UIWebView及加载loading界面

#import <UIKit/UIKit.h>

@interface MainViewController :
UIViewController

{

    UIWebView *webView;

}

#import "MainViewController.h"

@interface
MainViewController ()<UIWebViewDelegate>

@end

@implementation MainViewController

- (void)viewDidLoad {

    [super
viewDidLoad];

    // Do any additional setup after loading the view.

    

    //创建webView

    webView = [[UIWebView
alloc] initWithFrame:CGRectMake(0,
0, 375,
550)];

    webView.delegate =
self;

    NSURLRequest *request = [NSURLRequest
requestWithURL:[NSURL
URLWithString:
@"http://www.baidu.com"]];

    [self.view
addSubview:webView];

    [webView loadRequest:request];

    

}
    //网页开始加载的时候调用

- (void )webViewDidStartLoad:(UIWebView  *)webView

{

    UIView *view = [[UIView
alloc] initWithFrame:CGRectMake(0,
0, 375,
550)];

    [view setTag:108];

    [view setBackgroundColor:[UIColor
blackColor]];

    [view setAlpha:0.5];

    [self.view
addSubview:view];

    

    //loading界面

    UIActivityIndicatorView *activityIndicator = [[UIActivityIndicatorView
alloc]initWithFrame:CGRectMake(0,
0, 32,
32)];

    [activityIndicator setCenter:view.center];

    [activityIndicator setActivityIndicatorViewStyle:UIActivityIndicatorViewStyleWhite];

    [view addSubview:activityIndicator];

    

    [activityIndicator startAnimating];

    

}

    //网页加载完成的时候调用

- (void )webViewDidFinishLoad:(UIWebView  *)webView

{

     UIActivityIndicatorView *activityIndicator = [[UIActivityIndicatorView
alloc]initWithFrame:CGRectMake(0,
0, 32,
32)];

    [activityIndicator stopAnimating];

    UIView *view = (UIView *)[self.view
viewWithTag:108];

    [view removeFromSuperview];

    

}

    //网页加载失败的时候调用

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

{

    UIActivityIndicatorView *activityIndicator = [[UIActivityIndicatorView
alloc]initWithFrame:CGRectMake(0,
0, 32,
32)];

    [activityIndicator stopAnimating];

    UIView *view = (UIView *)[self.view
viewWithTag:108];

    [view removeFromSuperview];

}