Evaluatejavascript ios example

evaluatejavascript ios example

In our first two projects we used Interface Builder for a lot of layout work, but here our layout will be so simple that we can do the entire thing in code. You see, before we were adding buttons and images to our view, but in this project the web view is going to take up all the space so it might as well be the view controller's main view.

So far, we've been using the viewDidLoad method to configure our view once its layout has loaded. This time we need to override the actual loading of the view because we don't want that empty thing on the storyboard, we want our own code.

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It will still be placed inside the navigation controller, but the rest is up to us. When we create the web view, we need to store it as a property so we can reference it later on. So, add this property to the class now:.

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However, I encourage you to structure your methods in an organized way, and because loadView gets called before viewDidLoad it makes sense to position the code above it too. Anyway, there are only three things we care about, because by now you should understand why we need to use the override keyword.

Hint: it's because there's a default implementation, which is to load the layout from the storyboard.

Flutter Webview - Part 2 (knocksbitlab.site)

Third, we make our view the root view of the view controller that web view. Yes, I missed out the second line, and that's because it introduces new concept: delegation.

Delegation is what's called a programming pattern — a way of writing code — and it's used extensively in iOS. And for good reason: it's easy to understand, easy to use, and extremely flexible. A delegate is one thing acting in place of another, effectively answering questions and responding to events on its behalf. But as smart as WKWebView is, it doesn't know or care how our application wants to behave, because that's our custom code. The delegation solution is brilliant: we can tell WKWebView that we want to be informed when something interesting happens.

In our code, we're setting the web view's navigationDelegate property to selfwhich means "when any web page navigation happens, please tell me — the current view controller. When you set any delegate, you need to conform to the protocol that matches the delegate.

Yes, all the navigationDelegate protocol methods are optional, but Swift doesn't know that yet.

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All it knows is that we're promising we're a suitable delegate for the web view, and yet haven't implemented the protocol. The fix for this is simple, but I'm going to hijack it to introduce something else at the same time, because this is an opportune moment.

First, the fix: find this line:. That's the fix. The order here really is important: the parent class superclass comes first, then all protocols implemented come next, all separated by commas.

We're saying that we conform to only one protocol here WKNavigationDelegate but you can specify as many as you need to.

This program is almost doing something useful, so before you run it let's add three more lines. Please place these in the viewDidLoad method, just after the super call:. I'm using hackingwithswift. Now, this probably seems like pointless obfuscation from Apple, but WKWebViews don't load websites from strings like www.

Fortunately it's not hard to do! Warning: Your URL must be complete, and valid, in order for this process to work. The third line enables a property on the web view that allows users to swipe from the left or right edge to move backward or forward in their web browsing.

This is a feature from the Safari browser that many users rely on, so it's nice to keep it around. Step one done!Join Stack Overflow to learn, share knowledge, and build your career. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. I need to return result of evaluating in this function. Can you suggest a solution? I just stumbled about the same problem and wrote a little Swift 3. I've found that the value of final statement in your injected javascript is the return value passed as the id argument to the completion function, if there are no exceptions.

So, for example:. Learn more. Asked 6 years, 3 months ago. Active 10 months ago. Viewed 67k times. Improve this question. I can solve it with some callback, but it is too complicated in my project.

Add a comment. Active Oldest Votes. I solved this problem by waiting for result until result value is returned. Improve this answer. UnknownStack UnknownStack 1, 16 16 silver badges 17 17 bronze badges. The issue with this code is that if a JS error is raised, your native function will run infinitely!

The solution would be to check a block safe boolean instead of resultString. The callback now called from the main Thread and if you lock the main thread in the while loop like in this solutionthe callback handler will be never called. Any ideas for iOS 12 or iOS 13? This solution doesn't work in iOS Does anyone has the working solution for iOS 13? Show 9 more comments. Slavcho 2, 3 3 gold badges 27 27 silver badges 43 43 bronze badges. Brams Brams 4 4 silver badges 9 9 bronze badges.

I can't use your code because of the RunLoop.Join Stack Overflow to learn, share knowledge, and build your career. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. I'm trying to use the new evaluateJavascript method in Android 4. Essentially if the javascript you execute in the WebView returns a value it'll be passed in the callback. Things to note about this is if you return a single value, you need to use setLenient true on a JSON reader for it to work.

The reason you may still want to use a parser for a string response is it is converted to a JSON value which means it will be wrapped in quotes. OK, so it turns out the result here is the result of the Javascript call - as if one were entering the command into a Javascript console. However, note that s might be a string "null" if JS returns proper nullso you obviously need to check that as the very first step.

Everyone's answer is great. I just add one more point. Don't put evaluateJavascript inside the method with JavascripInterface annotation like this way. Becasue it will block the JavaBridge Thread. Do it with this way. Otherwise you get no result.

Creating a simple browser with WKWebView

Learn more. How does evaluateJavascript work? Ask Question. Asked 7 years, 3 months ago. Active 5 months ago. Viewed 98k times. Improve this question.

evaluatejavascript ios example

CodingIntrigue CodingIntrigue You use WKWebView to display interactive web content in your app. Ideal for displaying HTML markup, styled text content, or complete web pages. Like this:. The most simple form of a web view is really bare-bones! You can, however, interact with the web view using a number of properties, objects and delegate protocols.

A WKWebView web view has two main delegate protocols and properties:. Of these two delegate protocols, the WKNavigationDelegate is probably used most frequently. Next, implement the five delegate functions described earlier. Set their function bodies to print functionso we can see the order in which the functions are called.

Finally, run the app! In the Console you see the order in which the delegate functions are called:. At this point the URL request has just been sent to the webserver and no response has come back yet. At this point it will attempt to load the web page HTML, as data is coming in.

evaluatejavascript ios example

A web page and an app are two distinct environments. And vice-versa, you can create full-fledged web apps that run inside Safari on iOS. How do you interact with a web page in a WKWebView? Simple navigation and interactions happen directly with functions on the webview instance, such as:.

JavaScript is used to code things in web browsers.

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Unfortunately, JavaScript-based interaction between the web view and your app is… interestingto say the least. When evaluation is done, its result is returned with the completionHandler closure.

An Extensive Guide to WKWebView

You can evaluate almost any kind of JavaScript code. That means you can inspect elements, check the values of properties, and assign event handlers.

And add the following function to your view controller:. The JavaScript code attaches an event listener to the web page.

evaluatejavascript ios example

This will post a message to the clickListener message handler any time a click event happens on the web page. The user script also attaches to that same clickListener handler.

The usefulness of WKWebView goes beyond displaying simple web pages in your app. After all, most of what you can do on a web page you can code natively in your iOS app — so why use web views at all?

One particularly useful scenario is when you want to create a layout or user interface with HTML. You could create the entire user interface natively, with views, buttons and labels. You could even store the recipe HTML pages on a webserver, and update them on-the-fly. With this function you can load HTML directly in the web view.WKWebView is a powerhouse on iOS, providing high-performance web rendering wherever and whenever you need.

So, if you want to solve a specific problem, or if you just want to see what WebKit is capable of, read on!

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All data is attached automatically. It only takes a line of code to setup. Start your free trial now and ship quality apps! Try it for free. Sponsor Hacking with Swift and reach the world's largest Swift community! This is inefficient, and also far harder than it needs to be. Having a dedicated webView property is helpful so that you can reference its properties and methods more easily later on.

If you intend to load URLs frequently, you might find it easier to wrap that behavior inside an extension:. For example, if you wanted to load a file called "help. That url. For example, this displays a heading message:. If you are referencing assets in your bundle such as images or CSS, you should specify Bundle. For example:. Second, make that object the navigation delegate of your web view. Finally, implement the decidePolicyFor method, adding any logic you want to decide whether the page should be loaded.

As an example, this implementation allows the user to visit the Apple homepage and nothing else:. If you were using your view controller you would write this:.

Finally, implement the decidePolicyFor method with whatever logic should decide whether the page is loaded internally or externally. For internal loads make sure you call the decisionHandler closure with. This can be done by observing the estimatedProgress property, like this:. You should now implement the observeValue forKeyPath: method, which will pass you a string saying what changed. You can use webView. Now implement the observeValue forKeyPath: method. This is all available inside the backForwardList property of web views, which itself contains the array backList and forwardList.

Inside each of those arrays you can read the URL for each page that was visited, along with the title that was used. For example, you can print out a list of all sites the user has already visited using this loop:. Once your web view has loaded some content, you can execute any JavaScript you like inside that rendered page by using the evaluateJavaScript method.

You can read through the complete list of cookies associated with a website by using the httpCookieStore property of your web view. This is buried under the configuration. User agents let your web servers identify the type of web browser that is accessing a page, and are commonly used to enable or limit which features are available. Note: There's nothing stopping you from changing the user agent when accessing other resources, but keep in mind that some sites might read the user agent string and get confused if it doesn't match what they expect.

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Fortunately, you can change that using the WKUIDelegate protocol: set an object to be the UI delegate of your web view and you can show custom alerts, manage your own tabs, and more. For example, you can make WKWebView show a custom alert controller when any web page uses the alert JavaScript function:. Although you can use the regular drawHierarchy method for converting a view to an image, WebKit comes with its own takeSnapshot method that lets you crop and size the image as needed.

Web views have built-in data detector support, which means they can make things like phone numbers, calendar events, and flight numbers into tappable links. Paul Hudson is the creator of Hacking with Swift, the most comprehensive series of Swift books in the world.

He's also the editor of Swift Developer Newsthe maintainer of the Swift Knowledge Baseand a speaker at Swift events around the world. If you're curious you can learn more here.Toggle navigation Hot Examples. EvaluateJavascript Examples. EvaluateJavascript - 10 examples found.

EvaluateJavascript extracted from open source projects. You can rate examples to help us improve the quality of examples. Programming Language: C CSharp. Frequently Used Methods. Show Hide. LoadHtmlString LoadRequest SizeToFit EvaluateJavascript AddSubview 4. GoBack 2.

GoForward 2. Reload 2. ValueForKeyPath 2. LoadHtmlString 1. Dispose 1. LoadData 1. RemoveFromSuperview 1. SetStyleId 1. StopLoading 1. Related in langs. Parse Go. Argmax Go. ActionManager Java. ServiceProxy Python. Example 1. Show file. File: WebViewController. The querystring has all of the parameters. Split '? Example 2.This is the date and time in which the logistic regression was created with microsecond precision.

True when the logistic regression has been built in development mode. The list of fields's ids that were excluded to build the logistic regression. The list of input fields' ids used to build the logistic regression. It includes a list of coefficients and the field's dictionary describing the fields and their summaries.

See here for more details. Specifies the list of ids of the field that the logistic regression predicts. In a future version, you will be able to share logistic regressions with other co-workers or, if desired, make them publicly available. The alternative key that gives read access to this logistic regression. This is the date and time in which the logistic regression was updated with microsecond precision.

Statistical tests to assess the quality of the model's fit to the data. This makes each field have roughly equivalent influence. Example: true category optional The category that best describes the cluster.

G-means iteratively takes existing clusters and tests whether the cluster's neighborhood appears Gaussian. If it doesn't the cluster is split into two. The default is to 5, which seems to work well in most cases.

A range of 1 - 10 is acceptable. Specifies the fields that won't be included in the cluster. Example: true name optional The name you want to give to the new cluster. Example: l1 replacement optional Whether sampling should be performed with or without replacement. A dictionary that maps cluster ids to dataset resources offering per field distribution summaries for each cluster.

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Each dataset resource can be serialized on-demand using the neighborhood of the cluster. With no seed, the cluster locations can vary from run to run. With a seed, the clusters are deterministic. All the information that you need to recreate or use the cluster on your own.

It includes: clusters: a list of centroids with a cluster object for each centroid. It also contains the distance distribution of the entire dataset to that center.

This will be 201 upon successful creation of the cluster and 200 afterwards. Make sure that you check the code that comes with the status attribute to make sure that the cluster creation has been completed without errors. This is the date and time in which the cluster was created with microsecond precision. In a future version, you will be able to share clusters with other co-workers or, if desired, make them publicly available.

This is the date and time in which the cluster was updated with microsecond precision. A dictionary that gives a numeric summary capturing the distribution of distances from the cluster's center to each of the points that fall into its neighborhood.

A status code that reflects the status of the cluster creation. Example: "My Seed" category optional The category that best describes the anomaly detector. Example: 1 constraints optional An experimental option which adds more predicates to each node in the tree.


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