问在加载Azure登录页面之前，会出现白色屏幕。

EN

-(id) initWithFrame:(CGRect)frame
         client:(MSClient *)client
       startURL:(NSURL *)startURL
         endURL:(NSURL *)endURL
     completion:(MSLoginViewBlock)completion;
{
    self = [super initWithFrame:frame];
    if (self) {
        // Capture all of the initializer values as properties
        client_ = client;
        startURL_ = startURL;
        endURL_ = endURL;
        endURLString_ = endURL_.absoluteString;        
        completion_ = [completion copy];

        // Create the activity indicator and toolbar
       activityIndicator_ = [[UIActivityIndicatorView alloc]
     initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
       activityIndicator_.alpha = 1.0;
       activityIndicator_.center = CGPointMake([[UIScreen mainScreen]bounds].size.width/2, [[UIScreen mainScreen]bounds].size.height/2);
       [self addSubview:activityIndicator_];

       toolbar_ = [self createToolbar:activityIndicator_];
        [self addSubview:toolbar_];

        // Set the toolbar defaults
        showToolbar_ = NO;
        toolbarPosition_ = UIToolbarPositionBottom;

        // Create the webview
        webView_ = [[UIWebView alloc] init];
        [webView_ setOpaque:NO];
        webView_.backgroundColor = [UIColor clearColor];

        webView_.scrollView.scrollEnabled = NO;
        webView_.scrollView.multipleTouchEnabled = NO;
        [webView_.scrollView setBouncesZoom:NO];//disable ZOOM Functionality
        webView_.scalesPageToFit = YES;
        webView_.delegate = self;
        [self addSubview:webView_];
        webView_.hidden =YES;


        // Call setViewFrames to update the subview frames
        [self setViewFrames];

        // Start the first request
        NSURLRequest *firstRequest = [NSURLRequest requestWithURL:startURL];
        [webView_ loadRequest:firstRequest];
    }
    return self;
}