Handle Javascript onclick function in Objective-C

Question

I have a button inside a web view.
When the button is clicked, I would like to add the item to my native code array.
Then, when it's pressed again, I would like to remove the item in the array.

My question is: What's missing in the logic? Neither userContentController or decidePolicyForNavigationAction is called when the button is pressed.

The JavaScript Code

<script type = "text/javascript">
 function someFunction(id) {
  if(id = true) {
    document.getELementById("someid").innerText = " some title state 1"
  } else {
     document.getELementById(someid).innerText = " some title state 2"
  }
 }
<script>

The Html Button

<button class=someclass id="someid" onclick= "Some.listCallBack()">Add List</button>

The Objective C code

TableViewCell.h
@interface TableViewCell : UITableViewCell <WKNavigationDelegate, WKScriptMessageHandler>
@property (nonatomic,strong) IBOutlet WKWebView *webView;
 
TableViewCell.m

- (void)awakeFromNib {
 [[[self.webView configuration] userContentController]addScriptMessageHandler:selfname:@"someid"];
}

- (void)userContentController:(nonnull WKUserContentController *)userContentController 
didReceiveScriptMessage:(nonnull WKScriptMessage *)message {
// i will handle event here 

}

What’s Some.listCallback()? Whatever is missing (or isn’t missing) seems to be in there. — K Lee
– K Lee, Commented Mar 29, 2020 at 1:12

K Lee · Accepted Answer · 2020-03-29 01:49:20Z

1

Since the actual click handler seems to be omitted from the question, it’s hard to tell what the exact problem is. I might therefore be stating the obvious, but here we go.

The handler (the one registered with -addScriptMessageHandler:name:) is exposed to JavaScript as a property on webkit.messageHandlers. From there, the interprocess communication looks more or less like messaging another window, except instead of window.postMessage() we use webkit.messageHandlers.handlerID.postMessage(). In other words,

function clickHandler() {
    webkit.messageHandlers.someid.postMessage("The message we’d like to pass to our WKScriptMessageHandler");
}

should do.

answered Mar 29, 2020 at 1:49

K Lee

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