1. EEC-492/693/793 iPhone Application Development
Lecture 11
Wenbing Zhao & Nigamanth Sridhar
1/18/2019
EEC492/693/793 - iPhone Application Development

2. Outline Administrative Navigation Controller Assignments:
From now on: review your app/progress at the end of each session
Navigation Controller
Assignments:
The push and pop app
Continue building the calculator app
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EEC492/693/793 - iPhone Application Development
EEC492/693/793 - iPhone Application Development 2

3. Navigation Controller
The navigation controller (UINavigationController) can be used to manage a stack of view controllers
Stack: a data structure that manages a collection of objects
last in, first out / first in, last out
Push: add an object to a stack
Pop: remove an object from the stack
Navigation bar
Title of the top view controller
Left bar button to go to the previous view controller (pop)
Right bar button to allow editing etc.
1/18/2019
EEC492/693/793 - iPhone Application Development

4. EEC492/693/793 - iPhone Application Development
Example App: Mail
Top view controller’s title
Previous view controller’s title
Top view controller’s view
Top view controller’s toolbar
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EEC492/693/793 - iPhone Application Development

5. EEC492/693/793 - iPhone Application Development
How to Navigate
Push to add a view controller (to the UINavigationController’s stack)
- (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated;
Pop to remove a view controller from the stack (the previous one will become the top view controller)
- (UIViewController *)popViewControllerAnimated:(BOOL)animated;
Set to change the entire stack of view controllers
- (void)setViewControllers:(NSArray *)viewControllers animated:(BOOL)animated;
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EEC492/693/793 - iPhone Application Development

6. Pushing Your First View Controller
- (void)applicationDidFinishLaunching {
// Create a navigation controller
navController = [[UINavigationController alloc] init];
// Push the first view controller on the stack
[navController pushViewController:firstViewController
animated:NO];
// Add the navigation controller’s view to the window
[window addSubview:navController.view]; …. }
Where would you do this?
1/18/2019
EEC492/693/793 - iPhone Application Development

7. Push from within a View Controller on the Stack due to User Actions
- (void)someAction:(id)sender {
// Potentially create another view controller
UIViewController *viewController = ...;
[self.navigationController pushViewController:viewController animated:YES]; }
Where on earth does navigationController come from?!
It is defined in UIViewController as a property
Since our view controller inherited from UIViewController, we do have it as well
navigationItem is another property declared in UIViewController
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EEC492/693/793 - iPhone Application Development

8. Customizing Navigation
UINavigationItem: Describes appearance of the navigation bar
Title string or custom title view
Left & right bar buttons
More properties defined in UINavigationBar.h
Every view controller has a navigation item for customizing
Displayed when view controller is on top of the stack
Left Bar
Button Item
View Controller
Navigation Item
Title View
Right Bar
Button Item
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EEC492/693/793 - iPhone Application Development

9. EEC492/693/793 - iPhone Application Development
Displaying a Title
UIViewController already has a title property
@property(nonatomic,copy) NSString *title;
Navigation item inherits automatically
Previous view controller’s title is displayed in back button
viewController.title
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EEC492/693/793 - iPhone Application Development

10. EEC492/693/793 - iPhone Application Development
Left & Right Buttons
UIBarButtonItem
Special object, defines appearance & behavior for items in navigation bars and toolbars
Display a string, image or predefined system item
Target + action (like a regular button)
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EEC492/693/793 - iPhone Application Development

11. EEC492/693/793 - iPhone Application Development
Text Bar Button Item
- (void)viewDidLoad {
UIBarButtonItem *fooButton = [[UIBarButtonItem alloc]
style:UIBarButtonItemStyleBordered
target:self
self.navigationItem.leftBarButtonItem = fooButton;
[fooButton release]; }
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EEC492/693/793 - iPhone Application Development

12. EEC492/693/793 - iPhone Application Development
System Bar Button Item
- (void)viewDidLoad {
UIBarButtonItem *addButton = [[UIBarButtonItem alloc]
initWithBarButtonSystemItem:UIBarButtonSystemItemAdd
target:self
self.navigationItem.rightBarButtonItem = addButton;
[addButton release]; }
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EEC492/693/793 - iPhone Application Development

13. EEC492/693/793 - iPhone Application Development
Edit/Done Button
Very common pattern
Every view controller has one available
Target/action already set up
self.navigationItem.leftBarButtonItem = self.editButtonItem;
// Called when the user toggles the edit/done button
- (void)setEditing:(BOOL)editing animated:(BOOL)animated {
// Update appearance of views }
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EEC492/693/793 - iPhone Application Development

14. EEC492/693/793 - iPhone Application Development
Custom Title View
Arbitrary view in place of the title
UISegmentedControl *segmentedControl = ...
self.navigationItem.titleView = segmentedControl;
[segmentedControl release];
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EEC492/693/793 - iPhone Application Development

15. EEC492/693/793 - iPhone Application Development
Back Button
If you don’t like the default back button (using the title of the view controller), you can customize it
self.title there, CS193P!”;
UIBarButtonItem *heyButton = [[UIBarButtonItem alloc]
...];
self.navigationItem.backButtonItem = heyButton;
[heyButton release];
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EEC492/693/793 - iPhone Application Development

16. Combining Tab Bar and Navigation Controllers
You can combine the tab bar and navigation controllers to create multiple parallel hierarchies
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EEC492/693/793 - iPhone Application Development

17. Tab Bar + Navigation Controllers
View Controller
Navigation Item
View Controller
View Controller
Navigation Item
View Controller
View Controller
Navigation Item
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EEC492/693/793 - iPhone Application Development

18. Nesting Navigation Controllers (into Tab Bar Controller)
Create a tab bar controller
tabBarController = [[UITabBarController alloc] init];
Create each navigation controller
navController = [[UINavigationController alloc] init];
[navController pushViewController:firstViewController
animated:NO];
Add them to the tab bar controller
tabBarController.viewControllers = [NSArray arrayWithObjects:
navController,
anotherNavController,
someViewController,
nil];
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EEC492/693/793 - iPhone Application Development

19. Assignment: Push and Pop App
1/18/2019
EEC492/693/793 - iPhone Application Development