IOS开发学习笔记（五）——多视图应用程序之框架分析

我们之前学习了Single View Application的创建和设置，当然我们的程序不可能只有一个界面，所以我们需要对多视图进行支持。

我们首先来看看最简单的多视图应用：Utility Application。我们新建一个工程，选择Utility类型，结果发现我们现在有2个ViewController：MainViewController和FlipsViewController。分别有.xib(xml格式的UI描述文件，类似于Android中的layout文件)、.h头文件、.m实现文件。

接下来我们通过分析源代码查看程序的执行逻辑：

对于MainView，我们看到xib右下角有个"info"的这种按钮，在执行时可以切换到FlipsView，我们查看源码得到的结果是：

// info按钮点击事件
- (IBAction)showInfo:(id)sender
{
// 获得FlipsViewController
FlipsideViewController *controller = [[FlipsideViewController alloc] initWithNibName:@"FlipsideViewController" bundle:nil];
// 设置Controller的delegate为MainView
controller.delegate = self;
// 设置切换动画
controller.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
// 设置呈现Controller
[self presentViewController:controller animated:YES completion:nil];
}

对于FlipsView，我们查看“Done”按钮的事件处理源码：

// Done按钮事件处理
- (IBAction)done:(id)sender
{
[self.delegate flipsideViewControllerDidFinish:self];
}

接下来我们看一个Master-Detail的例子。Master-Detail类似于PC下的多窗口应用程序，主窗口中列表显示子窗口项，点击单项进入该项详情页面。
我们新建立一个工程之后分析：Master-Detail程序同样存在一个MasterView和一个DetailView。

其中MasterView中的代码：

//
//  MasterViewController.m
//  MasterDetailDemo
//
//  Created by Sam Wang on 13-5-27.
//  Copyright (c) 2013年 com.freesoft. All rights reserved.
//

#import "MasterViewController.h"

#import "DetailViewController.h"

@interface MasterViewController () {
NSMutableArray *_objects;
}
@end

@implementation MasterViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// 初始化标题
self.title = NSLocalizedString(@"Master", @"Master");
}
return self;
}

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

// 初始化Add按钮样式
UIBarButtonItem *addButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd target:self action:@selector(insertNewObject:)];
self.navigationItem.rightBarButtonItem = addButton;
}

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

- (void)insertNewObject:(id)sender
{
// 插入新条目
if (!_objects) {
_objects = [[NSMutableArray alloc] init];
}
[_objects insertObject:[NSDate date] atIndex:0];
NSIndexPath *indexPath = [NSIndexPath indexPathForRow:0 inSection:0];
[self.tableView insertRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationAutomatic];
}

#pragma mark - Table View

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
// 设置区域
return 1;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
// 条目数
return _objects.count;
}

// Customize the appearance of table view cells.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
// 显示条目
static NSString *CellIdentifier = @"Cell";

UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
}

NSDate *object = _objects[indexPath.row];
cell.textLabel.text = [object description];
return cell;
}

- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath
{
// Return NO if you do not want the specified item to be editable.
return YES;
}

- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
if (editingStyle == UITableViewCellEditingStyleDelete) {
[_objects removeObjectAtIndex:indexPath.row];
[tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationFade];
} else if (editingStyle == UITableViewCellEditingStyleInsert) {
// Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view.
}
}

/*
// Override to support rearranging the table view.
- (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)fromIndexPath toIndexPath:(NSIndexPath *)toIndexPath
{
}
*/

/*
// Override to support conditional rearranging of the table view.
- (BOOL)tableView:(UITableView *)tableView canMoveRowAtIndexPath:(NSIndexPath *)indexPath
{
// Return NO if you do not want the item to be re-orderable.
return YES;
}
*/

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
// 选择某项条目
if (!self.detailViewController) {
self.detailViewController = [[DetailViewController alloc] initWithNibName:@"DetailViewController" bundle:nil];
}
NSDate *object = _objects[indexPath.row];
self.detailViewController.detailItem = object;
[self.navigationController pushViewController:self.detailViewController animated:YES];
}

@end

Detail-View代码分析：

//
//  DetailViewController.m
//  MasterDetailDemo
//
//  Created by Sam Wang on 13-5-27.
//  Copyright (c) 2013年 com.freesoft. All rights reserved.
//

#import "DetailViewController.h"

@interface DetailViewController ()
- (void)configureView;
@end

@implementation DetailViewController

#pragma mark - Managing the detail item

- (void)setDetailItem:(id)newDetailItem
{
if (_detailItem != newDetailItem) {
_detailItem = newDetailItem;

// Update the view.
[self configureView];
}
}

- (void)configureView
{
// Update the user interface for the detail item.
// 显示条目内容

if (self.detailItem) {
self.detailDescriptionLabel.text = [self.detailItem description];
}
}

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

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

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
// 显示标题
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
self.title = NSLocalizedString(@"Detail", @"Detail");
}
return self;
}

@end

最后我们看一个Tabbed Application，这种类型的应用还是非常多的。我们以一个简单的例子来说明如果我们需要添加一个Tab页面的情况：

我们添加一个controller，我们选择New->iOS->Cocoa Touch中的Object-C Class，并且命名为：ThirdViewController，创建XIB文件。
我们修改AppDelegate.m代码，增加一个viewController：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
// Override point for customization after application launch.
UIViewController *viewController1 = [[FirstViewController alloc] initWithNibName:@"FirstViewController" bundle:nil];
UIViewController *viewController2 = [[SecondViewController alloc] initWithNibName:@"SecondViewController" bundle:nil];
// 新增ViewController
UIViewController *viewController3 = [[ThirdViewController alloc] initWithNibName:@"ThirdViewController" bundle:nil];
self.tabBarController = [[UITabBarController alloc] init];
// 将ViewController添加到tabBar中
self.tabBarController.viewControllers = @[viewController1, viewController2, viewController3];
self.window.rootViewController = self.tabBarController;
[self.window makeKeyAndVisible];
return YES;
}

ok，这时如果运行发现我们的TabView已经添加成功了，接下来我们需要修改View3的切换按钮和文字：

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// 按钮文字
self.title = NSLocalizedString(@"Third", @"Third");
// 按钮图片
self.tabBarItem.image = [UIImage imageNamed:@"third"];
}
return self;
}

接下来可以对每个View编写自己的页面和逻辑。