ios开发入门篇（四）：UIWebView结合UISearchBar的简单用法

　　 UIWebView是ios开发中比较常用的一个控件。我们可以用它来浏览网页、打开文档等，今天笔者在这里简单介绍下UIWebView和UISearchBar结合起来的用法，做一个简单的类浏览器。

　　一：首先定义这两个控件，并在.h文件中实现UISearchBarDelegate,UIWebViewDelegate两个代理

　　@interface TestView : UIViewController<UISearchBarDelegate,UIWebViewDelegate>

　　@property(nonatomic)UISearchBar* searchBar;

　@property(nonatomic,retain)UIWebView* webView;

 

　　二：加载这两个控件

//加载searcBar

-(void)initSearchBar

{

    self.searchBar = [[UISearchBar alloc]initWithFrame:CGRectMake(0, 20, [UIScreen mainScreen].bounds.size.width, 40)];

    self.searchBar.delegate = self;             //接受委托

    self.searchBar.text = @"http://";

    //UISearchBar上按钮的默认文字为Cancel，这里改为“GO”版本不同方法有些许区别

    for(id cc in [self.searchBar subviews])

    {

        for (UIView *view in [cc subviews]) {

            if ([NSStringFromClass(view.class) isEqualToString:@"UINavigationButton"])

            {

                UIButton *btn = (UIButton *)view;

                [btn setTitle:@"GO" forState:UIControlStateNormal];

            }

        }

    }

    

    [self.view addSubview:self.searchBar];

    

}

//加载webview

-(void)initWebView

{

    self.webView = [[UIWebView alloc] initWithFrame:CGRectMake(0, 60, [UIScreen mainScreen].bounds.size.width, [UIScreen mainScreen].bounds.size.height-60)];

    [self.webView setUserInteractionEnabled:YES];             //设置是否支持交互

    [self.webView setDelegate:self];                          //接受委托

    [self.webView setScalesPageToFit:YES];                    //设置自动缩放

    [self.view addSubview:self.webView];

}

在viewDidLoad执行加载

-(void)viewDidLoad

{

    [super viewDidLoad];

    [self.view setBackgroundColor:[UIColor whiteColor]];

    [self initSearchBar];

    [self initWebView];

    

}

 　　三：实现seachBar的代理方法

#pragma UISearchBar



//点击searchbar上的GO  时调用

- (void)searchBarCancelButtonClicked:(UISearchBar *)searchBar{

    [self doSearch:searchBar];

}



//点击键盘上的search时调用

- (void)searchBarSearchButtonClicked:(UISearchBar *)searchBar{

    [searchBar resignFirstResponder];

    [self doSearch:searchBar];

}



//开始执行搜索  

- (void)doSearch:(UISearchBar *)searchBar{

    [searchBar resignFirstResponder];

    NSURL* url = [NSURL URLWithString:[NSString stringWithFormat:@"%@",searchBar.text]];

    NSURLRequest *request =[NSURLRequest requestWithURL:url];

    [self.webView loadRequest:request];

}

在这里

　　NSURL* url = [NSURL URLWithString:[NSString stringWithFormat:@"%@",searchBar.text]];

    NSURLRequest *request =[NSURLRequest requestWithURL:url];

    [self.webView loadRequest:request];

这段代码就是为webView加载网页的方式，其他方式的还有

 //加载本地文件资源

//    NSURL *url = [NSURL fileURLWithPath:@"文件路径"]; 

//    NSURLRequest *request = [NSURLRequest requestWithURL:url];

//    [webView loadRequest:request]；

//读入一个HTML代码

//    NSString *htmlPath = [[[NSBundle mainBundle] bundlePath] stringByAppendingPathComponent:@"HTML文件地址"];

//    NSString *htmlString = [NSString stringWithContentsOfFile: htmlPath encoding:NSUTF8StringEncoding error:NULL];

//    [webView loadHTMLString:htmlString baseURL:[NSURL fileURLWithPath:htmlPath]];

四：实现webView加载失败时的代理方法

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

{

    UIAlertView *alterview = [[UIAlertView alloc] initWithTitle:@"访问出错" message:[error localizedDescription]  delegate:nil cancelButtonTitle:nil otherButtonTitles:@"OK", nil];

    [alterview show];

}

另外，UIWebView常用的代理方法还有

- (void )webViewDidStartLoad:(UIWebView  *)webView   

//网页开始加载的时候调用



- (void )webViewDidFinishLoad:(UIWebView  *)webView  

//网页加载完成的时候调用



-(BOOL )webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType )navigationType

//当UIWebView加载网页的时候就会调用到此函数，然后执行webViewDidStartLoad函数，可以在函数中进行请求解析，地址分析等

代码敲完后，来看一下运行的结果