Do I really need to put css resource file into a ClientBundle in GWT?

StackOverflow https://stackoverflow.com/questions/11124350

  •  15-06-2021
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Question

I want to put all my resources into a ClientBundle for easy management. So I first started working on putting a single css file, which is also the file under /war directory, into ClinetBundle. However the style cannot be rendered in my output, but if I just put the css file under /war without ever using the css ClientBundle, the program worked just fine.

Below is my simple test case (using ClientBundle) - I put the css file same folder in the client package and remove css file under /war directory: 

import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.core.client.GWT;
import com.google.gwt.resources.client.ClientBundle;
import com.google.gwt.resources.client.CssResource;
import com.google.gwt.resources.client.CssResource.NotStrict;
import com.google.gwt.user.client.Window;
import com.google.gwt.user.client.ui.RootPanel;
import com.smartgwt.client.widgets.layout.HLayout;
import com.smartgwt.client.widgets.layout.VLayout;

public class Test implements EntryPoint {

    private static final int REPORT_TITLE_HEIGHT = 50;
    public static final MyResources INSTANCE = GWT.create(MyResources.class);

    public interface MyResources extends ClientBundle {
        @NotStrict
        @Source("Test.css")
        CssResource css();
    }

    public void onModuleLoad() {

        INSTANCE.css().ensureInjected();

        Window.enableScrolling(false);
        Window.setMargin("0px");

        VLayout vl = new VLayout();
        vl.setWidth100();
        vl.setHeight100();

        HLayout reportTitleBar = new HLayout();
        reportTitleBar.setHeight(REPORT_TITLE_HEIGHT);
        reportTitleBar.setStyleName("report-title-bar");

        vl.setMembers(reportTitleBar);

        RootPanel.get().add(vl);
    }
}

The style cannot be rendered.

Another simple case - without using css ClientBundle and put back the css file into /war folder. 

import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.user.client.Window;
import com.google.gwt.user.client.ui.RootPanel;
import com.smartgwt.client.widgets.layout.HLayout;
import com.smartgwt.client.widgets.layout.VLayout;

public class Test implements EntryPoint {

    private static final int REPORT_TITLE_HEIGHT = 50;

    public void onModuleLoad() {

        Window.enableScrolling(false);
        Window.setMargin("0px");

        VLayout vl = new VLayout();
        vl.setWidth100();
        vl.setHeight100();

        HLayout reportTitleBar = new HLayout();
        reportTitleBar.setHeight(REPORT_TITLE_HEIGHT);
        reportTitleBar.setStyleName("report-title-bar");

        vl.setMembers(reportTitleBar);

        RootPanel.get().add(vl);
    }
}

The style can be correctly rendered.

And my Test.css code: 

.report-title-bar {
    /* IE10 Consumer Preview */
    background-image: -ms-linear-gradient(top left, #FFFFFF 0%, #00A3EF 100%);
    /* Mozilla Firefox */
    background-image: -moz-linear-gradient(top left, #FFFFFF 0%, #00A3EF 100%);
    /* Opera */
    background-image: -o-linear-gradient(top left, #FFFFFF 0%, #00A3EF 100%);
    /* Webkit (Safari/Chrome 10) */
    background-image: -webkit-gradient(linear, left top, right bottom, color-stop(0, #FFFFFF), color-stop(1, #00A3EF));
    /* Webkit (Chrome 11+) */
    background-image: -webkit-linear-gradient(top left, #FFFFFF 0%, #00A3EF 100%);
}

What is the issue here, anyone please shed me some light on it. Appreciated!

Was it helpful?

Solution

If you put your css files into a clientbundle your css files have to be parsed by the GWT Compilers CSS Parser, which currently bases on an old version which is somewhat a little hacked. (This is going to change in the future though)

For the parser to work you need to escape your background values like this:

background-image: literal('-webkit-linear-gradient(top left, #FFFFFF 0%, #00A3EF 100%)');

There are some other quirks that also need escaping. Take a look in the docs and search for escaping: https://developers.google.com/web-toolkit/doc/latest/DevGuideClientBundle

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