The "problem" with the Vaadin RichTextArea component is not only in the fact that the editor field is inside an iframe
element, but as with all the other Vaadin components, you also have to keep in mind that your components will not be available when the DOM ready
callback (i.e. for example $(document).ready(function() {})
if using jQuery or the callback bound to a DOMContentLoaded
event) will execute.
This is because, as you know, when the Vaadin application starts, you actually don't have your components inside the DOM yet, but a vaadin bootstrap process will request and take care of the rendering of your UI for you. This is actually the principle with whom GWT works also (see How does GWT provide the correct Javascript code to every browser e.g. to carry out i18n and browser compatibility?) (after all Vaadin is based on GWT).
So e.g. if you use jQuery and you have a script like this loaded at the very beginning right after the vaadinBootstrap.js script loads and executes:
$(function() {
// this code will execute, but no components are available yet.
var rTa = $(".v-richtextarea"); // this won't select your Rich text area
var len = rTa.length // len will be 0 here, as no element matches the previous selector because as stated before, there is not an element with such a class in the DOM yet.
});
After this code executes, the very "heavy" process of creating the UI components and your layout begins, your widgetsets and/or the default one get loaded, and after that you have your beautiful UI set up and ready to interact with the user.
In order to customise an existent component such a RichTextArea and e.g. add a style element to the body of its iframe element, you can certainly venture into the depths of GWT and use JSNI as you did in your answer, but there's also another way to do it, in my opinion, more compact, simple, and does not require the usage of JSNI.
All you need to do is to implement a JavaScriptExtension
with a connector on the client side for your component (you can just extend Vaadin's RichTextArea), check out this simple code example:
#!java
package com.package.example;
@JavaScript({"vaadin://js/src/rich_text_area_connector.js"})
public class RichTextAreaExtension extends AbstractJavaScriptExtension {
@Override
public void extend(AbstractClientConnector connector) {
super.extend(connector);
}
}
This is the extension, then you would need to create the client side connector, which is basically a JavaScript file with a function which name is based on the package name of the extension and, of course, the extension's class name:
#!javascript
com_package_example_RichTextAreaExtension = function() {
var connectorParentId = this.getParentId();
var element = this.getElement(parentId); // this is the rich text area element, which at this point is
// If you are using jQuery, then you can just select your element like so:
var jQueryElement = $(element);
// and do whatever you would normally do with the element like
// when you are inside $(document).ready(function() {});
// or you can add a style element to the head element inside the iframe, doing something like the following:
$(element).find("iframe").contents().find('head')
.append('<link rel="stylesheet" href="./VAADIN/themes/your_theme/style_for_richtextarea_body.css" type="text/css" />');
}
And you are done. Another benefit, as you can see is that you don't have to write different code for different browsers (Mozilla, Chrome, IE), you can just use jQuery and the library will handle the compatibility for you. The last part is the extended component itself. As I said before, you can just extend Vaadin's RichTextArea:
public class RichTextAreaWithStyleOnBody extends RichTextArea {
public RichTextAreaWithStyleOnBody(String caption, Property<?> dataSource) {
super(caption);
if (dataSource != null)
setPropertyDataSource(dataSource);
new RichTextAreaExtension().extend(this);
}
public RichTextAreaWithStyleOnBody(String caption, Property<?> dataSource) {
this(caption, dataSource);
}
public RichTextAreaWithStyleOnBody(String caption) {
this(caption, null);
}
public RichTextAreaWithStyleOnBody(Property<?> dataSource) {
this(null, dataSource);
}
public RichTextAreaWithStyleOnBody() {
this(null, null);
}
}
Note the usage of the JavaScript extension inside the main constructor. And finally you can use it in your layout just as you would with any other component:
// Inside your UI's class
@Override
protected void init(VaadinRequest request) {
VerticalLayout layout = new VerticalLayout();
layout.setMargin(true);
layout.setSpacing(true);
setContent(layout);
RichTextArea rTa = new RichTextAreaWithStyleOnBody("A rich text area with a styled body");
rTa.setStyleName("myRichTextArea"); // you can do whatever you'll like on the server side just because your rich text area extends a Vaadin server side component.
rTa.setSizeFull();
layout.addComponent(rTa);
}