本着实践为主的原则,此系列文章不做过多的概念性的阐述和讨论;更多的代码和篇幅用来展示MVC和MVVC下的基础代码结构与具体实现,来展示各自优劣.这篇文章,更多的在于发掘MVC与MVVC的共性,以期为那些对MVVC感兴趣的iOS开发者,找到一种平滑的过渡与重构代码的方式.如果对MVVC感兴趣,可以直接将本文的大部分代码引用到自己的项目中,毕竟代码是写出来的!开篇之前,你可以先到这里下载本文的示例工程: https://github.com/ios122/ios122
在这一篇章里,我会分别使用我所理解的MVC与MVVC两种模式来完成同一个应用场景,以期帮助那些熟悉传统MVC模式代码的iOS攻城狮,能更好理解MVVC.限于篇幅,将MVC和MVVM拆分为两个部分,今天要说的是一个典型的MVC的应用场景,为基于MVC的MVVM重构做个基础.这篇文章着重进行了接口准备,必须的知识点的说明等内容.
我们选取最常见的一组场景: 根据某种规则获取一组数据,点击某一条数据,可以跳转到下一界面获取数据详情.这里我会根据分类请求此分类下的博客列表,点击某一条信息,可跳转到博客详情页.简单说,其实我们真正需要实现的只有两个页面: 博客分类列表页 与 博客详情页.
我们至少需要两个接口,一个可以根据分类来获取博客列表,一个用来根据id获取博客详情.
如果你没有自己的服务器或者对服务器开发不熟悉,可以使用我准备的这两个测试接口:
http://www.ios122.com/find_php/index.php?viewController=YFPostListViewController&model[category]=ui&model[page]=2ui分类名称,目前预定义支持: ui, network, tool,autolayout 四个分类.2,获取第几页的数据,从0开始计数,指请求此分类下第几页的数据.预定义每个分类下有100条数据,每20条数据一页.[ { "id": "ui_40", "title": "title_ui_40", "desc": "desc_ui_40" }, { "id": "ui_41", "title": "title_ui_41", "desc": "desc_ui_41" }, { "id": "ui_42", "title": "title_ui_42", "desc": "desc_ui_42" }, { "id": "ui_43", "title": "title_ui_43", "desc": "desc_ui_43" }, { "id": "ui_44", "title": "title_ui_44", "desc": "desc_ui_44" }, { "id": "ui_45", "title": "title_ui_45", "desc": "desc_ui_45" }, { "id": "ui_46", "title": "title_ui_46", "desc": "desc_ui_46" }, { "id": "ui_47", "title": "title_ui_47", "desc": "desc_ui_47" }, { "id": "ui_48", "title": "title_ui_48", "desc": "desc_ui_48" }, { "id": "ui_49", "title": "title_ui_49", "desc": "desc_ui_49" }, { "id": "ui_50", "title": "title_ui_50", "desc": "desc_ui_50" }, { "id": "ui_51", "title": "title_ui_51", "desc": "desc_ui_51" }, { "id": "ui_52", "title": "title_ui_52", "desc": "desc_ui_52" }, { "id": "ui_53", "title": "title_ui_53", "desc": "desc_ui_53" }, { "id": "ui_54", "title": "title_ui_54", "desc": "desc_ui_54" }, { "id": "ui_55", "title": "title_ui_55", "desc": "desc_ui_55" }, { "id": "ui_56", "title": "title_ui_56", "desc": "desc_ui_56" }, { "id": "ui_57", "title": "title_ui_57", "desc": "desc_ui_57" }, { "id": "ui_58", "title": "title_ui_58", "desc": "desc_ui_58" }, { "id": "ui_59", "title": "title_ui_59", "desc": "desc_ui_59" }]http://www.ios122.com/find_php/index.php?viewController=YFPostViewController&model[id]=ui_0ui_0 表示博客唯一标识.其应为分类博客列表返回的一个有效id.{ "title": "title of ui_0", "body": "<h2>Hello iOS122</h2> Scann To Join Us <br /> <image alt=/"QQ/" src=/"https://raw.githubusercontent.com/ios122/ios122/master/1443002712802.png/" />"}如果你有自己的服务器接口,直接使用即可;但是下面的oc代码,你可能也要对应变换下;如果你对服务器接口开发不是很了解,可以先阅读下这篇文章: iOS程序猿如何快速掌握 PHP,化身”全栈攻城狮”?.
假定,你已经阅读并领会了 << iOS程序猿如何快速掌握 PHP,化身”全栈攻城狮”? >>,这篇文章,新建问及那,并把下面的代码复制到对应文件中,然后根据自己的需要更改即可:
<?php // YFPostListViewController.phpclass YFPostListViewController{ public $model = array(); //!< 传入的数据. PRivate $countOfPerPage = 20; //!< 每页数据条数. /* 获取内容,用于输出显示. */ protected function getContent() { /* 预定义一组数据 */ $datasource = array(); $categorys = array('ui', 'network', 'tool', 'autolayout'); for ($i=0; $i < count($categorys); $i++) { $categoryName = $categorys[$i]; $categoryData = array(); for ($j=0; $j < 100; $j++) { $item = array( 'id' => "{$categoryName}_{$j}", 'title' => "title_{$categoryName}_{$j}", 'desc' => "desc_{$categoryName}_{$j}" ); $categoryData[$j] = $item; } $datasource[$categoryName] = $categoryData; } $queryCategoryName = $this->model['category']; $queryPage = $this->model['page']; $targetCategoryData = $datasource[$queryCategoryName]; $content = array(); for ($i = $this->countOfPerPage * $queryPage ; $i < $this->countOfPerPage * ($queryPage + 1); $i ++ ) { $content[] = $targetCategoryData[$i]; } $content = json_encode($content); return $content; } public function show() { $content = $this->getContent(); header("Content-type: application/json"); echo $content; }}<?php // YFPostViewController.phpclass YFPostViewController{ public $model = array(); //!< 传入的数据. /* 获取内容,用于输出显示. */ protected function getContent() { $id = $this->model['id']; $content = array( 'title' => "title of {$id}", 'body' => '<h2>Hello iOS122</h2> Scann To Join Us <br /> <image alt="qq" src="https://raw.githubusercontent.com/ios122/ios122/master/1443002712802.png" />' ); $content = json_encode($content); return $content; } public function show() { $content = $this->getContent(); header("Content-type: application/json"); echo $content; }}下面列出将要用到的技术点,如有你不熟悉的,可点击对应链接访问:
这一步,大家肯定都会:
YFMVCPostListViewController * mvcPostListVC = [[YFMVCPostListViewController alloc] init]; mvcPostListVC.categoryName = @"ui"; [self.navigationController pushViewController: mvcPostListVC animated: YES];为了保证每次都能进入列表页,都能自动刷新数据,建议在 viewWillAppear:方法刷新数据:
- (void)viewWillAppear:(BOOL)animated{ [super viewWillAppear: animated]; [self updateData];}updateData方法进行数据的更新:
- (void)updateData{ AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager]; NSString * urlStr = [NSString stringWithFormat: @"http://www.ios122.com/find_php/index.php?viewController=YFPostListViewController&model[category]=%@&model[page]=0", self.categoryName]; [manager GET: urlStr parameters:nil success:^(AFHTTPRequestOperation *operation, id responSEObject) { NSLog(@"JSON: %@", responseObject); } failure:^(AFHTTPRequestOperation *operation, NSError *error) { NSLog(@"Error: %@", error); }];}此处使用的是预定义接口,数据请求成功后,控制台输入如下:
JSON: ( { desc = "desc_ui_0"; id = "ui_0"; title = "title_ui_0"; }, { desc = "desc_ui_1"; id = "ui_1"; title = "title_ui_1"; }, { desc = "desc_ui_2"; id = "ui_2"; title = "title_ui_2"; }, { desc = "desc_ui_3"; id = "ui_3"; title = "title_ui_3"; }, { desc = "desc_ui_4"; id = "ui_4"; title = "title_ui_4"; }, { desc = "desc_ui_5"; id = "ui_5"; title = "title_ui_5"; }, { desc = "desc_ui_6"; id = "ui_6"; title = "title_ui_6"; }, { desc = "desc_ui_7"; id = "ui_7"; title = "title_ui_7"; }, { desc = "desc_ui_8"; id = "ui_8"; title = "title_ui_8"; }, { desc = "desc_ui_9"; id = "ui_9"; title = "title_ui_9"; }, { desc = "desc_ui_10"; id = "ui_10"; title = "title_ui_10"; }, { desc = "desc_ui_11"; id = "ui_11"; title = "title_ui_11"; }, { desc = "desc_ui_12"; id = "ui_12"; title = "title_ui_12"; }, { desc = "desc_ui_13"; id = "ui_13"; title = "title_ui_13"; }, { desc = "desc_ui_14"; id = "ui_14"; title = "title_ui_14"; }, { desc = "desc_ui_15"; id = "ui_15"; title = "title_ui_15"; }, { desc = "desc_ui_16"; id = "ui_16"; title = "title_ui_16"; }, { desc = "desc_ui_17"; id = "ui_17"; title = "title_ui_17"; }, { desc = "desc_ui_18"; id = "ui_18"; title = "title_ui_18"; }, { desc = "desc_ui_19"; id = "ui_19"; title = "title_ui_19"; })这一部分,涉及的变动较多,我就直接贴代码了.你会注意到View和数据已经交叉进行了,很乱的感觉.而这也是我们想要使用MVVM重构代码的重要原因之一.
//// YFMVCPostListViewController.m// iOS122//// Created by 颜风 on 15/10/14.// Copyright (c) 2015年 iOS122. All rights reserved.//#import "YFMVCPostListViewController.h"#import "YFArticleModel.h"#import <AFNetworking.h>#import <MJRefresh.h>#import <MBProgressHUD.h>@interface YFMVCPostListViewController ()<UITableViewDelegate, UITableViewDataSource>@property (nonatomic, strong) UITableView * tableView;@property (nonatomic, strong) NSMutableArray * articles; //!< 文章数组,内部存储AFArticleModel类型.@property (assign, nonatomic) NSInteger page; //!< 数据页数.表示下次请求第几页的数据.@end@implementation YFMVCPostListViewController- (void)viewDidLoad { [super viewDidLoad]; // Do any additional setup after loading the view.}- (NSMutableArray *)articles{ if (nil == _articles) { _articles = [NSMutableArray arrayWithCapacity: 42]; } return _articles;}- (void)didReceiveMemoryWarning { [super didReceiveMemoryWarning]; // Dispose of any resources that can be recreated.}- (void)viewWillAppear:(BOOL)animated{ [super viewWillAppear: animated]; // 马上进入刷新状态 [self.tableView.header beginRefreshing];}- (UITableView *)tableView{ if (nil == _tableView) { _tableView = [[UITableView alloc] init]; [self.view addSubview: _tableView]; [_tableView makeConstraints:^(MASConstraintMaker *make) { make.edges.equalTo(UIEdgeInsetsMake(0, 0, 0, 0)); }]; _tableView.delegate = self; _tableView.dataSource = self; NSString * cellReuseIdentifier = NSStringFromClass([UITableViewCell class]); [_tableView registerClass: NSClassFromString(cellReuseIdentifier) forCellReuseIdentifier:cellReuseIdentifier]; _tableView.header = [MJRefreshNormalHeader headerWithRefreshingBlock:^{ self.page = 0; [self updateData]; }]; _tableView.footer = [MJRefreshBackNormalFooter footerWithRefreshingBlock:^{ [self updateData]; }]; } return _tableView;}/** * 更新视图. */- (void) updateView{ [self.tableView reloadData];}/** * 更新数据. * * 数据更新后,会自动更新视图. */- (void)updateData{ AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager]; NSString * urlStr = [NSString stringWithFormat: @"http://www.ios122.com/find_php/index.php?viewController=YFPostListViewController&model[category]=%@&model[page]=%ld", self.categoryName, (long)self.page ++]; [manager GET: urlStr parameters:nil success:^(AFHTTPRequestOperation *operation, id responseObject) { [self.tableView.header endRefreshing]; [self.tableView.footer endRefreshing]; if (1 == self.page) { // 说明是在重新请求数据. self.articles = nil; } NSArray * responseArticles = [YFArticleModel objectArrayWithKeyValuesArray: responseObject]; [self.articles addObjectsFromArray: responseArticles]; [self updateView]; } failure:^(AFHTTPRequestOperation *operation, NSError *error) { [self.tableView.header endRefreshing]; [self.tableView.footer endRefreshing]; MBProgressHUD *hud = [MBProgressHUD showHUDAddedTo:self.view animated:YES]; hud.mode = MBProgressHUDModeText; hud.labelText = @"您的网络不给力!"; [hud hide: YES afterDelay: 2]; }];}# pragma mark - tabelView代理方法.- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{ NSInteger number = self.articles.count; return number;}- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{ NSString * cellReuseIdentifier = NSStringFromClass([UITableViewCell class]); UITableViewCell * cell = [tableView dequeueReusableCellWithIdentifier: cellReuseIdentifier forIndexPath:indexPath]; YFArticleModel * model = self.articles[indexPath.row]; NSString * content = [NSString stringWithFormat: @"标题:%@ 内容:%@", model.title, model.desc]; cell.textLabel.text = content; return cell;}@end只需要再额外实现下 -tableView: didSelectRowAtIndexPath:方法即可:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{ // 跳转到博客详情. YFArticleModel * articleModel = self.articles[indexPath.row]; YFMVCPostViewController * postVC = [[YFMVCPostViewController alloc] init]; postVC.articleID = articleModel.id; [self.navigationController pushViewController: postVC animated: YES];}
这里其实就是博客列表的控制器的那几句:
// 跳转到博客详情.YFArticleModel * articleModel = self.articles[indexPath.row]; YFMVCPostViewController * postVC = [[YFMVCPostViewController alloc] init]; postVC.articleID = articleModel.id; [self.navigationController pushViewController: postVC animated: YES];此处为了方便,我们依然使用预定义的博客详情接口:
AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager]; NSString * urlStr = [NSString stringWithFormat: @"http://www.ios122.com/find_php/index.php?viewController=YFPostViewController&model[id]=%@", self.articleID]; [manager GET: urlStr parameters:nil success:^(AFHTTPRequestOperation *operation, id responseObject) { NSLog(@"%@", responseObject); [self updateView]; } failure:^(AFHTTPRequestOperation *operation, NSError *error) { MBProgressHUD *hud = [MBProgressHUD showHUDAddedTo:self.view animated:YES]; hud.mode = MBProgressHUDModeText; hud.labelText = @"您的网络不给力!"; [hud hide: YES afterDelay: 2]; }];请求的输入,Xcode控制台打印输出,类似于:
{ body = "<h2>Hello iOS122</h2> Scann To Join Us <br /> <image alt=/"qq/" src=/"https://raw.githubusercontent.com/ios122/ios122/master/1443002712802.png/" />"; title = "title of ui_0";}你会注意到,我们在上一步获取的数据,body部分内部是HTML字符串,所以我们要使用webView来显示博客详情.这和最近炒得很火的的混合开发模式有些像,但是目前主流的博客应用,几乎都是这么做的.完整代码如下:
//// YFMVCPostViewController.m// iOS122//// Created by 颜风 on 15/10/16.// Copyright (c) 2015年 iOS122. All rights reserved.//#import "YFMVCPostViewController.h"#import "YFArticleModel.h"#import <AFNetworking.h>#import <MBProgressHUD.h>@interface YFMVCPostViewController ()<UIWebViewDelegate>@property (strong, nonatomic) UIWebView * webView;@property (strong, nonatomic) YFArticleModel * article;@end@implementation YFMVCPostViewController- (UIWebView *)webView{ if (nil == _webView) { _webView = [[UIWebView alloc] init]; [self.view addSubview: _webView]; [_webView makeConstraints:^(MASConstraintMaker *make) { make.edges.equalTo(UIEdgeInsetsMake(64, 0, 0, 0)); }]; } return _webView;}- (void)viewDidLoad { [super viewDidLoad]; // Do any additional setup after loading the view.}- (void)didReceiveMemoryWarning { [super didReceiveMemoryWarning]; // Dispose of any resources that can be recreated.}- (void)viewWillAppear:(BOOL)animated{ [super viewWillAppear: animated]; [self updateData];}/** * 更新视图. */- (void) updateView{ [self.webView loaDHTMLString: self.article.body baseURL:nil];}/** * 更新数据. * * 数据更新后,会自动更新视图. */- (void)updateData{ [MBProgressHUD showHUDAddedTo:self.view animated: YES]; AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager]; NSString * urlStr = [NSString stringWithFormat: @"http://www.ios122.com/find_php/index.php?viewController=YFPostViewController&model[id]=%@", self.articleID]; [manager GET: urlStr parameters:nil success:^(AFHTTPRequestOperation *operation, id responseObject) { self.article = [YFArticleModel objectWithKeyValues: responseObject]; [self updateView]; } failure:^(AFHTTPRequestOperation *operation, NSError *error) { MBProgressHUD *hud = [MBProgressHUD showHUDAddedTo:self.view animated:YES]; hud.mode = MBProgressHUDModeText; hud.labelText = @"您的网络不给力!"; [hud hide: YES afterDelay: 2]; }];}@end此篇主要展示了一个典型的列表-->详情场景的MVC实现,相关技术代码可以直接用于自己的项目中.尽管这是简化的场景,但依然可以很明显地看出来数据,网络请求与视图间的相互调用,使代码整体的可复用性大大降低! 而这,也是我们下次要用 MVVC 重构这个示例的核心目的之一!
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