Is there any way to use flutter in Windows in order to call javascript methods that would require a browser? For example if I use a js method that does a simple task as return a + b it works, but if i try to use browser methods like window.open() it does not
Things I tried:
InAppWebView, but does not support Windows
flutter_html, i could make a page according to a given html code, but the javascripts functions would not run
Related
I am hoping to confer on a strategy for a flutter web app (as can ignore mobile cases here) to get chrome extension info for a Polkadot.js wallet from the Polkadot browser extension.
My first thought is to use dart's JS library and use the Polkadot extension JS package and then try and pull the info from there. However, I'm not sure how to properly use this in flutter as it is a whole package full of dependencies, not just a single JS file. Also it is in TS not JS. Any thoughts here?
Eg., I need a JS file to be able to call this; and for flutter to in turn call the JS file:
import {
web3Enable,
} from '#polkadot/extension-dapp';
By writing out a "bridging" layer, you can do it easily.
Firstly, create a normal javascript (or typescript) application (nothing related to Flutter). You should be able to happily use the polkadot lib in your js/ts code without any problem. You may need to learn a bit about how to develop js code normally (e.g. you can depend on polkadot using npm, etc).
One small thing is that, you should "expose" some object publicly in your js/ts code. For example, your code may look like window.myFancyFunction = function() { call_some_polkadot_function(); }. Of course you can do more things like exposing other functions/objects/...
Then, you can bundle this normal js/ts application into a .js file. This is still very normal for js/ts developers and should have nothing special to deal with here, and you still do not need to touch Flutter at this stage.
Next, load this single-filed .js file when you are loading your Flutter Web application. You may simply do this by editing your Flutter Web's html file and add <script src="my_single_filed_js_mentioned_above.js" />. Notice that, when loading this script, it simply sets window.myFancyFunction and does not do anything more. Still very trivial here, should have no problem.
Lastly, in your Flutter Web code, i.e. Dart code, call that window.myFancyFunction function. For example, Flutter Web : How to run javascript using dart js says you can do import 'dart:js' as js; js.context.callMethod('myFancyFunction', ['some arguments']);
l split my GWT code in different different modules like
PrintPermit.gwt.xml
EmployeeResponse.gwt.xml
Rejected.gwt.xml
and every module has its own entry point class
in my HTML host page I am calling script like
ae.init.EmployeeResponse.nocache.js
I have a menu like
Print Application
Reject Application
New application
whenever user will click on new application default new application will open
as I declare EmployeeResponse.nocache.js statically in my HTML host page.
now I want to call other modules on click button print and reject button
how can i call nocache js for print and reject modules. is there any way to dynamic call.
please help me guys.
Here's how I've done it in the past:
First of all, in the module you want to export, you need to make sure that the code you're going to export doesn't end up obfuscated. This can be accomplished with the liberal use of #JsType; this is the new way of exporting JS, available in GWT 2.8 (as opposed to JSNI).
Your module's entry point onModuleLoad can be empty; it doesn't need to do anything.
Include your JS in the HTML you want to use (maybe the same page as your "main" module)
Check JSInterop documentation (perhaps the one available here) on how you can use native JS in your GWT app (because now, your GWT module became native JS). Import the classes via JSInterop from your library, and use them.
Please be aware of the async nature of the GWT JS loading; your library will be loading in an async manner, just like any JS application (and therefore, it won't be available immediately when your page loads). To overcome this, I've placed a call to a native JS function in my library's onModuleLoad function (i.e. to make sure you notify any potential listeners that the code has loaded; because when onModuleLoad runs, the code surely loaded).
There is a example of an InterAppEventBus:
https://github.com/sambathl/interapp-eventbus
which shows the communication between two GWT applications.
I have adopted it and replaced JSNI with Elemental2 and WebStorage:
https://github.com/FrankHossfeld/InterAppEventBus
Hope that helps.
You can achieve this through separate Html file for each module.
So first of all create separate html for each application e.g. PrintPermit.html and specify corresponding nocache.js in each html.
then on your buttons in menu, add click handlers and in each on click load a corresponding html through Window.open()
e.g. for PrintPermit,
printPermitButton.addClickHandler(new ClickHandler{
#Override
public void onClick(ClickEvent arg0) {
String s = GWT.getHostPageBaseURL() + "PrintPermit.html";
Window.open(s, "PrintPermit", "");
}
});
Please note the window.open will open in new tab in browser, you can also use gwt iframe to open html in same browser page.
Each module will have corresponding nocache.js and will be loaded through html using Window.open()
I want to implement XMPP chat functionality in my system using converse.js for client side chat interface. but when i use converse.js in my layout page, browser showing me error like
$(...).datetimepicker is not a function
$(...).dataTable is not a function.
I have used bootstrap datetimepicker and datatables. It seems like jquery conflictions.
I have tried to resolve conflictions by changing place of some jquery files. but i didn't get success. So how can i remove conflictions?
EDIT: As of version 3.0.1 this shouldn't be an issue anymore. In previous builds the $.noConflict call wasn't being made. This is now fixed in 3.0.1. If you're using an older version, then the text below is still relevant.
Converse.js comes bundled with jQuery. It uses jQuery's noConflict method to relinquish control of the $ variable and therefore to avoid conflicts with other versions of jQuery, but apparently this doesn't always work reliably.
There are a few things you can try:
Load converse.js before all your other JS libraries.
Alternatively, drop your own jQuery and instead use the one included in converse.js. You can access it via converse.env.jQuery.
Or alternatively use the converse.js bundle that doesn't include jQuery: https://cdn.conversejs.org/dist/converse-no-jquery.min.js
In GWT web/production mode, Java code is complied into Javascript code that is rendered in the browser.
Also,I have always thought that in GWT development mode, GWT developer plugin compiles my Java code into JavaScript to render it in the browser. But after reading on some site, I came to know that there's no compiling of code to JavaScript to view it in the browser in development mode.
So, I wonder: What are all these widgets I see in the browser during this mode if they aren't JavaScript code?. I don't understand it.
Please help understanding this.
The crux of the Dev Mode is that your code runs in Java. This is a prerequisite if you can use a standard Java debugger. You'll find a high-level overview in the GWT documentation.
The magic happens with JSNI methods and overlay types: when a class is loaded, all its JSNI methods are extracted and their JS body is sent to the browser, ready to be executed (as JavaScript then), and the class is rewritten on the fly to reimplement the JSNI method to make a call to the browser (via the Dev Plugin you installed there and is triggered by ?gwt.codesvr= in the URL) to execute the corresponding JS function. This is the reason why Java objects are seen as opaque handles in JSNI methods; they're assigned a numeric ID to pair the Java object with a dummy JS object on the server-side. A similar though more complex rewriting is done for overlay types, and the same ID mapping is used when JS objects are passed to Java code (as overlay types).
BTW, Super Dev Mode compiles to JavaScript (almost) on the fly.
I have a Qt application containing a Webkit module and using Dart (compiled to JS). It's like a bare-bones browser written in Qt. The application basically replaces certain text on the webpage with different text. I want users to be able to make their own Dart files to replace their own text with their own different text.
Any recommendations for approaches to creating a plugin system?
I think that this question needs a little clarification: are you asking about using Dart for scripting Qt applications (where Dart plays the role of a scripting language), or are you asking about a plugin system for Dart application that is compiled to JS and used in a Qt application, probably via QtScript (in which case, the role of a scripting language is played by JavaScript)?
I presume that it is the latter variant (and I don't know enough about Qt to be able to answer about the former variant anyway).
Let's assume that all plugins for the Dart application are available at the build time of that Qt application, so that you don't need to compile Dart to JS dynamically. Then, if you compile a Dart script, resulting JS will include all necessary code from its #imports. All you need is to create a proper script that imports all plugins and calls them (importing isn't enough, as dead code will be eliminated).
Maybe an example will be more instructive. Let's say that you want to allow plugins to do some work on a web page. One way you might structure it is that every plugin will be a separate #library with a top-level function of a well known name (say doWork). Example of a plugin:
// my_awesome_plugin.dart
#library('My Awesome Plugin')
doWork(page) {
page.replaceAll('JavaScript is great', 'Dart is great');
}
You can have as many plugins of this nature as you wish. Then, you would (at the build time) generate a following simple main script in Dart:
// main.dart
// these lines are automatically generated -- for each plugin file,
// one #import with unique prefix
#import('my_awesome_plugin.dart', prefix: 'plugin1');
#import('another_plugin.dart', prefix: 'plugin2');
main() {
var page = ...; // provided externally, from your Qt app
// and these lines are automatically generated too -- for each plugin,
// call the doWork function (via the prefix)
plugin1.doWork(page);
plugin2.doWork(page);
}
Then, if you compile main.dart to JavaScript, it will include all those plugins.
There are other possibilities to structure the plugin system: each plugin could be a class implementing a specific interface (or inheriting from a specific base class), but the general approach would be the same. At least the approach that I would recommend -- making each plugin a separate library.
You probably don't like the step with generating the main script automatically, and I don't like it either. But currently, Dart only allows one way to dynamically load new code: spawning new isolates. I'm not sure how (or even if) that would work in QtScript, because isolates are implemented as web workers when compiled to JavaScript, so I won't discuss this here.
Things will get more complicated if you want to support compiling Dart scripts at the runtime of your Qt application, but I think that I'm already guessing too much about your project and I might be writing about something you don't really need. So I'll finish it like this for now.