新建RootViewController 继承于 UIViewController

新建RootView 继承于 UIView

AppDelegate.m 中引入 #import "RootViewController.h"

#pragma mark - 重写

#pragma mark dealloc

- (void)dealloc

{

    [_window release];

    [super dealloc];

}

    //设置window

    self.window = [[[UIWindow alloc] init] autorelease];

    self.window.frame = [UIScreen mainScreen].bounds;

    self.window.backgroundColor = [UIColor whiteColor];

    [self.window makeKeyAndVisible];

    // 设置根视图控制器

    RootViewController *rootVC = [[RootViewController alloc] init];

    self.window.rootViewController = rootVC;

    [rootVC release];

RootViewController.m 中引入 #import "RootView.h"

@interface RootViewController ()

@property (nonatomic, retain) RootView *rootView;

@end

#pragma mark - 重写

#pragma mark dealloc

- (void)dealloc

{

    [_rootView release];

    [super dealloc];

}

编写 loadView 函数，函数中永远仅仅写三句话

- (void)loadView

{

    // 设置当前视图为根视图

    self.rootView = [[RootView alloc] initWithFrame:[UIScreen mainScreen].bounds];

    self.view = self.rootView;

    [_rootView release];

}

能够在 RootView.m 中编写视图了。