javascript - 如何判断 stringByEvaluatingJavaScriptFromString 求值过程完成？

Question

我正在将 html 文件读入 UIWebview。在 webViewDidFinishLoad 中，我正在为水平滚动执行 javascript 函数。下面的代码工作正常。但我无法预测 javascript 函数何时完成。

在可见的 webview 中首先加载 html 文件然后脚本运行。所以我可以确定 javascript 在 webViewDidFinishLoad 中完成。

- (void)webViewDidFinishLoad:(UIWebView *)webView
{

    NSString *scriptString =@"javascript:function initialize() {  var eelam = document.getElementsByTagName('body')[0]; var ourH = window.innerHeight;var ourW = window.innerWidth;  var fullH = eelam.offsetHeight;  var pageCount = Math.ceil(fullH/ourH)+1; var padval = parseInt((screen.width*10)/100);var currentPage = 0; var newW = pageCount*ourW;eelam.style.height = (ourH - 30)+'px';eelam.style.width = (newW)+'px';eelam.style.webkitColumnGap = '5px'; eelam.style.margin = '25px'; eelam.style['margin-left']='2px';eelam.style.webkitColumnCount = pageCount; window.interface.setPageCount(pageCount);window.interface.setColumnWidth(screen.width);window.interface.setContent(eelam);window.interface.setColumnGap(padval);};";

    // set font
    NSString *jsString = [[NSString alloc] initWithFormat:@"document.getElementsByTagName('body')[0].style.webkitTextSizeAdjust= '%d%%'",
                          textFontSize];

    [mywebview stringByEvaluatingJavaScriptFromString:scriptString];

    [mywebview stringByEvaluatingJavaScriptFromString:@"javascript:initialize()"];

    [mywebview stringByEvaluatingJavaScriptFromString:jsString];

    // scroll disable
    UIView* row = nil;
    for(row in webView.subviews){
        if([row isKindOfClass:[UIScrollView class] ]){
            UIScrollView* scrollRow = (UIScrollView*) row;
            scrollRow.scrollEnabled = NO;
            scrollRow.bounces = NO;
            scrollRow.pagingEnabled=YES;
        }
    }

// this code is also not use to handle my issue
if ([[mywebview stringByEvaluatingJavaScriptFromString:@"document.readyState"] isEqualToString:@"complete"]) {

       }


}

请多多指教

提前致谢，

Answer 1

该函数不是异步的。它在从评估函数返回值之前完成。