A view(UIView subclass) represents a rectangular area.

a view has only one superview - (UIView *) superview;

But can have many(or zero) subviews -(NSArray *) subviews;

subview order matters.

 

UIWindow

the UIView at the top of the view hierarchy.

Only have one UIWindow in an iOS application.

It is all about UIViews.

always use CGFloat for graphics. 

CGPoint p = CGPointMake(34.5,22.0);p.x += 20; CGSize CGSizeMake CGRect CGRectMake

coordinate system is upper left -----> x 

units are "points" not pixels!

@property CGFloat contentScaleFactor

view's 3 properties

@property CGRect bounds;//internal@property CGPoint center;//the center in your superview's coordinate system@property CGRect frame;// a rectangle in your superview's coordinate space which entirely contains your view's bounds.size

when view rotated, bounds and frame are different.

to customize view

drag out a generic UIView from the palette and use the Inspector to change the class of the UIView to your custom class.

autorotation

implement the following method in your controller

-(BOOL) shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation) orientation{}

content mode

By default, when your UIView's bounds change, no redraw.

luckily, there is a UIView @property to control this.

@property (nonatomic) UIViewContentMode contentMode;

Default is UIViewContentModeScaleToFill.

protocol

@protocol Foo 
     
      - (void) doSomething;@optional@required@property@end
     

UIGestureRecognizer

how can we react to certain "gestures"?

there are two steps to using a gesture recognizer

• adding a gesture recognizer to a UIView
• provide a gesture handler

 

UIViewController

mvcs working together

how do we switch the screen to show another mvc

controller of controller

UINavigationController

it's special because we can set its rootViewController outlet to another MVC...

A UI element in a view can segue to the other MVC and its view will now appear in the UINavigationController

to create a segue, you hold down ctrl and drag from the button to the other view controller.

Is Initial View Controller

Embedded in Navigation Controller

UIView obtained from the view property of the UIViewController most recently pushed (or root).

NSString obtained from the title property of the UIViewController most recently pushed (or root).

An NSArray of UIBarButtonItems obtained from the toolbarItems property of the UIViewController most recently pushed.

back button -- title property of the previous view

- (IBAction) rentEquipment{    if(self.snowTraversingTalent ==Skiing){         [self performSegueWithIdentifier:@"AskAboutSkis" sender:self];    }}

prepareForSegue

- (void) prepareForSegue: (UIStoryboardSegue *) segue{}