iPhone SDK - UIWebView has a grey box over it

Question

Sometimes, my UIWebView will have a grey box over part or all of the content. I can\'t make heads or tails of why it\'s happening. It happens regularly for certain content.

Answer 1

I ran into the same issue when dynamically resizing a UIWebView. Here's what worked for me:

#define LAYER_FOR(ui)                        [(ui) layer]
#define FRAME_FOR(ui)                        [LAYER_FOR((ui)) frame]
#define SET_FRAME_FOR(ui, frame)             [LAYER_FOR((ui)) setFrame: (frame)]

+ (void) setHeightTo: (CGFloat *) height_ptr forView: (UIView *) a_view {
  CGFloat height = *height_ptr;

  CGRect existing_frame = [[a_view layer] frame];
  existing_frame.size.height = height;

  // need to reassign the same frame !?
  NSLog(@"setting text view: %@ to height: %f", a_view, (float) height);
  SET_FRAME_FOR(a_view, existing_frame);
}

+ (void) resizeWebView: (UIWebView *) webView {
  NSString *js = @"                                                                                               \
    var __html_element = document.getElementsByTagName('html')[0];                                                \
    var __height_string = document.defaultView.getComputedStyle(__html_element, null).getPropertyValue('height'); \
    __height_string.replace('px', ''); \
  ";

  NSString *heightString = [webView stringByEvaluatingJavaScriptFromString: js];
  float height = [heightString floatValue];

  if (height != UI_VIEW_HEIGHT(webView)) {
    [self setHeightTo: &height forView: webView];

    // resize scrollView inside webview to the same height
    UIScrollView *webScroller = [[webView subviews] lastObject];
    [self setHeightTo: &height forView: webScroller];
  }
}

I called this code from webview's delegate 'webViewDidFinishLoad:' method.

Basically, the trick is to resize the webScroller inside webview.

Thanks to Padraig for the suggestion to nudge the webview's subview (the scrollview).