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