UI控件---UIWebView

UIWebView是内置浏览器控件，可以用来浏览网页，文档等，今天就试着做一个简易的浏览器！

定义url的初始化方法和返回，前进，刷新三个方法，实现UIWebViewDelegate协议

@interface WebViewController : BaseViewController<UIWebViewDelegate>{

    NSString *_url;
}

-(id)initWithUrl:(NSString*)url;    //创建viewController的时候初始化url
- (IBAction)goBack:(id)sender;      //返回
- (IBAction)goForward:(id)sender;   //前进

- (IBAction)reload:(id)sender;      //刷新
@property (retain, nonatomic) IBOutlet UIWebView *webView;

@end

UIWebView的loadRequest方法可以加载一个url地址，需要把url地址变成NSURLRequest参数

- (void)viewDidLoad
{
    [super viewDidLoad];

    NSURL *url = [NSURL URLWithString:_url];
    NSURLRequest *request = [NSURLRequest requestWithURL:url];
    [_webView loadRequest:request];

    self.title = @"正在加载";

    [UIApplication sharedApplication].networkActivityIndicatorVisible = YES;  //风火轮

}

3个方法的实现

- (IBAction)goBack:(id)sender{

    if ([_webView canGoBack]) {
        [_webView goBack];
    }
}
- (IBAction)goForward:(id)sender{

    if ([_webView canGoForward]) {
        [_webView goForward];
    }

}

- (IBAction)reload:(id)sender{

    [_webView reload];
}

实现协议方法，加载成功和加载失败后调用的方法

#pragma mark - WebView Delegate
- (void)webViewDidFinishLoad:(UIWebView *)webView{

    [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;  //关闭风火轮
    NSString *title = [webView stringByEvaluatingJavaScriptFromString:@"document.title"];//解析JS代码
    self.title = title;

}

- (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error{

    UIAlertView *alterview = [[UIAlertView alloc] initWithTitle:@"" message:[error localizedDescription]  delegate:nil cancelButtonTitle:nil otherButtonTitles:@"OK", nil];
    [alterview show];
    [alterview release];
}

总结：了解了webView所需要的参数，加载过程，以及需要实现的协议方法