ios： webview 中 加载状态显示两种方法

第一种方法：

1. //创建UIWebView  
   
2. WebView = [[UIWebView alloc] initWithFrame:CGRectMake(0, 44, 320, 400)]; 
   
3. [WebView setUserInteractionEnabled:NO]; 
   
4. [WebView setBackgroundColor:[UIColor clearColor]];   
   
5. [WebView setDelegate:self];   
   
6. [WebView setOpaque:NO];//使网页透明  
   
7. 
   
8. NSString *path = @"http://www.baidu.com";  
   
9. NSURL *url = [NSURL URLWithString:path];  
   
10. [WebView loadRequest:[NSURLRequest requestWithURL:url]]; 
    
11. 
    
12. //创建UIActivityIndicatorView背底半透明View   
    
13. UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 480)];  
    
14. [view setTag:103]; 
    
15. [view setBackgroundColor:[UIColor blackColor]];
    
16. [view setAlpha:0.8]; 
    
17. [self.view addSubview:view];  
    
18. 
    
19. activityIndicator = [[UIActivityIndicatorView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 32.0f, 32.0f)]; 
    
20. [activityIndicator setCenter:view.center]; 
    
21. [activityIndicator setActivityIndicatorViewStyle:UIActivityIndicatorViewStyleWhite];   
    
22. [view addSubview:activityIndicator];  
    
23. [self.view addSubview:WebView];   
    
24. [view release]; 
    
25. [WebView release];  
    
26. 
    
27. //以下两个方法是UIWebView的delegate methods
    
28. //开始加载数据
    
29. - (void)webViewDidStartLoad:(UIWebView *)webView { 
    
30.       [activityIndicator startAnimating];   
    
31. } 
    
32. //数据加载完   
    
33. - (void)webViewDidFinishLoad:(UIWebView *)webView {   
    
34.      [activityIndicator stopAnimating];  
    
35.      UIView *view = (UIView *)[self.view viewWithTag:103];   
    
36.      [view removeFromSuperview]; 
    
37. }

第二种方法：在UIAlertView上添加一个UIActivityIndicatorView

1. //加载网页动画 
   
2. - (void)webViewDidStartLoad:(UIWebView *)webView{
   
3.     if (myAlert==nil){ 
   
4.        myAlert = [[UIAlertView alloc] initWithTitle:nil 
   
5.                                                               message: @"正在加载数据，请稍候..."
   
6.                                                                 delegate: self  
   
7.                                                  cancelButtonTitle: nil f
   
8.                                                  otherButtonTitles: nil];
   
9.      UIActivityIndicatorView *activityView = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhite]; 
   
10.      activityView.frame = CGRectMake(120.f, 48.0f, 37.0f, 37.0f);   
    
11.      [myAlert addSubview:activityView]; 
    
12.      [activityView startAnimating]; 
    
13.      [myAlert show]; 
    
14. }
    
15. }
    
16. - (void)webViewDidFinishLoad:(UIWebView *)webView{  
    
17.       [myAlert dismissWithClickedButtonIndex:0 animated:YES]; 
    
18. }