How to detect UIWebview drop in iOS 11?

Question

I have a UIWebView. I am trying to implement ios11 drag and drop feature. When I drag item from Safari and drop it in my UIWebView, I want to know which delegate method will get called. Any suggestions?

Answer 1

Most of the functionality of UIWebview is implemented in an undocumented class called UIWebBrowserView. It is that view which has its 'interactions' property set and the delegate for those interactions is set to that same UIWebBrowserView.

Depending on your needs, there are 3 options to detect the drop:

1) You could use javascript in the content of the web view to detect the drop. This would looks something like:

document.addEventListener('drop', function() {
     // Drop detected
} ) ;

2) You could disable the drop interactions in the UIWebBrowserView. That will allow them to propagate up into one of the containing views, and you can add your own interactions there. That would look like:

webView.scrollView.subviews[0].interactions = @[] ;  

Once you've done that, the you can create your own interactions and add them to the container view:

 UIDropInteraction *dropInteration = [[UIDropInteraction alloc]initWithDelegate:myController] ;
 [webView addInteraction:dropInteration] ;
 webView.userInteractionEnabled = YES ;

You would then implement the UIDropInteractionDelegate functionality in 'myController'

3) You could swizzle UIWebBrowserView and replace the UIDropInteractionDelegate methods with your own.

Answer 2

UIDragInteractionDelegate & UIDropInteractionDelegate protocols are what you're looking for.

Check this out as well: How to Drop Images in UIViewController with UIDropInteraction (Ep 1)