I am writing a function that collaborates with a JS web page. I use UIWebView to contain the webpage and then situation has become complicated when I want the web page to communicate with my app.
Calling a javascript function in UIWebView is easy by using the – stringByEvaluatingJavaScriptFromString: method
But is there any easier way to call an obj-c function in the web page, using javascript? I tried using the UIWebView delegate method, but I think it's too hacky.
Any advice?
I guess using delegate is the only (one or two) methodology you can use in iOS WebView. But there are several wrappers that may help you easy out.
EasyJSWebView - This replicates the development experience as in Android. In Android, you can simply use the addJavascriptInterface() method in WebView to bridge the Javascript to Java. EasyJSWebView provides both sync-style and async-style for getting the return value from Objective-C methods.
WebViewJavascriptBridge - The code may look a little bit like socket programming. You can pass data to and fro between the "server" in Objective-C and the "client" in Javascript.
GAJavaScript - This may provide a better DOM manipulation experience.
Take a look at all of them and choose one that fits your need.
Yes it does feel hacky and is a little laggy but you need to do it with the UIWebViewDelegate
function init()
{
$('input').on('click', function(e) { answerBoxShouldBeginEditing(e); });
}
function answerBoxShouldBeginEditing(e)
{
var object = e.toElement;
var answer = $(object).attr('name');
var request = 'engine:' + answer;
var iframe = document.createElement('IFRAME');
iframe.setAttribute('src', request);
document.documentElement.appendChild(iframe);
iframe.parentNode.removeChild(iframe);
iframe = null;
}
- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType
{
NSString *requestString = [[request URL] absoluteString];
if ([requestString hasPrefix:#"engine:"]) {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Hello" message:nil delegate:self cancelButtonTitle:#"OK" otherButtonTitles:nil];
[alert show];
return NO;
}
return YES;
}
If you are considering to upgrade to WKWebView, XWebView may be the best solution.
I am writing a Javascript application and am going to wrap it in a native iOS application. I would like to block user interaction on the UIWebView containing the JS app for a second or two following an event.
Normally I would use the self.webView.userinteractionenabled = NO but the event is triggered in Javascript. How can I block the user from interacting with the web view?
Guessing return false on a touch event of some sort? It's scrolling that I want to block.
Thanks!
When the event occurs in your Javascript code you can send a message to the native wrapper by using the following method:
Set up the following UIWebViewDelegate method (don't forget to set the delegate for the UIWebView):
- (BOOL)webView:(UIWebView*)webView shouldStartLoadWithRequest:(NSURLRequest*)request navigationType:(UIWebViewNavigationType)navigationType {
NSURL *url = [request URL];
if ([[url scheme] isEqualToString:#"block"]) {
// do the your blocking code here
return NO;
}
return YES;
}
Now when your event happens, call the delegate method from your javascript code:
window.location.href = "block://";
Is it possible to detect if the user is accessing through the browser or application using JavaScript?
I'm developing a hybrid application to several mobile OS through a web page and a PhoneGap application and the goal would be to:
Use the same code independently of the deployment target
Add PhoneGap.js file only when the user agent is an application
You could check if the current URL contains http protocol.
var app = document.URL.indexOf( 'http://' ) === -1 && document.URL.indexOf( 'https://' ) === -1;
if ( app ) {
// PhoneGap application
} else {
// Web page
}
Quick solution comes to mind is,
onDeviceReady
shall help you. As this JS call is invoked only by the Native bridge (objC or Java), the safari mobile browser will fail to detect this. So your on device app(phone gap) source base will initiate from onDeviceReady.
And if any of the Phonegap's JS calls like Device.platform or Device.name is NaN or null then its obviously a mobile web call.
Please check and let me know the results.
I figured out a way to do this and not rely on deviceready events thus, keeping the web codebase intact...
The current problem with using the built in deviceready event, is that when the page is loaded, you have no way of telling the app: "Hey this is NOT running on an mobile device, there's no need to wait for the device to be ready to start".
1.- In the native portion of the code, for example for iOS, in MainViewController.m there's a method viewDidLoad, I am sending a javascript variable that I later check for in the web code, if that variable is around, I will wait to start the code for my page until everything is ready (for example, navigator geolocation)
Under MainViewController.m:
- (void) viewDidLoad
{
[super viewDidLoad];
NSString* jsString = [NSString stringWithFormat:#"isAppNative = true;"];
[self.webView stringByEvaluatingJavaScriptFromString:jsString];
}
2.- index.html the code goes like this:
function onBodyLoad()
{
document.addEventListener("deviceready", onDeviceReady, false);
}
function onDeviceReady(){;
myApp.run();
}
try{
if(isAppNative!=undefined);
}catch(err){
$(document).ready(function(){
myApp.run();
});
}
PhoneGap has window.PhoneGap (or in Cordova, it's window.cordova or window.Cordova) object set. Check whether that object exists and do the magic.
Inside the native call where the url for the phonegap app is loaded you add a parameter target with value phonegap. So the call for android becomes something like this.
super.loadUrl("file:///android_asset/www/index.html?target=phonegap");
Your website using this code won't be called with the extra parameter, so we now have something different between the two deploying platforms.
Inside the javascript we check if the parameter exists and if so we add the script tag for phonegap/cordova.
var urlVars = window.location.href.split('?');
if(urlVars.length > 1 && urlVars[1].search('target=phonegap') != -1){
//phonegap was used for the call
$('head').append('<script src="cordova.js"></script>');
}
A small caveat: this method requires to change the call to index.html in phonegap for each different targeted mobile platform. I am unfamiliar where to do this for most platforms.
what if you try following :
if(window._cordovaNative) {
alert("loading cordova");
requirejs(["...path/to/cordova.js"], function () {
alert("Finished loading cordova");
});
}
I am using the same code for both phonegap app and our web client. Here is the code that I use to detect if phonegap is available:
window.phonegap = false;
$.getScript("cordova-1.7.0.js", function(){
window.phonegap = true;
});
Keep in mind that phonegap js file is loaded asynchronously. You can load it synchronously by setting the correct option of a nifty jquery $.getScript function.
Note that approach does make an extra GET request to grab phonegap js file even in your webclient. In my case, it did not affect the performance of my webclient; so it ended up being a nice/clean way to do this.Well at least until someone else finds a quick one-line solution :)
It sounds like you are loading another webpage once the webview starts in the Phonegap app, is that correct? If that's true then you could add a param to the request url based on configuration.
For example, assuming PHP,
App.Config = {
target: "phonegap"
};
<body onload="onbodyload()">
var onbodyload = function () {
var target = App.Config.target;
document.location = "/home?target=" + target;
};
Then on the server side, include the phonegap js if the target is phonegap.
There is no way to detect the difference using the user agent.
The way I'm doing it with is using a global variable that is overwritten by a browser-only version of cordova.js. In your main html file (usually index.html) I have the following scripts that are order-dependent:
<script>
var __cordovaRunningOnBrowser__ = false
</script>
<script src="cordova.js"></script> <!-- must be included after __cordovaRunningOnBrowser__ is initialized -->
<script src="index.js"></script> <!-- must be included after cordova.js so that __cordovaRunningOnBrowser__ is set correctly -->
And inside cordova.js I have simply:
__cordovaRunningOnBrowser__ = true
When building for a mobile device, the cordova.js will not be used (and instead the platform-specific cordova.js file will be used), so this method has the benefit of being 100% correct regardless of protocols, userAgents, or library variables (which may change). There may be other things I should include in cordova.js, but I don't know what they are yet.
Ive ben struggling with this aswell, and i know this is an old thread, but i havent seen my approach anywhere, so thought id share incase itll help someone.
i set a custom useragent after the actual useragent :
String useragent = settings.getUserAgentString();
settings.setUserAgentString(useragent + ";phonegap");
that just adds the phonegap string so other sites relying on detecting your mobile useragent still works.
Then you can load phonegap like this:
if( /phonegap/i.test(navigator.userAgent) )
{
//you are on a phonegap app, $getScript etc
} else {
alert("not phonegap");
}
To my mind you try to make issue for self. You didn't mentioned your development platform but most of them have different deployment configuration. You can define two configurations. And set variable that indicates in which way code was deployed.
In this case you don't need to care about devices where you deployed your app.
Short and effective:
if (document.location.protocol == 'file:') { //Phonegap is present }
Similar to B T's solution, but simpler:
I have an empty cordova.js in my www folder, which gets overwritten by Cordova when building. Don't forget to include cordova.js before your app script file (it took my one hour to find out that I had them in wrong order...).
You can then check for the Cordova object:
document.addEventListener('DOMContentLoaded', function(){
if (window.Cordova) {
document.addEventListener('DeviceReady', bootstrap);
} else {
bootstrap();
}
});
function bootstrap() {
do_something()
}
New solution:
var isPhoneGapWebView = location.href.match(/^file:/); // returns true for PhoneGap app
Old solution:
Use jQuery, run like this
$(document).ready(function(){
alert(window.innerHeight);
});
Take iPhone as example for your mobile application,
When using PhoneGap or Cordova, you'll get 460px of WebView, but in safari, you'll lose some height because of browser's default header and footer.
If window.innerHeight is equal to 460, you can load phonegap.js, and call onDeviceReady function
Nobody mentioned this yet, but it seems Cordova now supports adding the browser as a platform:
cordova platforms add browser
This will automatically add cordova.js during run-time, which features the onDeviceReady event, so that you do not need to fake it. Also, many plugins have browser support, so no more browser hacks in your code.
To use your app in the browser, you should use cordova run browser. If you want to deploy it, you can do so using the same commands as the other platforms.
EDIT: forgot to mention my source.
Solution: Patch index.html in Cordova and add cordova-platform="android" to <html> tag, so that cordova-platform attribute will be only present in Cordova build and missing from original index.html used for web outside of Cordova.
Pros: Not rely on user agent, url schema or cordova API. Does not need to wait for deviceready event. Can be extended in various ways, for example cordova-platform="browser" may be included or not, in order to distinguish between web app outside of Cordova with Cordova's browser platform build.
Merge with config.xml
<platform name="android">
<hook src="scripts/patch-android-index.js" type="after_prepare" />
</platform>
Add file scripts/patch-android-index.js
module.exports = function(ctx) {
var fs = ctx.requireCordovaModule('fs');
var path = ctx.requireCordovaModule('path');
var platformRoot = path.join(ctx.opts.projectRoot, 'platforms/android');
var indexPath = platformRoot + '/app/src/main/assets/www/index.html';
var indexSource = fs.readFileSync(indexPath, 'utf-8');
indexSource = indexSource.replace('<html', '<html cordova-platform="android"');
fs.writeFileSync(indexPath, indexSource, 'utf-8');
}
Notes: For other than android, the paths platforms/android and /app/src/main/assets/www/index.html should be adjusted.
App can check for cordova-platform with
if (! document.documentElement.getAttribute('cordova-platform')) {
// Not in Cordova
}
or
if (document.documentElement.getAttribute('cordova-platform') === 'android') {
// Cordova, Android
}
I'm developing an iOS app with a UIWebView instance.
If the user touches an object in a webpage shown by the web view, how can I extract metadata regarding the object touched (such as an "id" for an HTML element) over in Objective C land?
[I'm not interested in whether the web view was touched or not, I'm only interested in what part of the page was touched and being able to act on this.]
You probably need to do this in JavaScript land. In your webview set up some javascript to monitor the click (e.g. element.onclick = function() { ... }, or use jQuery if that's easier).
Now you can call out to the native code in your app by using a made up url and then intercepting it using the webview delegate, e.g.
//in your web page, in javascript
myDiv.onclick = function() { document.location.href = 'http://madeupdomain/' + this.id};
//webview delegate in cocoa
- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType
{
NSURL *URL = [request URL];
NSString *host = URL.host;
if ([host isEqualToString:#"madeupdomain"])
{
NSString *theDivID = URL.path;
//now do something based on the div id value
return NO;
}
return YES;
}
This is essentially how frameworks like PhoneGap communicate between the webview and the native code.
I have a webpage loaded in a UIWebView, and a javascript function of the page needs to data from native iOs app, a NSString. How can a Js function access the data in native app?
Thanks,
lvreiny
You can execute JavaScript in your UIWebView from Obj-C. Simply call [webView stringByEvaluatingJavaScriptFromString:#"myJavaScript"];.
I could imagine a setup like this:
Webpage
<html>
<head>
<script type="text/javascript">
function callmeFromObjC(para1) {
// do something
alert(para1);
}
</script>
</head>
<body>
</body>
</html>
Objective-C
NSString *myParameter = #"myParameter";
[webView stringByEvaluatingJavaScriptFromString:[NSString stringWithFormat:#"callmeFromObjC('%#')", myParameter]];
With WebViewJavaScriptBridge you can achieve two way communication between javaScript and iOS.
Check this link below for WebViewJavaScriptBridge .
I used this bridge for one of my application for communication between iOS and JS and also vice versa.
https://github.com/marcuswestin/WebViewJavascriptBridge.
I created an iOS/JS library to help make this easier -- that is, communication in both directions using similar methods. You can check it out here: https://github.com/tcoulter/jockeyjs
Let the javascript load a custom URL, which your app intercepts. It than can parse it, prepare the data and pass it on to your webpage via stringByEvaluatingJavaScriptFromString:.
[webView loadHTMLString:#"<script src=\"filename.js\"></script>"
baseURL:[NSURL fileURLWithPath:[[NSBundle mainBundle] resourcePath]]];
NSString *result = [webView stringByEvaluatingJavaScriptFromString:#"function(parameter)"];
Give feedback to iOS
window.location = customprefix://function/parameter=value
- (BOOL)webView:(UIWebView*)webView shouldStartLoadWithRequest:(NSURLRequest*)request navigationType:(UIWebViewNavigationType)navigationType {
if ([[URL scheme] isEqualToString:#"customprefix"]) {
// handle function name and paramters
}
}
I also wrote a guide on how to call and handle different javascript functions from within iOS.
http://www.dplusmpage.com/2012/07/20/execute-javascript-on-ios/
Sample code for this is available here,you can check it....very usefull
http://ramkulkarni.com/blog/framework-for-interacting-with-embedded-webview-in-ios-application/