Comments on: Simple iPhone Tutorial (Part 3)

By: Tutorial for iPhone programming « JongAm's blog

Tutorial for iPhone programming « JongAm's blog — Fri, 01 Jan 2010 05:18:36 +0000

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By: Mike

Mike — Wed, 24 Jun 2009 15:06:16 +0000

This was a really great tutorial – probably the best I’ve read so far. Thank you so much for taking the time to make it. Coming from a similar background as you (.NET for 5 years), I have found the Cocoa framework and XCode to be incredibly frustrating, and moving from C# to Objective-C has seemed like such a step backwards. Your tutorial has illuminated many things for me. Once again, thanks!

By: Goliad

Goliad — Thu, 04 Jun 2009 16:03:59 +0000

That was it! Thanks for the screenshot – it helps so much for those who are new to IB.

With a good learning from this thread, I want to see if I can combine this UITabBar example with Notification method used in the UISlide example mentioned in this thread. For example, when UISlide is pull to to a predermined point (say value=50), it would switch to Second Tab automatically.

By: miketeo

miketeo — Thu, 04 Jun 2009 05:47:56 +0000

@Goliad: It is likely that your tabBarController attribute is not initialized and point to the UITabBarController instance. You can link the attribute and the UITabBarController object in the Interface Buider (IB). Please refer to the second "window" in the screenshot.

By: Goliad

Goliad — Thu, 04 Jun 2009 03:57:24 +0000

That’s a really good example to show how tabBarController.selectedIndex to work. Thanks. I try to follow your example and add a button on SecondView so that I can jump back to FirstView without using its tab bar. So, I created a SecondViewController.h/m exactly as you did for FirstViewController. But when I hit
“changeToFirstView” button, the app threw an error, complaining the method

- (void)changeToFirstView:(id)sender {
tabBarController.selectedIndex = 0;
NSLog(@”changed to FirstView\n”);
}

Maybe I need to do something different than just copying the code for FirstViewController.

By: miketeo

miketeo — Thu, 04 Jun 2009 02:30:52 +0000

@goliad:
I have uploaded a working example on this. You can download it at http://miketeo.net/wp/wp-content/uploads/2008/08/tabbartest.zip

By: goliad

goliad — Wed, 03 Jun 2009 21:20:46 +0000

I want to jump to SecondTabView from OnOffTableCell, that is, whenever switchToggled (inside FirstTabView). I added the following code but could not get it to work.

OnOffTableCell.h ————————————–

@interface OnOffTableCell : UITableViewCell {
…
IBOutlet UITabBarController *tabBarController;
…
}
@property (nonatomic, retain) UITabBarController *tabBarController;

OnOffTableCell.m ————————–
@synthesize tabBarController;

- (void)switchToggled:(UISwitch*)control {
NSLog(@”OnOffTableCell:switchToggled: ….
[[NSNotificationCenter defaultCenter] …..
tabBarController.selectedIndex=1;
….
}

I must miss something (very new to Xcode). Could you suggest a few options to debug? Thanks.

By: miketeo

miketeo — Wed, 03 Jun 2009 05:43:44 +0000

@Goliad: Check out UITabBarController’s selectedIndex property. It allows you change the tab bar’s current selected view controller. So you can change this property in your first tab’s event handler to switch to another tab.

By: Goliad

Goliad — Wed, 03 Jun 2009 04:28:10 +0000

This helps understand how NotificationCenter works. Is a way to use an event inside First Tab to automatically switch to Second Tab without clicking Second Tab?

By: miketeo

miketeo — Mon, 27 Apr 2009 02:37:58 +0000

@Veri:
Thanks for pointing this out. I have fixed the link. It’s working now.