Understanding iphone View Controllers

• Build an iphone application
• Write the code you care about
• Extend in the future

Focus on data

One thing at a time

Screenfuls of content

 

navigation bar vs tab bar

navigation bar

hierarchy of content

drill down into great detail

 

tab-bar

self-contained modes

 

A Screenful of contents

slice of your application

views, data, logic

 

self-contained controller

List Controller --> Detail Controller  --> Photo Contoller

 

View Controllers in Interface Builder(storyboard)

lay out a view in interface builder

View controller is file's owner

hook up view outlet

create with -initWithNibName:bundle:

 

the second way:

View Controller in Code

override -loadview

create your views

set the view property

//subclass of UIViewController
- (void) loadView
{
    MyView *myView = [[MyView alloc] initWithFrame:frame];

    [self setView:myView];

    [myView release];

}

 

Hooks for Interesting Events

• Appear

                 Load your data

• Disappear

                Save your data

• Interface rotation
• Memory warnings

 

link view controller together

UINavigationController

manager a stack of view controllers

navigation bar 

 

Top view controller's view

Top view controller's title

Previous view controller't title (back bar item)

 

Modifying the navigation stack

adding a view controller

-pushViewController:animated:

remove

-popViewControllerAnimated:

 

setting up navigation

create

navigationController = [[UINavigationController alloc] init];

push the root view controller

[navigationController pushViewController:firstViewController animated:NO];

add its view to window

[window addSubView:navigationController.view];

 

Navigating

push from within a view controller on the stack

[self.navigationController pushViewController:anotherViewController animated:YES];

rarely call pop directly

Automatically invoked by the back button

 

Subclass UIViewController for each screenful

Set up in -applicationDidFinishLaunching

Push View controllers

 

TabBar

@implementation TabBarDemoDelegate

- (void) applicationDidFinishLaunching:(UIApplication *) application{

      [window addSubView:tabBarController.view];
      [window makeKeyAndVisible];

}

 

 Autoresizing your views programatically, or spring and struts

view.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;

 

 image

imageView.contentMode = UIViewContentModeScaleAspectFit;
imageView.backgroundColor =  [UIColor blackColor];