I'm a new user of GWT and I'm looking for some advice concerning "theme management".
I have to make a website that can handle theme changes. What I mean is that a user can make is own theme by filling a form, then the website will automatically and dynamically changes its color to display the new ones.
I thought using a CSS sheet for all the static properties and using some GWT lines (e.g. label.getElement.getStyle.setColor(...)) to change color. But I have many "hover" properties and I think creating many MouseOverHandler is not a good idea ...
Is there a way to edit CSS sheet dynamically or a magic trick to do that ?
Thanks.
You have many options - the most straight forward (to me) is to make use of the existing CSS classes that GWT introduces. If you look at javadocs for any of the widgets GWT provides, you'll notice the CSS Style Rules section. For example, Button:
.gwt-Button
the outer element
That means that every Button you add to the page has a .gwt-Button style applied to it. If you inject a CSS stylesheet with a rule that overrides this style:
.gwtButton {
background: red;
}
All your buttons will turn red. You can inject stylesheets using StyleInjector. Creating the stylesheet's content dynamically is up to you - but it's just text, it shouldn't be hard (but make sure the generated CSS rules are valid!).
To get you started, try hooking up this code to some button and see if clicking it triggers changing all the Buttons on the page red:
StyleInjector.inject(".gwt-Button { background: red; }");
If you have custom widgets that you want styled differently, just add an individual class to them (.customWidgetWhatever, like Button has .gwt-Button, etc.) that you will include in your custom stylesheet.
Make sure you understand how CSS works and what it can do for you. For example, if you want to style each button the same, you don't have to change each button's style individually, just use:
button {
background: green;
}
And all the <button>s will turn green.
The easiest way to change themes without reloading the whole application is to assign a theme class to the body element.
You'd want to prepend each CSS class in your app with a particular theme, e.g.:
.theme1 .myClass {
color: red;
}
.theme2 .myClass {
color: blue;
}
Then you'll apply a particular theme to the body element:
<body class="theme1">
When you want to change themes, you'll have to change the body class so it will become:
<body class="theme2">
this way, each element that has class myClass will have its color changed from red to blue.
You cannot edit a CSS file dynamically, but you can inject CSS style either as a new CSS file, or directly into your document.
For example, you can define all key CSS rules in your "main.css" file, and add your user-defined rules directly into the host HTML page with a style tag.
Related
Vaadin flow theming and styles confuse me. Is there a way to disable it and apply natural css. I know how to reference a css file inside vaadin, and use setClassName but I would prefer to use ordinary css style for components.
Thank you
You can override the default lumo styling by providing yours. For instance, to remove the background color from a ComboBox, I can target the input as follows in a CSS file named vaadin-combo-box.css:
[part="input-field"] {
background-color: var(--lumo-base-color);
max-width: fit-content;
}
To set the colors for a disabled button, you can target it as follows:
filename: vaadin-button.css
code:
:host([theme~='primary'][disabled]) {
background-color: red;
}
And you get the following:
To change the primary color or any other global styling, explore your styles.css file.
For a better understanding, take a look at this video https://vaadin.com/learn/training/v14-theming
Like with all other styling you need to check the states / attributes of the component while the specific state is active and check the DOM - only caveat would be that you need to add those style in the specific files like vaadin-button.css to be applied inside the shadow DOM.
Is there a way or operator in CSS to assign a new style to specific element? I don't want to change original style because it belongs to a plugin and changing it will change it on all my pages. However I want to change the position of the element on a specific web page.
I also can't call those styles in my html because that CSS file is used solely in jquery plugin, you only put class="slideshow" in html div and thats that. I can change that CSS file to suit my preferences, however I don't know how to change it for specific instances?
In order to make a specific styling on a specific instance of your plugin, you should assign a specific class or id to a parent container of that plugin for the instance you need customization.
Example : you can give the id="special" to a parent of the plugin in the page you want customization.
Then you can use that selector to style it independently from other instances of that same plugin.
example CSS:
#special .slideshow /*other selectors */ {
/*your specific style */
}
In your scenario CSS specificity Rule will be helpful for you.
For example in your plugin you are using RED Font Color in class slideshow. Then in your another CSS file you can create a more specific Rule.
Check the Demo what I've posted above on comments section. Here is the direct link.
div.slider .slideshow {color:green;}
You can refer to the element by name:
#htmlitemname{
color: green;
}
CSS is cascading, i.e. it will apply it top down - general, class and then the id.
You can add !important to your css if you wish it to override any inline styles. So long as you make a style sheet specifically for that page, this should work for what you need. Hope this helps :)
I am using Active Admin, is there a way to override CSS used by the active admin theme?
For eg:- I have to change css of submit button which is disabled to cursor: wait; and make it unclickable.
What's the best way to do this?
just make a new file
app/assets/stylesheets/active_admin.css.scss
and put your scss code there.
(Or just active_admin.css with css code)
You can override any CSS property by overriding the CSS class or IDs in you own stylesheet with !important attribute if you do not have any access to the original stylesheet
For example, use
.submit-button {
color: white !important;
}
to change the color of the submit button text.
It is easy to change the styles in Rails 4. Go to
app/assets/stylesheets/active_admin.css.scss
OR (depending upon where you have kept the file)
vendor/assets/stylesheets/active_admin.css.scss
and add styles in there.
I put my form classes in a container class to create a more specific reference. Like..
.form-container {
font-family: 'open-sans';
width: 420px;
.text-field-class {
input{border:none; border-bottom: 1px;}
}
}
this is working so far... for the most part. Better than important. Though maybe using an ID would be the more appropriate way.
I have a GWT application,
I created appBlueTheme.jar,appOrangeTheme.jar and added to BuildPath of project.
My module.gwt.xml file has
....
<inherits name='appBlueTheme.appBlueTheme'/>
<inherits name='appOrangeTheme.appOrangeTheme'/>
...
But in my app i see the effect of appBlueTheme as GWT doc say
"inherited modules will be cascaded in the order they are listed"
I want theme to be changed based on user response.
How do i achieve this?
If by "theme" you mean styling, the right approach is not to create a separate jar for each theme, but to use CSS instead.
A. If you use CSSResource, you can use conditional CSS:
https://developers.google.com/web-toolkit/doc/latest/DevGuideClientBundle#Conditional_CSS
B. If you use an external CSS file, instead of
.headerPanel {
background: blue;
}
you can specify a different background based on a theme selected:
.orangeTheme .headerPanel {
background: orange;
}
.blueTheme .headerPanel {
background: blue;
}
Note that your code (or Ui:Binder) should only assign class "headerPanel" to a widget. When you start your app, you assign a default theme to your outmost widget (the one you add to the RootPanel). For example, you set
myAppPanel.addStyleName("blueTheme");
This will give a blue background to all widgets with "headerPanel" class. When a user chooses a different theme, you remove "blueTheme" class and add "orangeTheme" class. It will automatically refresh the page (no need to reload it) and all styles will change.
EDIT:
If you need to apply a theme to the entire app, including PopupPanel and dialogs, use this code to apply your theme:
Document.get().getBody().setClassName("blueTheme");
I am using the jQuery UI library out of the box, based on a theme.
Having links rendered as buttons is great, however I need to override some buttons with different colours.
How do I specify an specific class for a particular button to use?
I recommend looking at the CSS for the jQuery UI buttons and duplicating the structure of the CSS which specifies the buttons, but with your own class instead of the jQuery UI classes. Make the overrides that you need in this CSS and include it after the jQuery UI CSS. CSS uses a combination of the most specific selector and ordering to determine which values to apply. By doing this you will make sure that you have the same specificity for each of the CSS selectors used by jQuery so that your CSS takes precedence based on order.
Smashing Magazine has an article that probably has more information than you care to know about the specificity issue.
You can also:
Use Developer Tools in the browser (Chrome has great ones).
See what class from jQuery UI defines the button color.
Override it in your CSS file with the "!important" attribute.
For example, when I needed to override jQuery UI spinner control and remove the borders, I found the class that defines the borders using Chrome Dev Tools. Then in CSS: I added something like that:
.<jquery-ui-class-that-i-found> { border: 0px !important; }
Works great!
I would say, give the particular button or buttons an id, and:
$("#buttonId").removeClass().addClass("myClass");
If you want to apply it to multiple buttons each with its own id:
$("#buttonId, #anotherButton").removeClass().addClass("myClass");
I think the button API should include a configuration like this where you can change color etc. by passing parameters
$("button").button({background:"FFFFFF",hover:"FFFFF"});
this is just an idea where you can change some of its visual attributes.
I found this worked for me:
$(".btnSave").removeClass("ui-state-default").addClass("SaveButtonStyling");
Basically needed to remove the ui-state-default class and then add my own for the background colour etc.
Thsi meant that the rounded corner class etc stayed put and I was able to amend the background colour etc.
If you simply wish to have some additional/different for particular buttons, simply give the buttons some classes like class="mybuttonclass otherbuttonclass" - multiple classes are allowed. Then, just add css rules for your class(es)
.mybuttonclass
{
background-color: red;
}
.otherbuttonclass
{
color:white;
}
thus the background is red with white text - or whatever combination you wish, which would override items in the cascade (CSS) above it. (assumption is that your .CSS file is linked in AFTER the jquery UI css file, or is in-line on the page, both of which would override the jQuery UI css.