@interface ViewController ()<UIWebViewDelegate>
@property (weak, nonatomic) IBOutlet UIBarButtonItem backItem;
@property (weak, nonatomic) IBOutlet UIBarButtonItem forwardItem;
@property(nonatomic,weak)UIWebView * webView;


(IBAction)back;
(IBAction)forward;

@end
@implementation ViewController

(void)viewDidLoad {
  [super viewDidLoad];


//1.創建webView
UIWebView * webView = [[UIWebView alloc]init];
webView.frame = self.view.bounds;
self.webView = webView;
[self.view addSubview:webView];
//設置代理
webView.delegate = self;


//2.加載請求
//加載的三種方式，加載三種數據

//《1》加載url請求

//        NSURL  url = [[NSBundle mainBundle]URLForResource:@"login" withExtension:@"html"];
//        NSURLRequest  request = [NSURLRequest requestWithURL:url];
//        [webView loadRequest:request];

//《2》加載html（用于顯示傳遞過來的內容，因為loadHTMLString傳遞的是什么，就顯示什么）(這種方式加載的網頁，不能回退)

//    NSString  path = [[NSBundle mainBundle]pathForResource:@"login.html" ofType:nil];
//    NSString  string = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil];
//    NSLog(@"----%@", string);
//    [webView loadHTMLString:string baseURL:nil];

//《3》加載data數據（可以加載圖片，word，pdf等）（這個方法加載的也不能回退）

//獲取路徑
NSString * path = [[NSBundle mainBundle]pathForResource:@"hell" ofType:@"pdf"];
//獲取mimetype
NSURL * url = [NSURL fileURLWithPath:path];//不要使用urlWithString方法
NSURLRequest * request = [NSURLRequest requestWithURL:url];
NSURLResponse  * rest = nil;
[NSURLConnection  sendSynchronousRequest:request returningResponse:&rest error:nil];//因為需要使用這個返回值，所以使用同步方法
//加載
NSData * data = [NSData dataWithContentsOfFile:path];
[webView loadData:data MIMEType:rest.MIMEType textEncodingName:@"utf8"baseURL:nil];
NSLog(@"MIMEType-----%@",rest.MIMEType);
NSLog(@"%ld",data.length);




}

(IBAction)back{
  [self.webView goBack];//不使用dismiss方法,因為跳轉的不是控制器

}

(IBAction)forward {
  [self.webView goForward];//前進
}

pragma mark - UIWebViewDelegate(四個代理方法)

(void)webViewDidStartLoad:(UIWebView *)webView{
//    NSLog(@"webViewDidStartLoad");

}

(void)webViewDidFinishLoad:(UIWebView *)webView{
  //    if ([webView canGoBack]) {//先判斷這個頁面有沒有返回功能
  //        self.backItem.enabled = YES;
  //    }else{
  //    self.backItem.enabled = NO;
  //    }
//簡便寫法
  NSLog(@"########%i", [webView canGoBack]);
  self.backItem.enabled = [webView canGoBack];
  self.forwardItem.enabled = [webView canGoForward];


}

(void)webView:(UIWebView )webView didFailLoadWithError:(NSError )error{
//    NSLog(@"didFailLoadWithError");
}


(BOOL)webView:(UIWebView )webView shouldStartLoadWithRequest:(NSURLRequest )request navigationType:(UIWebViewNavigationType)navigationType{
  //URL
  //"http://www.baidu.com/&quot;
  //協議頭://主機名//路徑
//過濾掉還有baidu的url
//    NSString * path = request.URL.absoluteString;//注意不是URL.path這個方法，這個方法返回的是“/”
//    NSInteger location = [path rangeOfString:@"baidu"].location;
//    if (location != NSNotFound) {
//        return NO;
//    }
NSLog(@"%@", request.URL.absoluteString);
  return YES;


}
@end
</pre>