在没有可见的uiwebview的情况下调用javascript Objective-C

Question

I want to call javascript functions from my objective-c. 我想从我的Objective-c调用javascript函数。 This for iphone. 这对于iPhone。 I understand how the call to the javascript function is done with this line 我了解此行如何完成对javascript函数的调用

NSString *returnValue = [webView stringByEvaluatingJavascriptFromString:method];

But I dont actually want a webview to be seen or used as part of the UI. 但我实际上并不希望将Webview视为UI或将其用作UI的一部分。 So can I just create an instance of it right before calling the method above in some way. 因此，我可以以某种方式在调用上述方法之前直接创建它的实例。

I have tried: 我努力了：

UIWebView *webView = [[UIWebView alloc]initWithFrame:CGRectZero];
[webView loadRequest:[NSUrLRequest requestWithUrl:url]];

but nothing seems to happen. 但似乎什么也没发生。 So is there a method similar to the above that I am meant to use. 因此，有没有一种我想要使用的类似于上述方法。

Answer 1

add the webview in your controller's view in order to run the javascript. 在控制器的视图中添加webview以便运行javascript。 it won't be visible since it has zero height and width. 它的高度和宽度为零，因此不可见。

Answer 2

Your issue is not related to the size of the UIWebView . 您的问题与UIWebView的大小无关。 It is simply a timing issue. 这仅仅是一个时间问题。 The following code works as desired with a zero rect UIWebView instance. 以下代码可对零矩形UIWebView实例UIWebView 。 Note the use of UIWebViewDelegate method webViewDidFinishLoad: . 注意，使用UIWebViewDelegate方法webViewDidFinishLoad: UIWebView is slow and it takes time for the view to load its content and be prepared to accept JavaScript commands. UIWebView速度很慢，视图需要花费一些时间来加载其内容并准备接受JavaScript命令。

@interface NGViewController () <UIWebViewDelegate>
@property (nonatomic, strong) UIWebView *hiddenWebView;
@end

@implementation NGViewController

@synthesize hiddenWebView = _hiddenWebView;

- (void)viewWillLayoutSubviews
{
  [super viewWillLayoutSubviews];

  if (!self.hiddenWebView.superview)
  {
    [self.view addSubview:self.hiddenWebView];
  }
}

- (UIWebView *)hiddenWebView
{
  if (!_hiddenWebView) {
    _hiddenWebView = [UIWebView.alloc initWithFrame:CGRectZero];
    _hiddenWebView.delegate = self;
    [_hiddenWebView loadHTMLString:@"<html><head><script>window.james = 'My name';</script></head><body><h1>Hidden Web View by James</h1></body></html>" baseURL:nil];
  }
  return _hiddenWebView;
}

- (void)webViewDidFinishLoad:(UIWebView *)webView
{
  NSString *documentBodyString = [self.hiddenWebView stringByEvaluatingJavaScriptFromString:@"window.james;"];
  NSLog(@"The body's inner HTML is: %@", documentBodyString);
}

@end

The output of which is: 输出为：

2013-07-09 03:13:29.347 WebViewTest[14261:c07] The body's inner HTML is: My name

在没有可见的uiwebview的情况下调用javascript Objective-C

问题描述

2 个解决方案

解决方案1
1 已采纳 2013-07-09 10:11:00

解决方案2
0 2013-07-09 10:17:24

在没有可见的uiwebview的情况下调用javascript Objective-C

问题描述

2 个解决方案

解决方案1 1 已采纳 2013-07-09 10:11:00

解决方案2 0 2013-07-09 10:17:24

解决方案1
1 已采纳 2013-07-09 10:11:00

解决方案2
0 2013-07-09 10:17:24