viewWillAppear firing multiple times

[barfoon]

Hello - love this control!

Noticed that viewWillAppear is firing multiple times whenever you revisit a tab's view controller?

How can this be adjusted so this method only fires once every time a user revisits a tab?

Thanks,

[davidmorford]

Thanks... the area to look would be in TBKTabBarController.m in the implementation of the tabBar:didSelectTabAtIndex: message. If it is firing more than once, that would be a bug on me as it should fire just once when it appears as the result of a selected event. Will take look this evening or tomorrow to see if I can repro and push a fix if needed to the current master and the arc branch (still very experimental) as well.

[barfoon]

Hi Dave,

Thanks very much for a prompt reply.

After testing a bit more, it appears it's being fired in
the abBar:didSelectTabAtIndex: method with the line:
[self.selectedViewController viewWillAppear:NO];

And then also again in the loaded viewController.

Not sure how you want to / going to update the Git project, but your message
helped me.

Thanks again!
-Nick

On Tue, Oct 11, 2011 at 5:16 PM, Dave Morford <
reply@reply.github.com>wrote:

Thanks... the area to look would be in TBKTabBarController.m in the
implementation of the tabBar:didSelectTabAtIndex: message. If it is firing
more than once, that would be a bug on me as it should fire just once when
it appears as the result of a selected event. Will take look this evening or
tomorrow to see if I can repro and push a fix if needed to the current
master and the arc branch (still very experimental) as well.

Reply to this email directly or view it on GitHub:
#1 (comment)

[davidmorford]

Glad it helped. I'll push a fix after taking a look this evening for any side effects if changing that and cite the report. Cheers!

[barfoon]

Were you able to see any side effects of taking out that viewWillAppear
call?
Will you remove the viewDidAppear and setNeedsLayout calls also?

Cheers,

On Tue, Oct 11, 2011 at 7:17 PM, Dave Morford <
reply@reply.github.com>wrote:

Glad it helped. I'll push a fix after taking a look this evening for any
side effects if changing that and cite the report. Cheers!

Reply to this email directly or view it on GitHub:
#1 (comment)

[davidmorford]

So far I see no bad side effects as a result of removing the calls to viewWillAppear and viewDidAppear in tabBar:didSelectTabAtIndex:. What I am considering is what the proper behavior should be. I think the current behavior is correct except in loading case. Changes that would handle the scenarios are:

1. If the selectedController is not loaded, do not call viewWillAppear/viewDidAppear. The controller lifecycle should handle that it.
2. Calling viewWillAppear/viewDidAppear on a loaded view controller should be done by default to allow the contained controller to respond to changes in the application or device state and the controller data model. For instance, think calling reloadData if the contained controller was a UITableViewController for instance.
3. A BOOL property on TBKTabBarController to prevent viewWillAppear/Disappear when selecting tabs and/or a property on TBKTabBarItemDataSource to prevent viewWillAppear/Disappear calls on a per controller/tab item basis that can be overridden through the UIViewController (TBKTabBarControllerItem) category that provides the convenience implementation of TBKTabBarItemDataSource.

[barfoon]

Hi David - I noticed tonight that viewWillAppear fires multiple times under the iPhone 5.0 simulator, but only once (and works properly) under the iPhone 4.3 simulator. Hopefully that helps...!

[barfoon]

Looks like this problem is detailed here too: http://stackoverflow.com/questions/7830830/ios-different-addsubview-behavior-between-ios-4-3-and-5-0