置顶] iOS中 UIWebView加载网络数据 技术分享

[置顶] iOS中 UIWebView加载网络数据 技术分享 

直奔核心:

 #import "TechnologyDetailViewController.h"
 #define kScreenWidth [UIScreen mainScreen].bounds.size.width
 #define kScreenHeight [UIScreen mainScreen].bounds.size.height
 @interface TechnologyDetailViewController ()
 @property (nonatomic,retain)UIWebView *webView;//显示详情页面
 @end

 @implementation TechnologyDetailViewController
 - (void)dealloc
 {
     self.webView = nil;
     self.ids = nil;
     [super dealloc];
 }

 - (void)viewDidLoad {
     [super viewDidLoad];
     //设置背景
     self.view.backgroundColor = [UIColor yellowColor];
     //调用请求网络数据
     [self readDataFromNetWork];
     //    self.automaticallyAdjustsScrollViewInsets = NO;
     [self.view addSubview:self.webView];
 }

懒加载UIWebView

 //懒加载
 - (UIWebView *)webView{
     if (!_webView) {
         self.webView = [[[UIWebView alloc]initWithFrame:CGRectMake(0,0, [UIScreen mainScreen].bounds.size.width, [UIScreen mainScreen].bounds.size.height)]autorelease];
         self.webView.backgroundColor = [UIColor orangeColor];

     }
     return [[_webView retain ]autorelease];
 }

核心代码如下:

 //解析数据
 - (void)readDataFromNetWork{
     NSString *str = [NSString stringWithFormat:@"http://c.3g.163.com/nc/article/%@/full.html",self.ids];
     NSURL *url = [NSURL URLWithString:str];
     NSURLRequest *request = [NSURLRequest requestWithURL:url];
     [NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {
         NSDictionary *dic = [NSJSONSerialization JSONObjectWithData:data options:0 error:nil];


         NSString *body = dic[self.ids][@"body"];
         NSString * title = dic[self.ids][@"title"];
         NSString *digest = dic[self.ids][@"digest"];
         NSString *ptime = dic[self.ids][@"ptime"];
         NSString * source = dic[self.ids][@"source"];
         NSArray * img = dic[self.ids][@"img" ] ;
         //        NSLog(@"%@",img);
         if (img.count) {
             for (int i = 0; i < img.count; i ++) {


                 NSString *imgString = [NSString stringWithFormat:@"<p style=\"text-align:center\"><img src=\"%@\" /></p>",img[i][@"src"]];
                 NSLog(@"imString  = %@",imgString);

                 imgString = [imgString stringByReplacingOccurrencesOfString:@"<!--IMG#%d-->" withString:imgString];
                 body = [imgString stringByAppendingString:body];


             }
         }
         //        NSLog(@"body =  %@",body);

         //借助第三方进行排版
         NSString *filePath = [[NSBundle mainBundle]pathForResource:@"topic_template" ofType:@"html"];
         NSString *htmlString = [NSString stringWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:nil];

         htmlString = [htmlString stringByReplacingOccurrencesOfString:@"__BODY__" withString:body];
         htmlString = [htmlString stringByReplacingOccurrencesOfString:@"__TITLE__" withString:title];
         htmlString = [htmlString stringByReplacingOccurrencesOfString:@"__AUTHOR__" withString:source];
         htmlString = [htmlString stringByReplacingOccurrencesOfString:@"__DIGEST__" withString:digest];
         htmlString = [htmlString stringByReplacingOccurrencesOfString:@"__TIME__" withString:ptime];
         htmlString = [htmlString stringByReplacingOccurrencesOfString:@"__PTIME__" withString:ptime];
         [self.webView loadHTMLString:htmlString baseURL:nil];


     }];

 }

======================================================================================================

实在看不懂再看下demol例子:

UIWebView的loadRequest可以用来加载一个url地址，它需要一个NSURLRequest参数。我们定义一个方法用来加载url。在UIWebViewDemoViewController中定义下面方法：

 - (void)loadWebPageWithString:(NSString*)urlString
 {
     NSURL *url =[NSURL URLWithString:urlString];
     NSLog(urlString);
     NSURLRequest *request =[NSURLRequest requestWithURL:url];
     [webView loadRequest:request];
 }

在界面上放置3个控件，一个textfield、一个button、一个uiwebview，布局如下：

在代码中定义相关的控件：webView用于展示网页、textField用于地址栏、activityIndicatorView用于加载的动画、buttonPress用于按钮的点击事件。

 @interface UIWebViewDemoViewController :UIViewController<UIWebViewDelegate> {
     IBOutlet UIWebView *webView;
     IBOutlet UITextField *textField;
     UIActivityIndicatorView *activityIndicatorView;

 }
 - (IBAction)buttonPress:(id) sender;
 - (void)loadWebPageWithString:(NSString*)urlString;
 @end

使用IB关联他们。

设置UIWebView，初始化UIActivityIndicatorView：

 - (void)viewDidLoad
 {
     [super viewDidLoad];
     webView.scalesPageToFit =YES;
     webView.delegate =self;
     activityIndicatorView = [[UIActivityIndicatorView alloc]
                              initWithFrame : CGRectMake(0.0f, 0.0f, 32.0f, 32.0f)] ;
     [activityIndicatorView setCenter: self.view.center] ;
     [activityIndicatorView setActivityIndicatorViewStyle: UIActivityIndicatorViewStyleWhite] ;
     [self.view addSubview : activityIndicatorView] ;
     [self buttonPress:nil];
     // Do any additional setup after loading the view from its nib.
 }

UIWebView主要有下面几个委托方法：

1、- (void)webViewDidStartLoad:(UIWebView *)webView;开始加载的时候执行该方法。
2、- (void)webViewDidFinishLoad:(UIWebView *)webView;加载完成的时候执行该方法。
3、- (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error;加载出错的时候执行该方法。

我们可以将activityIndicatorView放置到前面两个委托方法中。

 - (void)webViewDidStartLoad:(UIWebView *)webView
 {
     [activityIndicatorView startAnimating] ;
 }
 - (void)webViewDidFinishLoad:(UIWebView *)webView
 {
     [activityIndicatorView stopAnimating];
 }

buttonPress方法很简单，调用我们开始定义好的loadWebPageWithString方法就行了：

 - (IBAction)buttonPress:(id) sender
 {
     [textField resignFirstResponder];
     [self loadWebPageWithString:textField.text];

 }

当请求页面出现错误的时候，我们给予提示：

 - (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error
 {
     UIAlertView *alterview = [[UIAlertView alloc] initWithTitle:@"" message:[error localizedDescription]  delegate:nil cancelButtonTitle:nil otherButtonTitles:@"OK", nil nil];
     [alterview show];
     [alterview release];
 }

总结：本文通过实现一个简单的浏览器，说明了uiwebview的方法和属性，相信通过这个例子，应该明白uiwebview的使用了。