calling javascript objective-c without visible uiwebview
Question
I want to call javascript functions from my objective-c. This for iphone. I understand how the call to the javascript function is done with this line
NSString *returnValue = [webView stringByEvaluatingJavascriptFromString:method];
But I dont actually want a webview to be seen or used as part of the UI. So can I just create an instance of it right before calling the method above in some way.
I have tried:
UIWebView *webView = [[UIWebView alloc]initWithFrame:CGRectZero];
[webView loadRequest:[NSUrLRequest requestWithUrl:url]];
but nothing seems to happen. So is there a method similar to the above that I am meant to use.
2 answers
solution1
1 ACCPTED 2013-07-09 10:11:00
add the webview in your controller's view in order to run the javascript. it won't be visible since it has zero height and width.
solution2
0 2013-07-09 10:17:24
Your issue is not related to the size of the UIWebView . It is simply a timing issue. The following code works as desired with a zero rect UIWebView instance. Note the use of UIWebViewDelegate method webViewDidFinishLoad: . UIWebView is slow and it takes time for the view to load its content and be prepared to accept JavaScript commands.
@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:
2013-07-09 03:13:29.347 WebViewTest[14261:c07] The body's inner HTML is: My name
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