源码03-02-07-LoadView

//
//  AppDelegate.m
//  07-控制器View的创建
#import "AppDelegate.h"

@interface AppDelegate ()

@end

@implementation AppDelegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    // Override point for customization after application launch.

    self.window = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];

    UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Main" bundle:nil];

    // 加载箭头指向的控制器
    UIViewController *vc = [storyboard instantiateInitialViewController];

    self.window.rootViewController = vc;

    [self.window makeKeyAndVisible];

    return YES;
}
@end

//
//  ViewController.m
//  07-控制器View的创建
#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

// loadView作用：自定义控制器的view

// loadView什么时候调用：第一次使用控制器的view的时候调用

// 注意：在这个方法中如果没有自定义view,就不能获取控制器的view

// 一旦重写了这个方法，就不要调用[super loadView]
// 如果重写了这个方法，就不会去加载storyboard描述的控制器的View
- (void)loadView
{
  //  self.view.backgroundColor = [UIColor redColor];

//    // 创建控制器view
    self.view = [[UIView alloc] initWithFrame:[UIScreen mainScreen].bounds];
//
    self.view.backgroundColor = [UIColor purpleColor];
}

//- (UIView *)view
//{
//    if (_view == nil) {
//        [self loadView];
//
//        [self viewDidLoad];
//    }
//    return _view;
//}

#pragma mark - 直接不实现就是系统默认的做法
//- (void)loadView
//{
//    // super ->  UIViewController
//    // 系统默认的做法,一定不要这样写
//    [super loadView];
//
//}

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end