can i design my web pages in html and css instead of java methods and use gwt only in parts of page that i need ajax? and which one is better gwt, extgwt, vaadin(it run apps in server-side.can i also use it in client-side?), etc...? do i also need to know javascript for using gwt?
thanks
can i design my web pages in html and
css instead of java methods and use
gwt only in parts of page that i need
ajax?
Yes, you can. You can create a div on your HTML page and insert your GWT widget there.
which one is better gwt, extgwt,
vaadin(it run apps in server-side.can
i also use it in client-side?)
I don't know about vaadin but Ext-GWT is a set of ready made components to use with GWT which make your life easier especially if you want to build an web app that looks and feels like a desktop application.
do i also need to know javascript for
using gwt?
No, it can be useful sometimes but is not necessary.
Related
I want to use History.js from Google Web Toolkit.
I know GWT has History functionality of it's own, but I don't like it because it uses the hashes in the URI, I want to use the new HTML5 History API as much as possible.
The only current way that I can think of to run History.js and GWT together is to write the History.js part in plain Javascript (or jQuery) and then manually call a GWT method.
It would be nice if it was possible to use the whole History.js functionality from within GWT's Java files.
No pain at all with that .
You just simple add your History js file on your document and you can use it .
Here i answered how you can use an external js in GWT .
Using externel js in GWT
After you call the native method you can continue with gwt method
So far what I have used with my gwt application is a simple FI, like #login, #welcome etc.
However I want to "refactor" my application in a more descriptive way, I need make it this way:
http://localhost:8080/main#login
http://localhost:8080/main#search
http://localhost:8080/profile#<username>
http://localhost:8080/api
etc.
Can I do this with GWT?
If you want to stay on the same GWT application, you'll have to use the HTML5 History API (pushState and onpopstate) instead of GWT's default History (or DefaultHistorian) implementation; which means your app would only work with browser supporting the HTML5 History API (or you'd have to provide a fallback).
This is possible with GWT, but if you don't know how to do it and/or how the HTML5 History API works, it'll cost you a lot (of time).
BTW, if you ever switch to the HTML5 History API, why keep some fragment identifiers?
The alternative is, as milan says, to split your app into smaller parts (/main, /profile, /api, etc.)
Yes, but /main and /profile are going to be separate (html) pages, so you'll have EntryPoint for each then (loading/unloading GWT modules). Is that want you want? Google's AdWords is an example (written in GWT), each tab is a separate HTML page (/dashboard/, /cm/CampaignMgmt, ...).
I really like the approach in GWT where you can define "divs", "spans" etc in a regular html page, then in the GWT entry point simply push a button or some other component inside the div.
So small example, here is a snippet of a gwt html page:
<body class='page'>
<iframe src="javascript:''" id="__gwt_historyFrame" tabIndex='-1' style="position: absolute; width: 0; height: 0; border: 0"></iframe>
<div>
Query Terms: <span id="txtQuery"></span>
<span id="btnQuery"></span><br>
...
</div>
</body>
And here is a small java snippet contained in the gwt entry point:
ClickHandler clickHandler = ...
TextBox txtQuery = new TextBox();
Button btnQuery = new Button("Query", clickHandler);
RootPanel.get("txtQuery").add(txtQuery);
RootPanel.get("btnQuery").add(btnQuery);
One of the reasons I like this approach is that it allows non java coders to design / write the html stuff, and I also like the separation between GWT / java code and the html code.
However... this may work well for a simple web page, but how do you scale this approach up into many webpages? From what I understand, the "GWT way" of doing things is to have one webpage and use history to hide and show various GWT components. I have built 2 projects in GWT using this standard technique, but recently discovered that you can do the sort of thing I showed above.
Is there any way of scaling the above 2 snippets into multiple html pages, where GWT injects its components into standard html pages?
here is no GWT way. At least not in GWT mission statement. If you want to pursue your aproach there are multiple ways how you can do it.
GWT app per page. (e.g. on each page a gwt app specific for this page is included). You simply compile a new GWT module for each page where you need some GWT functionality. You can use few of them together on one page, or none. This approach is good if you GWT apps are going to be really simple, and you don't need to use stuff like GXT Grid on every single page with different settings, otherwise you will waste user browser will have to download large chunks of JS code over and over, and this will be a big problem if you have a lot of pages.
One big GWT app for all pages. Just put everything into single GWT app, create some kind of switch (some js variable) so the app knows what it has to create. Some code splitting might be used, so on each page only things which are really required will be downloaded. Since the same JS will be used on each page, caching should solve the problem with downloading application code over and over (but you still have the problem with actually parsing/running the code very time user changes the page)
There is also a third approach, the most effective of all, but the hardest as well. As soon as the user loads one of the pages, there is no more navigation, gwt module simply takes template for page to which user wants to navigate, and replaces current html code with newly generated template. This is quite easy to achieve, if you will use TextResource from ClientBundle and HTMLPanel. The problem is with navigation in address field (GWT app will have to be responsible for changing the address, so the users can create bookmarks or send the link to their friends). You will use one single GWT script for this and some code splitting is recommended.
All three approaches are totally valid, depending on your requirements you can pick any of them. Also if all you want is to provide people ability to use HTML to layout GWT screens, you might want consider using combination of HtmlPanel and ClientBundle's TextResource.
If the goal is to have designers work on HTML rather than Java, then how about UiBinder? It'd give you what you want (separate HTML –or rather, XHTML-like– code from Java code) inside a GWT project.
I am making an app in GWT. It is like a dashboard and will have out of the widgets.
Now when we ship this out, there is a use case that the customer might want to create their own GWT widget and use this in the dashboard app.
As I understand it, they will not be able to do this since we cannot ship our source code which is needed to compile the whole app again once tag of their widget/module gets into the gwt.xml file of my app.
I cannot use anything other that GWT to make this dashboard. And their widget could be say a flash heapmap, a jquery widget/plugin, another GWT module, a jsp page that renders a visualization from back end.
So far my thoughts have been to provide a widget in my app which is a wrapper in the form of an Iframe and call their main page (they will provide url), and have an api to let my app and their widget talk.
But I would like to know if there are other / better approaches?
This is exactly the problem solved by google's OpenSocial widgets. There are a few opensource implementations: http://shindig.apache.org/ is one. You can look into integrating that in to your app. An added bonus is that you can then display widgets from other applications (such as atlassian jira) that also serve opensocial widgets.
Depending on how closed source your application is (can custom JS/HTML be added to pages?), you could always provide a native Javascript (JSNI) API for some custom dashboard widgets. The simplest solution I'm thinking of would be a JSNI method which your customers could call to set the HTML content of said widget. This method would allow them to use a variety of options such as JQuery widgets, their own GWT widget generated HTML or even an IFrame pointing to their JSP pages etc... You could then provide additional JSNI API methods which would allow them to interact with your app/widget in other ways as well. This would be better than the IFrame method because you wouldn't have to deal with cross domain scripting security issues.
I want to design a website using GWT. This is my understanding of how GWT pages will be delivered to the client browser - When the user puts in the URL into her browser she receives all the static HTML + GWT javascript, and then the javascript queries the server for the dynamic page content and adds it to the DOM. eg - For a blog page the content of the blog is queried by the javascript. is my understanding correct?
If I know that the content will surely be a part of the page(add does not depend on user clicking an expand button etc.), Will it be more efficient if the blog content was a part of the HTML initially served? Something that could be done by using a templating engine like django.
Is there a way to make a templating mechanism in GWT?
Yes, putting your content into the HTML will reduce the number of round trips the client makes to your server. It also means that the blog content won't have to wait for your GWT javascript to load before it can be displayed.
GWT itself isn't useful for a template system, but most servers that run GWT servlets will also support JSP pages. GWT works fine with these pages, you just need to put the GWT script tag in as usual. You will no doubt be able to find a ready-made templating solution but rolling your own is not too hard.