Get total height of webView's content using Javascript_问答_开发者

I'm using a UIWebView for displaying content, in the form of an HTML string – not a website, higher than the screen of the iPhone, without needing to scroll in the webView itself, leaving that to the parent scrollView.

To achieve this, I need a way to get the total document size, including the scrollable area, to set the webView's height. I have tried a number of different Javascript solutions:

(document.height !== undefined) ? document.height : document.body.offsetHeight // Returns height of UIWebView
document.body.offsetHeight // Returns zero
document.body.clientHeight // Returns zero
document.documentElement.clientHeight // Returns height of UIWebView
window.innerHeight // Returns height of UIWebView -2
document.body.scrollHeight // Returns zero

Is there a solution that actually works?

Current (nonworking) code:

[[[self.singlePost.contentText subviews] lastObject] setScrollEnabled:NO];
int content_height = [[self.singlePost.contentText stringByEvaluatingJavaScriptFromString: @"document.body.offsetHeight"] intValue];
NSLog(@"Content_height: %d", content_height);
CGRect rect = self.singlePost.cont开发者_C百科entText.frame;
rect.size.height = content_height;
self.singlePost.contentText.frame = rect;

There is no need to use Javascript in iOS 5.0 and up - you have direct, documented access to its scrollView:

- (void)webViewDidFinishLoad:(UIWebView *)webView {
    CGFloat contentHeight = webView.scrollView.contentSize.height;
    // ....
}

To get the total height of the contents of the webView.

When I tried with my code, I found,

(1) NSLog(@"webView height: %@", [webView stringByEvaluatingJavaScriptFromString: @"document.body.offsetHeight"]);
(2) NSLog(@"webView height: %@", [webView stringByEvaluatingJavaScriptFromString: @"document.height"]);

(1) return the height less than the original height. But (2) return the actual height. My suggestion is to get the Max of the two.

- (void)webViewDidFinishLoad:(UIWebView *)theWebView {
    NSLog(@"Body height: %@", [webView stringByEvaluatingJavaScriptFromString: @"document.body.offsetHeight"]);
    NSLog(@"Doc height: %@", [webView stringByEvaluatingJavaScriptFromString: @"document.height"]);
    NSString * javaScript = [NSString stringWithFormat:@"document.getElementById('%@').clientHeight", kDivID];
    NSLog(@"Div height: %@",[webView stringByEvaluatingJavaScriptFromString:javaScript]);
    [self reLayout];
}

- (CGFloat) getWebViewPageHeight {
    CGFloat height1 = [[webView stringByEvaluatingJavaScriptFromString: @"document.height"] floatValue];
    CGFloat height2 = [[webView stringByEvaluatingJavaScriptFromString: @"document.body.offsetHeight"] floatValue]; 
    return MAX(height1, height2);   
}

Output

Body height: 485
Doc height: 509
Div height: 485

Where do you call your code? For me it returns 0 if it is called right after the loadHTMLString Method. If I call it in the (void)webViewDidFinishLoad:(UIWebView *)theWebView delegate, I get a valid value.

- (void)loadHTML: (NSString *)html {
    webView = [[UIWebView alloc] initWithFrame:CGRectMake(0, 0, 100, 100)];
    webView.delegate = self;

    NSURL *resourceURL = [NSURL fileURLWithPath:[[NSBundle mainBundle] bundlePath]];
    [webView loadHTMLString:html baseURL: resourceURL];
    NSLog(@"height: %d", [[webView stringByEvaluatingJavaScriptFromString: @"document.body.offsetHeight"] intValue]); // returns 0
  }

- (void)webViewDidFinishLoad:(UIWebView *)theWebView {
    NSLog(@"height: %@", [webView stringByEvaluatingJavaScriptFromString: @"document.body.offsetHeight"]); //return 2166
}

I went with a slightly different approach, to create a <DIV> that I could key off of to get the size, because I was having no luck with inspecting document/body.

This is MonoTouch C#, but should work fine in Objective-C:

private const string DIV_ID = "_uiwebview_";

LoadHtmlString("<body style='background-color:#yourcolor; padding:0px; margin:0px'>" +
  "<div style='width:" + Frame.Width + "px; padding:0px; margin:0px; font-family:" + 
  font.Name + "' id=" + DIV_ID + ">" + html + "</div></body>", base_url);

and getting the height in LoadFinished:

string sheight = EvaluateJavascript("document.getElementById('" + DIV_ID +
   "').clientHeight");

@Jesse, this works when updating with HTML that would generate a smaller size than was previously shown.

Get total height of webView's content using Javascript

Output

精彩评论

关注公众号

热门标签

图文推荐

Get total height of webView's content using Javascript

Output

更多 问答 相关资讯：

精彩评论

关注公众号

热门标签

图文推荐

更多问答相关资讯：