iOS：使用导航栏

要求使用ARC

//
//  main.m
//  Hello
//
//  Created by lishujun on 14-8-28.
//  Copyright (c) 2014年 lishujun. All rights reserved.
//

#import <UIKit/UIKit.h>

// --------------视图控制器对象--------------
@interface HelloWorldViewController : UIViewController
@end

@implementation HelloWorldViewController

-(void) loadView
{
    NSLog(@"load View");
    //创建视图对象
    UIView *contentView = [[UIView alloc]initWithFrame:[[UIScreen mainScreen] applicationFrame]];
    contentView.backgroundColor = [UIColor lightGrayColor];
    self.view = contentView;

    //设置导航栏按钮，被加载的到UINavigationController才可以使用这个属性？
    self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"Next" style:UIBarButtonItemStylePlain target:self action:@selector(pushView:)];
    self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"Prev" style:UIBarButtonItemStylePlain target:self action:@selector(popView:)];
}

-(void) pushView:(id)sender
{
    NSLog(@"push view");
    [self.navigationController pushViewController:[[HelloWorldViewController alloc]init] animated:YES];
}

-(void) popView:(id)sender
{
    NSLog(@"pop view");
    [self.navigationController popViewControllerAnimated:YES];
}

@end

// ----------------委托对象--------------------
@interface HelloWorldAppDelegate : NSObject <UIApplicationDelegate>
{
    IBOutlet UIWindow *window;
}

@property (nonatomic, retain) UIWindow *window;
@property (nonatomic, retain) UINavigationController *nav;

@end

@implementation HelloWorldAppDelegate

@synthesize window;
@synthesize nav;

-(void) applicationDidFinishLaunching:(UIApplication *)application
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen]bounds]];
    HelloWorldViewController *viewController = [[HelloWorldViewController alloc]init];

    self.nav = [[UINavigationController alloc]initWithRootViewController: viewController];
    self.window.rootViewController = self.nav;
    [self.window makeKeyAndVisible];
}
@end

// ---------------程序入口---------------------
int main(int argc, char * argv[])
{
    @autoreleasepool {
        return UIApplicationMain(argc, argv, nil, @"HelloWorldAppDelegate");
    }
}