried following code but the duration which I have specified is not working properly.

   - (void) animateLogo {
    [UIView animateWithDuration:10.0 animations:^{
        NSLog(@"animation started");
        if (self.animateViewLeadingConstraint.constant < 94) { //94 is the total width of the logo view
            self.animateViewLeadingConstraint.constant = self.animateViewLeadingConstraint.constant + 1;
        } else {
            self.animateViewLeadingConstraint.constant = 0;
        }
    } completion:^(BOOL finished) {
        NSLog(@"animation ended");
        [self.animateView layoutIfNeeded];
        [self animateLogo];
    }];
}

I have attached the log for time duration

2016-08-01 17:55:27.317 sample[20361:481531] animation started
2016-08-01 17:55:27.318 sample[20361:481531] animation ended
2016-08-01 17:55:27.318 sample[20361:481531] animation started
2016-08-01 17:55:27.318 sample[20361:481531] animation ended
2016-08-01 17:55:27.318 sample[20361:481531] animation started
2016-08-01 17:55:27.319 sample[20361:481531] animation ended
2016-08-01 17:55:27.319 sample[20361:481531] animation started
2016-08-01 17:55:27.319 sample[20361:481531] animation ended

I am not sure what mistake I have made in above code or am I misunderstood the UIView Animation concept

Any help or hint would greatly appreciated.

Upvotes: 0

Views: 658

Answers (2)

Peer Mohamed Thabib
Peer Mohamed Thabib

Reputation: 705

Finally, I have got the solution based on @stevekohls comments 

- (void) animateLogo {
    self.animateViewLeadingConstraint.constant = 0;
    [UIView animateWithDuration:5.0f animations:^{
        self.animateViewLeadingConstraint.constant = 94.0;
        [self.view layoutIfNeeded];
    } completion:^(BOOL finished) {
        [UIView animateWithDuration:0.5f animations:^{
            self.animateView.alpha = 0;
        } completion:^(BOOL finished) {
                self.animateViewLeadingConstraint.constant = 0;
                [self.view layoutIfNeeded];
                self.animateView.alpha = 1.0f;
                [self animateLogo];
        }];
    }];
}

Upvotes: 0

stevekohls
stevekohls

Reputation: 2255

See this answer: How do I animate constraint changes?

You should be calling layoutIfNeeded on the animated view's superview before your animation block, and in the animations: block itself. The first call makes sure any layout changes are applied. Assuming logoView is the superview of animateView:

- (void) animateLogo {
    self.animateViewLeadingConstraint.constant = 0.0;
    [self.logoView layoutIfNeeded];
    [UIView animateWithDuration:10.0 animations:^{
        NSLog(@"animation started");
        self.animateViewLeadingConstraint.constant = 94.0;
        [self.logoView layoutIfNeeded];
    } completion:^(BOOL finished) {
        NSLog(@"animation ended");
    }];
}

Upvotes: 1

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