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

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    //1.創建遠程NSURL對象;指定請求的url
    NSURL *url = [NSURL URLWithString:@"http://www.baidu.com"];
    //2.創建NSURLRequest對象
    NSURLRequest *request = [NSURLRequest requestWithURL:url];
    //2.1 設置代理
    self.webView.delegate = self;
    //3.使用webView對象加載請求
    [self.webView loadRequest:request];
}

//開始加載
- (void)webViewDidStartLoad:(UIWebView *)webView {
    [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:YES];
}
//成功加載完畢
- (void)webViewDidFinishLoad:(UIWebView *)webView {
    [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:NO];
}
//失敗返回
- (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error {
    [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:NO];
    NSLog(@"請求百度主頁失敗:%@", error.userInfo);
}

@end

//在Info.plist中添加下面代碼
Allow Arbitrary Loads    YES