iOS應用中網絡等待Loading的實現方法

UIWebView加載Loading...兩種方法

第一種方法：使用UIView and UIActivityIndicatorView

//創建UIWebView
WebView = [[UIWebView alloc] initWithFrame:CGRectMake(0, 44, 320, 400)];
[WebView setUserInteractionEnabled:NO];
[WebView setBackgroundColor:[UIColor clearColor]];
[WebView setDelegate:self];
[WebView setOpaque:NO];//使網頁透明

NSString path = @"http://www.baidu.com";
NSURL url = [NSURL URLWithString:path];
[WebView loadRequest:[NSURLRequest requestWithURL:url]];
//創建UIActivityIndicatorView背底半透明View

UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 480)];
[view setTag:103];
[view setBackgroundColor:[UIColor blackColor]];
[view setAlpha:0.8];
[self.view addSubview:view];
activityIndicator = [[UIActivityIndicatorView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 32.0f, 32.0f)];
[activityIndicator setCenter:view.center];
[activityIndicator setActivityIndicatorViewStyle:UIActivityIndicatorViewStyleWhite];
[view addSubview:activityIndicator];
[self.view addSubview:WebView];
[view release];
[WebView release];
//開始加載數據

(void)webViewDidStartLoad:(UIWebView *)webView {    
[activityIndicator startAnimating];         

}

//數據加載完

(void)webViewDidFinishLoad:(UIWebView )webView {
   [activityIndicator stopAnimating];

   UIView view = (UIView *)[self.view viewWithTag:103];
   [view removeFromSuperview];
}
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   第二種方法：使用UIAlertView and UIActivityIndicatorView 
/加載網頁動畫
(void)webViewDidStartLoad:(UIWebView *)webView{
  if (myAlert==nil){

 myAlert = [[UIAlertView alloc] initWithTitle:nil 
                                                        message: @"讀取中..."
                                                          delegate: self
                                           cancelButtonTitle: nil
                                           otherButtonTitles: nil];


UIActivityIndicatorView *activityView = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhite];
   activityView.frame = CGRectMake(120.f, 48.0f, 38.0f, 38.0f);
   [myAlert addSubview:activityView];
   [activityView startAnimating];
   [myAlert show];
   }
}

(void)webViewDidFinishLoad:(UIWebView *)webView{

[myAlert dismissWithClickedButtonIndex:0 animated:YES];

}
</pre>