iOS: UIView animation block method animating weirdly on multiple fires - ios

Question

I am doing page swipe animation with 2 UIWebViews to render book page effect.
Swipe is fired on next and previous click.
Animation works fine until the next or previous button is clicked multiple times in succession.
Here's what I am doing:
display webview1 by default
on right swipe, make webview1 frame x origin negative to hide it. And make webview2 frame x origin as 0 to display it.
similarly for left swipe.
Here is my code to swipe:
-(void)pageChange
{
#try{
[UIView commitAnimations];
NSString *finalPath;
finalPath = [NSString stringWithFormat:#"%#/%#",self.strBookPath, [arrHtmlPages objectAtIndex:currentPage]];
NSData *htmlData = [NSData dataWithContentsOfFile:finalPath];
__block CGRect basketTopFrame = webViewPage.frame;
[UIView animateWithDuration:DURATION delay:0.0f options:UIViewAnimationOptionCurveEaseOut animations:^{
if (_webview2.frame.origin.x == self.view.frame.size.width) {
basketTopFrame.origin.x = -(self.view.frame.size.width);
[webViewPage setFrame:basketTopFrame];
basketTopFrame.origin.x = self.view.frame.size.width;
_webview2.frame = basketTopFrame;
[_webview2 loadData:htmlData MIMEType:#"text/html" textEncodingName:#"UTF-8" baseURL:[NSURL fileURLWithPath:self.strBookPath isDirectory:YES]];
[UIView animateWithDuration:DURATION delay:0.0 options:UIViewAnimationOptionCurveEaseIn animations:^{
//basketTopFrame = webViewPage.frame;
basketTopFrame.origin.x = 0;
_webview2.frame = basketTopFrame;
//NSLog(#"web1: %f",webViewPage.frame.origin.x);
//NSLog(#"web2 : %f", _webview2.frame.origin.x);
} completion:^(BOOL finished){
basketTopFrame.origin.x = self.view.frame.size.width;
webViewPage.frame=basketTopFrame;
}];
} else {
basketTopFrame.origin.x = -(self.view.frame.size.width);
[_webview2 setFrame:basketTopFrame];
basketTopFrame.origin.x = self.view.frame.size.width;
webViewPage.frame = basketTopFrame;
[webViewPage loadData:htmlData MIMEType:#"text/html" textEncodingName:#"UTF-8" baseURL:[NSURL fileURLWithPath:self.strBookPath isDirectory:YES]];
[UIView animateWithDuration:DURATION delay:0.0 options:UIViewAnimationOptionCurveEaseIn animations:^{
//basketTopFrame = webViewPage.frame;
basketTopFrame.origin.x = 0;
webViewPage.frame = basketTopFrame;
//NSLog(#"web1 in: %f",webViewPage.frame.origin.x);
//NSLog(#"web2 in: %f", _webview2.frame.origin.x);
} completion:^(BOOL finished){
basketTopFrame.origin.x = self.view.frame.size.width;
_webview2.frame=basketTopFrame;
}];
}
} completion:^(BOOL finished){
NSLog(#"web1 in: %f",webViewPage.frame.origin.x);
NSLog(#"web2 in: %f", _webview2.frame.origin.x);
}];
}#catch(NSException *e){
NSLog(#"exception : %#",e.description);
}
}
This code is just for right swipe. Left swipe also has similar code.
- (IBAction)btnNext_click:(id)sender {
[self swipeRight:nil]; //this calls pageChange()
}
When the above method is fired many times with very very short interval(user clicks on it rigorously), then both the webviews get frame x origin as width of device(in my case 768), and both get hidden.
Where am I getting wrong? How do I solve this?

Answer 1

There is easy solution for this: Disable buttons during animation. Look for userInteractionEnabled property for buttons and set it to NO during animation. When animation finishes, enable it again. It is very convenient with block based animations as you will enable it in completion handler. Hope this helps.