iOS: 计算 UIWebView 的内容高度

先是 html 文件内容

// index.html
<html>
<body>
    <div id="content" contenteditable="false" style="font-family: Helvetica">
        <a href="id:abc" style="text-decoration:none; color:green">
            John
        </a>
        : This is out Rich Text Editing View
    </div>
</body>
</html>

加载 html 文件

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    NSBundle *mainBundle = [NSBundle mainBundle];
    NSURL *indexFileURL = [mainBundle URLForResource:@"index" withExtension:@"html"];
    [self.webView loadRequest:[NSURLRequest requestWithURL:indexFileURL]];
}

计算 webView 显示内容后实际高度

两种方法，方法1可以得到内容的实际高度，方法2得到了将内容显示完整后的 webView 的尺寸（包含 UIEdgeInsets）

- (void)webViewDidFinishLoad:(UIWebView *)wb
{
    //方法1
    CGFloat documentWidth = [[wb stringByEvaluatingJavaScriptFromString:@"document.getElementById('content').offsetWidth"] floatValue];
    CGFloat documentHeight = [[wb stringByEvaluatingJavaScriptFromString:@"document.getElementById(\"content\").offsetHeight;"] floatValue];
    NSLog(@"documentSize = {%f, %f}", documentWidth, documentHeight);
    
    //方法2
    CGRect frame = wb.frame;
    frame.size.width = 768;
    frame.size.height = 1;

//    wb.scrollView.scrollEnabled = NO;
    wb.frame = frame;
    
    frame.size.height = wb.scrollView.contentSize.height;
    
    NSLog(@"frame = %@", [NSValue valueWithCGRect:frame]);
    wb.frame = frame;
}