swift 怎么创建一个viewcontroller

1、新建一个Empty Application,只选Use Automatic Reference Counting,Use Core Data和Include Unit Tests不选。
2、Command+N　新建文件，选Cocoa Touch UIViewController subclass,SubClass of UIViewController,勾选with XIB for user interface(当然你也可以再建)。我这输的名字是MainViewController,最终生成MainViewController.h MainViewController.m MainViewController.xib三个文件。
3、打开(前缀)AppDelegate.h,代码如下:

[objc] view plaincopy
#import
#import "MainViewController.h"
@interface BIDAppDelegate : UIResponder

@property (strong, nonatomic) UIWindow *window;
@property (strong,nonatomic) MainViewController * controller;

@end

AppDelegate.m，修改(BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions　方法：

[objc] view plaincopy
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
// Override point for customization after application launch.
self.controller= [[MainViewController alloc] initWithNibName:@"MainViewController" bundle:nil];

UIView *mainView=self.controller.view;
CGRect mainViewFrame=mainView.frame;
mainViewFrame.origin.y+=[UIApplication sharedApplication].statusBarFrame.size.height;
//将y座标移到状态栏下
mainView.frame=mainViewFrame;
[self.window addSubview:mainView];
//载入

self.window.backgroundColor = [UIColor whiteColor];
[self.window makeKeyAndVisible];
return YES;
}

4、随便在MainViewController.xib中添加个控件，运行测试。