I'm using MDL lite with Halogen. MDL relies mostly on CSS, but it adds some JS for various features.
This has the unfortunate consequences when used with VDom approach. For example, the textfield applies is-dirty class after input had been modified - this, amongst other things, makes the label text not visible (it's displayed similarily to placeholder in the input field by default).
My rendering code is unaware of that, and when it rerenders, this class is dropped, resulting in the label displayed on top of input value.
My immediate solution to this is that I can recreate some of that logic in my components, adding this class as needed. Are there any other approaches? Can we somehow tell the VDom renderer to not touch some elements?
Related
I'm intermediate in my Angular understanding and am trying to wrap my head around how to accomplish the following.
I want to create a UI component that can be used to contain heterogeneous content, likely from other components.
It displays a certain amount of the content with an overflow ellipsis affordance.
It has a full border and a header.
The issue is that due to the border and functionality, I want this component to contain the content controlled by some other component.
I've looked at inheritance, directives, and manipulating the view container. Each solution looks is intuitively displeasing as is either impossible or would seem to place a heavy load on the DOM render.
Use
Read detailed tutorial at http://toddmotto.com/transclusion-in-angular-2-with-ng-content
I have been trying to disable scroll bars in a text area using the code:
ScrollBar scrollBarv = (ScrollBar)textArea.lookup(".scroll-bar:vertical");
scrollBarv.setDisable(true);
But all I get is a null pointer for "scrollBarv". What am I missing?
You can't disable a scroll bar in a text area via lookups like you are trying to do.
A lookup is CSS based, which usually means it will only work after a CSS application pass has been applied. Generally, for a lookup to work as expected, a layout pass also needs to be applied on the parent node or scene. The logic in the JavaFX layout handlers for complex nodes such as controls may modify the CSS and nodes for the controls.
To understand how to apply CSS and perform a layout pass, read the relevant applyCss() documentation.
So you could do this:
textArea.applyCss();
textArea.layout();
ScrollBar scrollBarv = (ScrollBar)textArea.lookup(".scroll-bar:vertical");
scrollBarv.setDisable(true);
But even then, it would not do what you want. Because it is just a one-time call. If the user types new text into an empty TextArea until it fills the area, then a scroll bar will show up, and if the user deletes text in the text area, the scroll bar will be removed. And the new scroll bar which shows up wouldn't be found when you did your lookup because it would not have existed at that time.
Generally, the preferred alternative to performing lookups to nodes is to apply CSS style classes with the style class defining the desired attributes of the node regardless of the state it is in (and using psuedo-classes if state based CSS definitions are required). However, that probably won't work in this case as I can't see a definition for a disable attribute in the JavaFX CSS reference guide. Perhaps you might manage what you need via the visibility property, though that is unlikely as visibility is a bit different from disable.
The behavior for controlling the scroll bars is internally coded in the TextAreaSkin (which in Java 8 is not part of the public JavaFX API). You could copy or subclass the TextAreaSkin to customize its behavior and then attach your customized skin to your node. This is really the "proper" way to customize internal control behavior in the way in which you wish. A discussion of the detailed steps to achieve this is outside the scope of this answer.
But, in the end, I'm not sure how useful the behavior you desire is. Rather than disabling the vertical scroll bar, you could just disable the entire TextArea, which would be fine for most similar use-cases. Though, perhaps your use-case is different somehow in requiring only the vertical scroll bar to be disabled.
I've been searching for a while for an answer to this problem and I'm rather surprised that I have not found a solution. I'm working with Qt on Mac and would like to customize QPushbuttons and other QWidgets, but I want to maintain the native look somewhat as well. For example, if I want to remove the margins of a QButton using style sheets, I do:
QPushButton btn(this);
...
btn.setStyleSheet("margin:0;");
This indeed removes the margins, but it also removes the native style already set for default buttons. Of course, I just want to modify margins using style sheets, how do I do this?
Also, I would expect that btn.styleSheet() would return the native style sheet, but it is blank by default. Only when I set my own style sheet, does it return a valid value, but only for the property I set. I get that setStyleSheet would reset the style sheet, but how do I modify certain properties and leave everything else as is?
TL;DR: It can't be done that way.
The native style cannot be generally expressed as a CSS style sheet, thus styleSheet() is empty by default on all styles. Thus, unfortunately, it's not possible to change native style elements one-by-one, since typically they are drawn by the platform APIs that allow little if any customization.
For examples, a QPushButton is drawn by the native calls on both OS X and Windows.
In the specific case of the margin, though, you can easily work around by creating a proxy style that returns smaller control rectangle and crops and transforms the painter before passing it to the base style. This also works for colorization/color substitution etc. You basically have to accept that the base style has to do the drawing, and then it's up to you to tweak it.
I want to change the background color of my Vaadin app on the valueChange event of a OptionGroup component.
As there are a fairly big number of layouts on my page, what would be the best is to change every HorizontalLayout and VerticalLayout background-color, but every new component that could be added should have this color too.
How can I achieve that? Thanks.
Two approaches come to mind.
The simplest, conceptually, as well as in terms of implementation, would be to have a single component to serve as the background, and give your HorizontalLayout and VerticalLayout components a transparent background. If you're layout is too complex for this, you can have a number of base 'background' components, again, with your layout components on top being transparent. The idea is to reduce the components whose color you need to change to something manageable.
If that approach doesn't translate to your use case, you can always use JavaScript to select the layout components on the fly and redefine their background. This could be made more manageable by giving all the layout components a common CSS class (eg: 'dynamic-background').
JavaScript.getCurrent().execute("$('.dynamic-background').css('background-color', 'purple')");
Note that this JavaScript depends on JQuery, have a look around for more details on integrating JQuery with Vaadin:
Add javascript/Jquery & client side code in Vaadin 7
Integrating HTML and JavaScript in Vaadin 7
I am using Flex 4.9. I thought that with the newest SDK, they finally made Flex and CSS components tags to work. But they did not.
I tried to set horisontalAlign and verticalAlign of spark HGroup vie CSS style, so I could manage it smoothly and save some code typing. HGroups didnt respond to CSS style I applied, ok, I thought that at least I will set their width. It also did not work! Nor pixel width or percent value.
Does Flex CSS styling is really so limited or am I missing something?
horizontalAlign, verticalAlign, width and height are all properties of the HGroup class, not styles. Hence you cannot set these properties through stylesheets.
What you seem to be missing is that Flex is not HTML and that the same semantics do not apply. In Flex 4 we separate the content from the way it is presented mainly through a process called skinning: we declare components and their logic in one class (usually in ActionScript) and we define its visual representation in another (usually written in MXML).
With this separation already in place there is hardly any need for stylesheets. In fact, if you would put a CSS on top of that, you would kind of artificially try to separate the layout into two separate entities which doesn't make much sense. Not to mention it would make the code much harder to read.
There is a case where CSS comes in handy though, that is when you want to apply a certain visual style throughout your application. A Button could have five different skins, but through CSS you could set the font color of all five to a specific color without repeating that in each skin.