UIScreen,UIView,UIWindow和UIViewController的介绍和区别

来源：互联网发布：图文网站源码编辑：程序博客网时间：2024/04/27 15:00

一、参考

View Programming Guide for iOS

http://developer.apple.com/library/ios/#documentation/WindowsViews/Conceptual/ViewPG_iPhoneOS/Introduction/Introduction.html

View Controller Programming Guide for iOS

http://developer.apple.com/library/ios/#featuredarticles/ViewControllerPGforiPhoneOS/Introduction/Introduction.html

UIScreen Class Reference

http://developer.apple.com/library/ios/#documentation/UIKit/Reference/UIScreen_Class/Reference/UIScreen.html

UIView Class Reference

http://developer.apple.com/library/ios/#documentation/UIKit/Reference/UIView_Class/UIView/UIView.html

UIWindow Class Reference

http://developer.apple.com/library/ios/#documentation/UIKit/Reference/UIWindow_Class/UIWindowClassReference/UIWindowClassReference.html

UIViewController Class Reference

http://developer.apple.com/library/ios/#documentation/UIKit/Reference/UIViewController_Class/Reference/Reference.html

二、区别

1、UIScreen可以获取设备屏幕的大小。

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// 整个屏幕的大小 {{0, 0}, {320, 480}}
CGRect bounds = [UIScreen mainScreen].bounds;
NSLog(@"UIScreen bounds: %@", NSStringFromCGRect(bounds));
 
// 应用程序窗口大小 {{0, 20}, {320, 460}}
CGRect applicationFrame = [UIScreen mainScreen].applicationFrame;
NSLog(@"UIScreen applicationFrame: %@", NSStringFromCGRect(applicationFrame));

2、UIView对象定义了一个屏幕上的一个矩形区域，同时处理该区域的绘制和触屏事件。
可以在这个区域内绘制图形和文字，还可以接收用户的操作。一个UIView的实例可以包含和管理若干个子UIView。

ViewController.m

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- (void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:animated];
    UIView* myView = [[UIView alloc] initWithFrame:CGRectMake(10, 10, 100, 100)];
    myView.backgroundColor=[UIColor redColor];
    [self.view addSubview:myView];
}

3、UIWindow对象是所有UIView的根，管理和协调的应用程序的显示
UIWindow类是UIView的子类，可以看作是特殊的UIView。一般应用程序只有一个UIWindow对象，即使有多个UIWindow对象，也只有一个UIWindow可以接受到用户的触屏事件。

AppDelegate.m

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- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    UIWindow *myWindow = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    myWindow.backgroundColor=[UIColor whiteColor];
    [myWindow makeKeyAndVisible];
    _window = myWindow;
    returnYES;
}

4、UIViewController对象负责管理所有UIView的层次结构，并响应设备的方向变化。

AppDelegate.m

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- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    UIWindow *myWindow = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    myWindow.backgroundColor=[UIColor whiteColor];
    UIViewController *myViewController = [[UIViewController alloc] initWithNibName:nil bundle:nil];
    myWindow.rootViewController = myViewController;
    [myWindow makeKeyAndVisible];
    _window = myWindow;
    returnYES;
}

三、完整的代码

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// ViewController.h
#import <UIKit/UIKit.h>
@interface ViewController : UIViewController
@end
 
// ViewController.m
#import "ViewController.h"
@implementation ViewController
- (void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];
    UIView* myView = [[UIView alloc] initWithFrame:CGRectMake(10, 10, 100, 50)];
    myView.backgroundColor=[UIColor redColor];
    [self.view addSubview:myView];
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
    returnYES;
}
@end
 
// AppDelegate.h
#import <UIKit/UIKit.h>
@classViewController;
@interface AppDelegate : UIResponder <UIApplicationDelegate>
@property (strong, nonatomic) UIWindow *window;
@property (strong, nonatomic) ViewController *viewController;
@end
 
// AppDelegate.m
#import "AppDelegate.h"
#import "ViewController.h"
@implementation AppDelegate
@synthesize window = _window;
@synthesize viewController = _viewController;
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    self.viewController = [[ViewController alloc] initWithNibName:nil bundle:nil]; 
    self.window.rootViewController = self.viewController;
    [self.window makeKeyAndVisible];
    returnYES;
}
@end
 
// main.m
#import <UIKit/UIKit.h>
#import "AppDelegate.h"
intmain(intargc,char*argv[]) {
    @autoreleasepool {
        returnUIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class]));
    }
}

转载自：http://blog.csdn.net/kuqideyupian/article/details/7731942