CODEWITHSUNDEEP
javascripthtmlioswebview
Soumya Ranjan
Soumya Ranjan

Reputation: 4843

How to call a Javascript method in iOS?

<html>
<head>
<script type="text/javascript" src="js/jquery.js"></script>
<script type="text/javascript" src="js/quiz-1.js"></script>
<link rel="stylesheet" type="text/css" href="style.css" />
</head>
<body>
<p class="question">1. What is the answer to this question?</p>        

<ul class="answers">            
<input type="radio" name="q1" value="a" id="q1a"><label for="q1a">Answer 1</label><br/>          
<input type="radio" name="q1" value="b" id="q1b"><label for="q1b">Answer 2</label><br/>            
<input type="radio" name="q1" value="c" id="q1c"><label for="q1c">Answer 3</label><br/>            
<input type="radio" name="q1" value="d" id="q1d"><label for="q1d">Answer 4</label><br/>       
</ul>        


<p class="question">2. What is the answer to this question?</p>        

<ul class="answers">            
<input type="radio" name="q2" value="a" id="q2a"><label for="q2a">Answer 1</label><br/>           
<input type="radio" name="q2" value="b" id="q2b"><label for="q2b">Answer 2</label><br/>            
<input type="radio" name="q2" value="c" id="q2c"><label for="q2c">Answer 3</label><br/>           
<input type="radio" name="q2" value="d" id="q2d"><label for="q2d">Answer 4</label><br/>       
</ul>        

<p class="question">3. What is the answer to this question?</p>        

<ul class="answers">            
<input type="radio" name="q3" value="a" id="q3a"><label for="q3a">Answer 1</label><br/>            
<input type="radio" name="q3" value="b" id="q3b"><label for="q3b">Answer 2</label><br/>            
<input type="radio" name="q3" value="c" id="q3c"><label for="q3c">Answer 3</label><br/>           
<input type="radio" name="q3" value="d" id="q3d"><label for="q3d">Answer 4</label><br/>       
</ul>        

<p class="question">4. What is the answer to this question?</p>        

<ul class="answers">           
<input type="radio" name="q4" value="a" id="q4a"><label for="q4a">Answer 1</label><br/>            
<input type="radio" name="q4" value="b" id="q4b"><label for="q4b">Answer 2</label><br/>            
<input type="radio" name="q4" value="c" id="q4c"><label for="q4c">Answer 3</label><br/>            
<input type="radio" name="q4" value="d" id="q4d"><label for="q4d">Answer 4</label><br/>        
</ul>        

<p class="question">5. What is the answer to this question?</p>        

<ul class="answers">            
<input type="radio" name="q5" value="a" id="q5a"><label for="q5a">Answer 1</label><br/>            
<input type="radio" name="q5" value="b" id="q5b"><label for="q5b">Answer 2</label><br/>            
<input type="radio" name="q5" value="c" id="q5c"><label for="q5c">Answer 3</label><br/>           
<input type="radio" name="q5" value="d" id="q5d"><label for="q5d">Answer 4</label><br/>        
</ul>        

<p class="question">6. What is the answer to this question?</p>        

<ul class="answers">            
<input type="radio" name="q6" value="a" id="q6a"><label for="q6a">Answer 1</label><br/>            
<input type="radio" name="q6" value="b" id="q6b"><label for="q6b">Answer 2</label><br/>            
<input type="radio" name="q6" value="c" id="q6c"><label for="q6c">Answer 3</label><br/>            
<input type="radio" name="q6" value="d" id="q6d"><label for="q6d">Answer 4</label><br/>        
</ul>       

<p class="question">7. What is the answer to this question?</p>        

<ul class="answers">            
<input type="radio" name="q7" value="a" id="q7a"><label for="q7a">Answer 1</label><br/>            
<input type="radio" name="q7" value="b" id="q7b"><label for="q7b">Answer 2</label><br/>            
<input type="radio" name="q7" value="c" id="q7c"><label for="q7c">Answer 3</label><br/>            
<input type="radio" name="q7" value="d" id="q7d"><label for="q7d">Answer 4</label><br/>        
</ul>        

<p class="question">8. What is the answer to this question?</p>        

<ul class="answers">            
<input type="radio" name="q8" value="a" id="q8a"><label for="q8a">Answer 1</label><br/>            
<input type="radio" name="q8" value="b" id="q8b"><label for="q8b">Answer 2</label><br/>            
<input type="radio" name="q8" value="c" id="q8c"><label for="q8c">Answer 3</label><br/>            
<input type="radio" name="q8" value="d" id="q8d"><label for="q8d">Answer 4</label><br/>       
</ul>        

<p class="question">9. What is the answer to this question?</p>        

<ul class="answers">            
<input type="radio" name="q9" value="a" id="q9a"><label for="q9a">Answer 1</label><br/>            
<input type="radio" name="q9" value="b" id="q9b"><label for="q9b">Answer 2</label><br/>            
<input type="radio" name="q9" value="c" id="q9c"><label for="q9c">Answer 3</label><br/>            
<input type="radio" name="q9" value="d" id="q9d"><label for="q9d">Answer 4</label><br/>        
</ul>        

<p class="question">10. What is the answer to this question?</p>        

<ul class="answers">           
<input type="radio" name="q10" value="a" id="q10a"><label for="q10a">Answer 1</label><br/>            
<input type="radio" name="q10" value="b" id="q10b"><label for="q10b">Answer 2</label><br/>            
<input type="radio" name="q10" value="c" id="q10c"><label for="q10c">Answer 3</label><br/>            
<input type="radio" name="q10" value="d" id="q10d"><label for="q10d">Answer 4</label><br/>        
</ul>        

<br/>
<div id="results">            
Show me the answers!       
</div>                

<div id="category1">            
<p>              
<strong>Question 1:</strong> The correct answer is the <strong>Answer 1</strong>.</p>        
</div>        

<div id="category2">            
<p>              
<strong>Question 2:</strong> The correct answer is <strong>Answer 2</strong>.</p>        
</div>        

<div id="category3">            
<p>                
<strong>Question 3:</strong> The correct answer is <strong>Answer 3</strong>.</p>        
</div>        

<div id="category4">            
<p>               
<strong>Question 4:</strong> The correct answer is <strong>Answer 4</strong>.</p>        
</div>        

<div id="category5">            
<p>                
<strong>Question 5:</strong> The correct answer is <strong>Answer 1</strong>.</p>        
</div>        

<div id="category6">            
<p>                
<strong>Question 6:</strong> The correct answer is <strong>Answer 2</strong>.</p>        
</div>        

<div id="category7">            
<p>                
<strong>Question 7:</strong> The correct answer is <strong>Answer 3</strong>.</p>        
</div>        

<div id="category8">            
<p>               
<strong>Question 8:</strong> The correct answer is <strong>Answer 4</strong>.</p>        
</div>        

<div id="category9">           
<p>               
<strong>Question 9:</strong> The correct answer is <strong>Answer 1</strong>.</p>        
</div>        

<div id="category10">            
<p>                
<strong>Question 10:</strong> The correct answer is <strong>Answer 2</strong>.</p>        
</div>        

<div id="category11">            
<p>                
You answered them all right!</p>        
</div>
</body>
</html>

I faced a big problem on my iOS Coding. My requirement is I have a HTML file. That file contain some multiple choice Q&A. I Load that html file in a UIWebView. And when I click that answer button I have to retrieve which button is clicked on webView.

I have to retrieve that method from html file.

How is it possible?

Its not a duplicate Q, I already googled on this and whatever i got, its not satisfying my requirement.

My code is like below : 

- (void)viewDidLoad {
    [super viewDidLoad];

    NSString *path;
    NSBundle *thisBundle = [NSBundle mainBundle];
    path = [thisBundle pathForResource:@"Untitled" ofType:@"html"];
    NSURL *instructionsURL = [NSURL fileURLWithPath:path];
   [_webview loadRequest:[NSURLRequest requestWithURL:instructionsURL]];
  }
  - (void)webViewDidFinishLoad:(UIWebView*)theWebView
  {
    NSString* returnValue =[theWebView stringByEvaluatingJavaScriptFromString:@"myFunction()"];
    NSLog(@"returnValue = %@ ",returnValue);
  }
  - (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error
  {
     NSLog(@" didFailLoadWithError");
  }

enter image description here

But my output is : Sample_JS[2218:44719] returnValue =

Please help me out ....

Upvotes: 5

Views: 1871

Answers (4)

Leo
Leo

Reputation: 24714

In your code,this is the order that things happen:

  1. You load the request in viewDidload
  2. Your webview finished load.So you get the value selected.But at this time.You have not select anything.
  3. When you select a item, you did not do anything to tell iOS that you select one

So,what I suggest is using WKWebview,it is good to work withs JS Code.

  1. In your js code,add a button to submit. Then in the button action function

    function submit () {
    var message = //here get all your selected items
    window.webkit.messageHandlers.observe.postMessage(message);
 }

  2. In ViewController,create WKUserContentController to handle notification

    WKWebViewConfiguration *configuration = [[WKWebViewConfiguration alloc]init];
WKUserContentController *controller = [[WKUserContentController alloc]
                                   init];
[controller addScriptMessageHandler:self name:@"observe"];
 configuration.userContentController = controller;
_webView = [[WKWebView alloc] initWithFrame:self.view.frame
                          configuration:configuration];

  3. In delegate method,handle js event

    -(void)userContentController:(WKUserContentController *)userContentController
  didReceiveScriptMessage:(WKScriptMessage *)message {
//message.body
}

Update whole project

#import <WebKit/WebKit.h>
@interface ViewController ()<WKScriptMessageHandler>

@property (strong, nonatomic) WKWebView  * webview;

@end

@implementation ViewController

- (void)viewDidLoad {
    NSString *path;
    NSBundle *thisBundle = [NSBundle mainBundle];
    path = [thisBundle pathForResource:@"Untitled" ofType:@"html"];
    NSURL *instructionsURL = [NSURL fileURLWithPath:path];

    WKWebViewConfiguration *configuration = [[WKWebViewConfiguration alloc]init];
    WKUserContentController *controller = [[WKUserContentController alloc]
                                       init];
    [controller addScriptMessageHandler:self name:@"observe"];
    configuration.userContentController = controller;
    _webview = [[WKWebView alloc] initWithFrame:self.view.frame
                              configuration:configuration];
    [_webview loadRequest:[NSURLRequest requestWithURL:instructionsURL]];
    [self.view addSubview:self.webview];
}

-(void)userContentController:(WKUserContentController *)userContentController didReceiveScriptMessage:(WKScriptMessage *)message{
    NSLog(@"%@",message.body);
}

And htmlfile

<html>
<head>
<script type="text/javascript">
function getFirstSelect(){
    var rates = document.getElementsByName('q1');
    var rate_value;
    for(var i = 0; i < rates.length; i++){
        if(rates[i].checked){
            rate_value = rates[i].value;
            break;
        }
    }
    window.webkit.messageHandlers.observe.postMessage(rate_value);
}
</script>

<link rel="stylesheet" type="text/css" href="style.css" />
</head>
<body>
<p class="question">1. What is the answer to this question?</p>

<ul class="answers">
<input type="radio" name="q1" value="a" id="q1a"><label for="q1a">Answer 1</label><br/>
<input type="radio" name="q1" value="b" id="q1b"><label for="q1b">Answer 2</label><br/>
<input type="radio" name="q1" value="c" id="q1c"><label for="q1c">Answer 3</label><br/>
<input type="radio" name="q1" value="d" id="q1d"><label for="q1d">Answer 4</label><br/>
</ul>

<div id="Submit">
     <button onclick="getFirstSelect()">Submit</button>
</div>

</body>
</html>

When click submit enter image description here

This is test project,I believe you can figure out rest by yourself

Upvotes: 5

Soumya Ranjan
Soumya Ranjan

Reputation: 4843

Finally I am able to solve this Big Issue..

First Set the delegate method for your WebView.

 - (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType
{
 if ([[[request URL] absoluteString] hasPrefix:@"ios:"])
 {
    // Call the given selector
    [self performSelector:@selector(webToNativeCall)];
    return NO;
 }
 return YES;
}

- (void)webToNativeCall
{
 NSString *returnvalue =  [self.webview stringByEvaluatingJavaScriptFromString:@"returnVal()"];
 NSLog(@"returnvalue == %@",returnvalue);
}

In javascript file :

function getData ()
{
   window.location  = 'ios:webToNativeCall';
}
function returnVal(){
  return values;
}

Upvotes: 1

Santu C
Santu C

Reputation: 2654

Please check below code , I have tested in my system . 

- (void)viewDidLoad
{
    [super viewDidLoad];

    NSString *htmlFile = [[NSBundle mainBundle] pathForResource:@"File" ofType:@"html"];
    NSString* htmlString = [NSString stringWithContentsOfFile:htmlFile encoding:NSUTF8StringEncoding error:nil];
    [self.webView loadHTMLString:htmlString baseURL:nil];

}

Button action method to check html results after click on radio button - 

- (IBAction)action:(id)sender {

    NSString* javaScriptString = @"document.querySelector('input[name=\"sex\"]:checked').value;";
    NSLog(@"%@",  [self.webView stringByEvaluatingJavaScriptFromString: javaScriptString]);
}

Html Files - 

<!DOCTYPE html>
<html>
    <body>

        <form action="">
            <input type="radio" name="sex" value="male">Male<br>
            <input type="radio" name="sex" value="female">Female
        </form>

    </body>
</html>

Upvotes: 0

Mahesh
Mahesh

Reputation: 996

You have to make a global variable in JavaScript which store the value of answer. your function myFunction() was called after the webview load and when user was selected at that time there are no function called. so you have to call the function rapidly in some time and check it what is the value

Upvotes: 0

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