iPhone开发多视图技术总结之三：Navigation .

实现的功能：通过Navigation，实现多视图切换。这是使用最多的一种多视图实现方式。


关键词：多视图 Navigation UINagivationController



1、创建一个Empty Application工程，命名为：MultiView-Navigation，如下图
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2、选中工程中的Group MultiView-Tab，然后按住CMD（Windows键）+N，新建视图控制器FirstViewController，如下图
[img]

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3、依照上步操作，新建视图控制器SecondViewController





4、修改AppDelegate.h，修改后如下：

#import <UIKit/UIKit.h>
#import "FirstViewController.h"
#import "SecondViewController.h"

@interface AppDelegate : UIResponder <UIApplicationDelegate>

@property (strong, nonatomic) UIWindow *window;

@property (strong, nonatomic) UINavigationController *navigationController;//导航视图控制器对象
@end

5、修改AppDelegate.m，主要是修改didFinishLaunchingWithOptions方法，修改后如下：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    // Override point for customization after application launch.
    FirstViewController *firstViewController = [[FirstViewController alloc]initWithNibName:@"FirstViewController" bundle:nil];
    //初始化navigationController，将firstViewController作为根视图控制器
    navigationController = [[UINavigationController alloc]initWithRootViewController:firstViewController];//备注1
    [self.window addSubview:navigationController.view];
    
    self.window.backgroundColor = [UIColor whiteColor];
    [self.window makeKeyAndVisible];
    return YES;
}

6、修改FirstViewController.h，添加goSecondView方法：

#import <UIKit/UIKit.h>
#import "SecondViewController.h"
@interface FirstViewController : UIViewController

-(void)goSecondView;
@end

7、修改FirstViewController.m，主要是修改initWithNibName及实现goSecondView方法：

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
        self.title = @"First View";
        self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc]initWithTitle:@"SecondView" style:UIBarButtonItemStyleBordered target:self action:@selector(goSecondView)];
        
    }
    return self;
}

-(void)goSecondView{
    SecondViewController *secondViewController = [[SecondViewController alloc]initWithNibName:@"SecondViewController" bundle:nil];
    //跳转到secondViewController
    [self.navigationController pushViewController:secondViewController animated:YES];//备注2
}

8、视图控制器SecondViewController，仅修改SecondViewController.m中的initWithNibName方法，如下：

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
        self.title = @"SecondView";
    }
    return self;
}

09.} 
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
        self.title = @"SecondView";
    }
    return self;
}代码解释：

备注1：firstViewController被push到navigationController中。

备注2：self.navigationController的英文注释为：// If this view controller has been pushed onto a navigation controller, return it.

所以，self.navigationController返回的正是备注1中的navigationController。



9、编译、运行，效果如下：
[img]

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[img]

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10、Navigation通常与TableView搭配使用，一个单视图应用，现在搭配上Navigation将其修改为多视图应用。




11、将TableView示例工程复制一份名称修改为TableViewDemo-Nav，打开该工程进行修改。




12、首先，修改AppDelegate，添加UINavigationController的实例，AppDelegate.h修改后如下：

#import <UIKit/UIKit.h>

@class ViewController;

@interface AppDelegate : UIResponder <UIApplicationDelegate>

@property (strong, nonatomic) UIWindow *window;

@property (strong, nonatomic) ViewController *viewController;
//添加navigationController
@property (strong, nonatomic) UINavigationController *navigationController;
@end

修改AppDelegate.m中的didFinishLaunchingWithOptions方法，如下：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];
    // Override point for customization after application launch.
    self.viewController = [[[ViewController alloc] initWithNibName:@"ViewController" bundle:nil] autorelease];
    //注释掉下面一行代码
    /*
    self.window.rootViewController = self.viewController;*/
    //添加如下代码
    self.navigationController = [[UINavigationController alloc]initWithRootViewController:self.viewController];
    [self.window addSubview:self.navigationController.view];
    
    [self.window makeKeyAndVisible];
    return YES;
}

13、新建视图控制器AppViewController（带xib）,如下：

[img]

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14、ViewController.h修改后如下：

#import <UIKit/UIKit.h>
#import "AppViewController.h"
@interface ViewController : UIViewController

@property(nonatomic,retain)NSMutableArray *apps;
@property(nonatomic,retain)AppViewController *appViewController;
@end

ViewController.m中主要是实现了-(void)tableView:(UITableView*)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath方法，如下：

//实现didSelectRowAtIndexPath
-(void)tableView:(UITableView*)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{
    NSString *imageName = [NSString stringWithFormat:@"%d",[indexPath row]+1];
    NSString *appName = [apps objectAtIndex:[indexPath row]];
    //初始化appViewController
    appViewController = [[AppViewController alloc]initWithNibName:@"AppViewController" bundle:nil];
    //传递参数
    appViewController.appName = appName;
    appViewController.appIconName = imageName;
    //跳转到appViewController
    [self.navigationController pushViewController:appViewController animated:YES];
}

15、AppViewController.h如下

#import <UIKit/UIKit.h>

@interface AppViewController : UIViewController

@property(strong,nonatomic)NSString *appName;
@property(strong,nonatomic)NSString *appIconName;

@property(strong,nonatomic)IBOutlet UILabel *appNameLabel;
@property(strong,nonatomic)IBOutlet UIImageView *appIconImgView;
@end

注意：将输出口与AppViewController.xib中的UI控件相连。AppViewController.xib如下:

[img]

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#import "AppViewController.h"

@interface AppViewController ()

@end

@implementation AppViewController
@synthesize appName;
@synthesize appIconName;
@synthesize appNameLabel;
@synthesize appIconImgView;

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        self.title = @"AppViewController";
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.
    
    self.appNameLabel.text = appName;
    self.appIconImgView.image = [UIImage imageNamed:appIconName];
    
    NSLog(@"appName=%@,appIconName=%@",appName,appIconName);
}

- (void)viewDidUnload
{
    [super viewDidUnload];
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
    appName = nil;
    appIconName = nil;
    appNameLabel = nil;
    appIconImgView = nil;
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}

@end

16、运行效果如下：
[img]

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