Call objective-c method from javascript

Question

I make any webView And I want to call from javascript any objective c method which return any parameter. I tried many ways but not allowed . Objective c method here:

- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType
{
    NSURL *URL = [request URL];
    if ([[URL scheme] isEqualToString:@"donordialog"])
    {
        // now we need to figure out the function part
        NSString *functionString = [URL resourceSpecifier];

        if ([functionString hasPrefix:@"bloodTypeChanged"])
        {
            // the blood type has changed, now do something about it.
            NSString *parameter = [functionString stringByReplacingOccurrencesOfString:@"bloodTypeChanged" withString:@""];

            // remove the '(' and then the ')'
            parameter = [parameter stringByReplacingOccurrencesOfString:@"(" withString:@""];
            parameter = [parameter stringByReplacingOccurrencesOfString:@")" withString:@""];

            // log the paramter, as I don't know what to do with it right now
            UIAlertView *alert=[[ UIAlertView alloc] initWithTitle:@"iosdan javascripti"
                                                                           message:@"ddddddddd"
                                                                    delegate:nil
                                                                cancelButtonTitle:@"OK"
                                                               otherButtonTitles:nil];

            [alert show];
            //NSLog(@"%@", parameter);
        }

        return NO;
    }

    return YES;
}

javascript:

function myFunction() {
    url="http://example.com";
    window.location="donordialog:blooTypeChanged("+url+")";
}

html:

<button onclick="myFunction()">click me</button>

comment: I need that: it is obj c method for example. aaa{} . My aaa method must return any parameter. and I have wevView. I loaded any url to this webView: for example www.example.com/forios . I need call this (aaa) method from javascript which it is in html on www.example.com/forios and alert the result of aaa function. understand?. If understand, dont watch to my code. help please yourself anyway. android version of my question:Call Java function from JavaScript over Android WebView I want to alert some parameter returning from method. Help please. Thanks.

Nothing to archieve. I want to alert any parameter witch returning from obj c method in WebView. İ tried all answers from stack and others. But not success. — Mehman Bashirov
– Mehman Bashirov, Commented Feb 21, 2014 at 7:17
When do you call myFunction()? Also just so you know it really isn't clear exactly what you want I had to read it a couple of times to fully understand, and I should have to do that it should be clear from the get go. — Popeye
– Popeye, Commented Feb 21, 2014 at 8:26
@Popeye on any button click. I need that: it is obj c method for example. aaa{} . My aaa method must return any parameter. and I have wevView. I loaded any url to this webView: for example www.example.com/forios . I need call this (aaa) method from javascript which it is in html on www.example.com/forios and alert the result of aaa function. :'( understand?. If understand, dont watch to my code. help please yourself anyway. — Mehman Bashirov
– Mehman Bashirov, Commented Feb 21, 2014 at 8:45

Fusion Radio Dev · Accepted Answer · 2014-08-23 18:58:54Z

Here is a quick and easy solution without JavaScriptCore for backwards compatibility (might consider upgrading to Javascriptcore ). Here's an easy implementation.

Note: this solution is for UIwebview only (not UIscrollview)

//viewcontroller.h

@interface ViewController : UIViewController<UIWebViewDelegate>

@property (strong, nonatomic) IBOutlet UIWebView *viewWeb;
@end

//viewcontroller.m

- (void)viewDidLoad
{
    [super viewDidLoad];


    NSString *fullURL = @"http:player.fusion.fm";
    NSURL *url = [NSURL URLWithString:fullURL];
    NSURLRequest *requestObj = [NSURLRequest requestWithURL:url];
    [_viewWeb loadRequest:requestObj];
   _viewWeb.delegate = self;
 }

 -(BOOL)webView:(UIWebView *)_viewWeb shouldStartLoadWithRequest:(NSURLRequest *)request   navigationType:(UIWebViewNavigationType)navigationType {
    NSURL *url = request.URL;
    if ([[url scheme] isEqualToString:@"ios"])
    {
        [self mute]; // <-- YOUR OBJ-C FUNCTION HERE
        NSLog(@"test");
        return YES;
    }else
     {
        return YES;
    }

 }

// The Javascript (within webview)

try
{
  window.location="ios://null"
}
catch(err)
{
}

Source: http://adoptioncurve.net/archives/2012/09/calling-objective-c-methods-from-javascript-in-a-uiwebview/

Mykola Denysyuk · Accepted Answer · 2014-02-21 09:37:23Z

2

The most usual approach that I used to interact from javascript within obj-c is to changing hash. On required event in your js write window.location.hash = '#cmd_alertMessage'; after this your - (BOOL)webView: shouldStartLoadWithRequest: navigationType: will be called:

   - (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType
{
    NSArray * compenents = [request.URL.absoluteString componentsSeparatedByString:@"#"];
    if (compenents.count > 1) {
        NSString * cmd = compenents[1];
        if ([cmd rangeOfString:@"cmd_alertMessage"].location != NSNotFound) {
            // Call your obj-c method and get appropriated param
            NSString * jsFunction = [NSString stringWithFormat:@"setParameterFromAAAMethod('%@')", [self aaa]];
            // Return this param back to js
            NSString * alertMessage = [webView stringByEvaluatingJavaScriptFromString:jsFunction];
        }
    }


    return YES;
}

- (NSString *)aaa
{
    return @"This is special parameter that you need";
}

So, it will work in 3 steps:

Invoke hash changing to request parameter from obj-c code in js;
Handle hash changed (parameter request) and return in back to js in obj-c;
Handle recieved parameter in js again

edited Feb 21, 2014 at 9:37

answered Feb 21, 2014 at 8:44

Mykola Denysyuk

2,0031 gold badge16 silver badges15 bronze badges

12 Comments

Mehman Bashirov Over a year ago

error:No visible interface for 'NSString' declares the selector 'isContainString'

Mehman Bashirov Over a year ago

Thanks for answer. but I want vise versa. I did that o android. android version of my question:stackoverflow.com/questions/10389572/…

Mehman Bashirov Over a year ago

you undertand my question right . How I'll alert this param in javascript? Full write please.

Mykola Denysyuk Over a year ago

I'm not really familiar with js, but: function setParameterFromAAAMethod(parameter) { alert(parameter); }

Mehman Bashirov Over a year ago

not called. Please check your answer again. please please. I'm in difficulty.

|

Janis Kirsteins · Accepted Answer · 2014-02-21 08:39:34Z

1

You can set a hidden iframe's location to something specific to your app, and then intercept that request in Obj-C.

Here's an overview and some examples: http://blog.techno-barje.fr//post/2010/10/06/UIWebView-secrets-part3-How-to-properly-call-ObjectiveC-from-Javascript/

answered Feb 21, 2014 at 8:39

Janis Kirsteins

2,14816 silver badges17 bronze badges

Comments

Piyush Dubey · Accepted Answer · 2014-02-21 07:22:52Z

0

Well, I am not sure whether I got your question correct or not, but if you want to call any javascript method, then you can do this way:-

[yourWebView stringByEvaluatingJavaScriptFromString:@"yourMethodName()"];

You can also pass parameters in above method.

answered Feb 21, 2014 at 7:22

Piyush Dubey

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2 Comments

Mehman Bashirov Over a year ago

Thanks for answer. But I want vise versa. I mean, write any method in obj c, whitch return any string or int parameter. And alert this parameter in javascript (webview). call this method from javascript whitch included to webview.

Mehman Bashirov Over a year ago

android version of my question:stackoverflow.com/questions/10389572/…

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