Tuesday, December 31, 2013

Re: JavaFX 2.2 WebView support - possible new User Agent?

Here are the Jira issues that I mentioned that affect select elements:

https://javafx-jira.kenai.com/browse/RT-33717
https://javafx-jira.kenai.com/browse/RT-16078

Please vote for them if you think that you may ever consider using the JavaFX WebView.

On Monday, December 30, 2013 9:37:52 PM UTC-5, Michael Prentice wrote:
Yep, we've seen those issues. As I mentioned, I've submitted + voted for a number of select element related bugs. I can try to post links to the bugs in Oracle's Jira tomorrow. Mouse wheel is supposed to be implemented in Java 8. All of the others were pushed out of Java 8 and are currently marked as Java 9. But with enough support, they might be patched in Java 8 after GA.

I'd like to hear about any other issues that you've run into. So far the lacking select element has been the primary pain point for us. 

We've been able to make alert and confirm dialogs work with a small amount of code beyond their examples. Of course we'll try to use GWT DialogBoxes for most things (which are working well), but Activities and Places relies on the confirm dialog.

Michael Prentice
GDG Space Coast

On Monday, December 30, 2013 6:59:08 PM UTC-5, Gary Eberhart wrote:
Hello Michael,

I'm having issues with WebView as well. I'm displaying GWT, Grails and PrimeFaces pages in a WebView. I've found several serious functional problems running these web pages in WebView. One of the easiest to explain are the Dropdowns (select elements) that take all available space on the screen, and worse yet do not default to the value of the text. For example I have a drop down for year. The text is 2013 and when you click on the drop down the resulting list starts at 1913 requiring the user to use the little scroll button to get back to 2013. It's just one thing after another. I too have a huge Swing application, 2000 views, that I want to migrate to Web technologies over the next 10 years.

I'd be happy to completely document all of my issues with pictures and all upon request. Please tell me I'm wrong, but it appears WebView fails to render web pages correctly that are otherwise rendered flawlessly by the major browsers?





On Tuesday, November 5, 2013 2:44:13 PM UTC-7, Michael Prentice wrote:
I've been working on a project for the last few months which involves creating new screens for our Swing application. We wanted to start moving towards a web based interface, but we cannot re-do hundreds of screens in a single release/year. So after doing some testing and being satisfied with the HTML5 / CSS 2.1 support in the JavaFX 2.2 Webview, we decided that this was a possible migration path. I am currently working on the first leg of this path and things have gone quite well so far. I chose GWT to build the front-end of the app due to our team's experience with WindowBuilder/Swing and it's focus on Enterprise web applications. Our application is a complex Enterprise app that must be maintained over many years by different people. 

Here are some of the results and issues:

Success:
  • General GWT development has been very productive (learning and architecting the app took considerable time).
  • Performance running in the WebView has been acceptable on machines with decent GPUs which includes all of our client machines (8 MB video card servers don't do well).
  • We have been able to implement communication to/from GWT<->JavaScript<->JavaFX<->Swing without any major issues and with very minimal code (some simple JSNI and JSON serialization).
  • Performance of passing data and opening/closing windows between GWT<->...<->Swing has been very good. Note that we aren't passing large data sets over 1 MB.
  • The new GWT app fits into our Swing application and feels very nearly 'just like another screen' due to GWT's out of the box styling.
  • GWT's out of the box styling has worked great and impressed our customers without us having to put forth much effort.

Issues:
  • The JavaFX WebView does not quite behave like other browsers. It uses the Safari (chrome, webkit) user agent. 
  • Drop downs (ListBox) have rounded edges (unlike Chrome) which we don't really like.
  • Drop downs (select elements) are not very usable in the WebView. They can't be styled. They show as many elements as fit on the window (extending beyond the borders of the app). Scrolling these drops downs with the mouse wheel isn't supported until JavaFX 8. I've opened some bugs for these issues with Oracle.
  • Buttons get rounded edges if we override the default GWT style.
  • Alignment between Chrome and the WebView does not match up for some elements. This causes a number of layout issues.
  • JavaFX WebView does not support CSS3 and has some of its own rules with vendor extensions of "-fx-". This includes things like "JavaFX CSS does not support CSS layout properties such as float, position, overflow, and width."
  • "CSS padding and margins properties are supported on some" objects. I tried to use a "padding-left: 22px" today which worked fine in Chrome but had no effect on the same Label in the WebView.
  • Asking Oracle for fixes or enhancements appears to involve a significantly long wait, even if quickly approved, you may not see your issue resolved for 6-18+ months. It seems to be possible to fix issues yourself via the OpenJDK project, but it appears to require significant time and effort just to get setup/approved to do this.
Now so far none of these issues have been a complete show stopper. But after running into the padding issue today and researching, it seemed like this might be the time to at least attempt to request (I know it is likely not interesting or high priority to most people) a user agent for the JavaFX WebView since it appears to need special handling to work properly (which appears to be one main goals of GWT - to eliminate the troubles of supporting multiple browsers).

I found out that JavaFX has their own CSS rules including a special "-fx-label-padding" rule. There does not appear to be anything like padding-left or padding-top, so you need to specify all 4 ("if a set of four padding values is specified, they are used for the top, right, bottom, and left edges of the region, in that order."). I added this to my existing rule which already has the "padding-left: 22px" rule. 

.foo-bar-values {
padding-left: 22px;
-fx-label-padding: 0px 0px 0px 22px;
}

Chrome handled things fine in DevMode (ignored the unknown rule with a warning). But when I loaded up the WebView version, it had no effect. I thought that this was quite odd, so I debugged it with FireBug Lite and apparently that specific CSS rule isn't there in the CSS on the page. I checked my .css file in the .WAR and it is there. Strange...

For more information on how JavaFX WebView handles CSS and defines its own CSS rules see here: http://docs.oracle.com/javafx/2/api/javafx/scene/doc-files/cssref.html

Has anyone else looked into this at all?

Does anyone have any pointers for making GWT/JavaFX play nice together for these 'vendor' extended CSS rules?


Thank you,

Michael Prentice
GDG Space Coast

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