Could not find Angular Material core theme. Most Material components may not work as expected. For more info refer to the theming guide: https://material.angular.io/guide/theming

Hi! Ciao! How Are You???

Bug, feature request, or proposal:

Could not find Angular Material core theme, although all core @include mat-core(); is included. I got 6 themes, all working except the warning.

What is the expected behavior?

No warning.

What is the current behavior?

Warning.

What are the steps to reproduce?

git clone https://github.com/patrikx3/corifeus-app-web-pages.git
cd corifeus-app-web-pages
yarn install
grunt run

See.

What is the use-case or motivation for changing an existing behavior?

Themes.

Which versions of Angular, Material, OS, browsers are affected?

Current.

Is there anything else we should know?

Nope.

[MikeInSwitzerland]

This issue tied me in knots, but eventually, I realised that what Angular’s own Materials tutorial doesn’t tell us is that we must include this line in the “styles.css” file, to make the controls appear normally (certainly in Windows 7).

@import “…/node_modules/@angular/material/prebuilt-themes/deeppurple-amber.css”;

Trying to include that file using an “include”, even in the index.html file, failed miserably for me. It could never locate this .css file… even if I manually copied it into the same folder as index.html.

[siebmanb]

@sharpevo thanks a lot for your help. I had the issue when running tests using karma. Your fix does not work for this use case, however adding the theme file in karma.conf.js as follows fixes the issue

files: [
            {pattern: './src/test.ts', watched: false},
            'node_modules/@angular/material/prebuilt-themes/deeppurple-amber.css'
        ],