主题

styled-component提供<ThemeProvider>包装组件以支持主题.<ThemeProvider>通过contextAPI 为其后代组件提供主题.在其渲染树中的所有组件都能够访问主题.

下面的示例通过创建一个按钮组件来说明如何传递主题:

// Define our button, but with the use of props.theme this time
const Button = styled.button`
  font-size: 1em;
  margin: 1em;
  padding: 0.25em 1em;
  border-radius: 3px;

  /* Color the border and text with theme.main */
  color: ${props => props.theme.main};
  border: 2px solid ${props => props.theme.main};
`;

// We are passing a default theme for Buttons that arent wrapped in the ThemeProvider
Button.defaultProps = {
  theme: {
    main: "palevioletred"
  }
}

// Define what props.theme will look like
const theme = {
  main: "mediumseagreen"
};

render(
  <div>
    <Button>Normal</Button>
    <ThemeProvider theme={theme}>
      <Button>Themed</Button>
    </ThemeProvider>
  </div>
);

函数主题

theme prop 也可以传递一个函数.该函数接收渲染树上级<ThemeProvider>所传递的主题. 通过这种方式可以使 themes 形成上下文.

下面的示例说明了如何通过第二个<ThemeProvider>来交换 background和foreground的颜色. 函数invertTheme 接收上级 theme 后创建一个新的 theme.

// Define our button, but with the use of props.theme this time
const Button = styled.button`
  color: ${props => props.theme.fg};
  border: 2px solid ${props => props.theme.fg};
  background: ${props => props.theme.bg};

  font-size: 1em;
  margin: 1em;
  padding: 0.25em 1em;
  border-radius: 3px;
`;

// Define our `fg` and `bg` on the theme
const theme = {
  fg: "palevioletred",
  bg: "white"
};

// This theme swaps `fg` and `bg`
const invertTheme = ({ fg, bg }) => ({
  fg: bg,
  bg: fg
});

render(
  <ThemeProvider theme={theme}>
    <div>
      <Button>Default Theme</Button>

      <ThemeProvider theme={invertTheme}>
        <Button>Inverted Theme</Button>
      </ThemeProvider>
    </div>
  </ThemeProvider>
);

在styled-components外使用主题

如果需要在styled-components外使用主题,可以使用高阶组件withTheme:

import { withTheme } from 'styled-components'

class MyComponent extends React.Component {
  render() {
    console.log('Current theme: ', this.props.theme)
    // ...
  }
}

export default withTheme(MyComponent)

theme prop

主题可以通过theme prop传递给组件.通过使用theme prop可以绕过或重写ThemeProvider所提供的主题.

// Define our button
const Button = styled.button`
  font-size: 1em;
  margin: 1em;
  padding: 0.25em 1em;
  border-radius: 3px;

  /* Color the border and text with theme.main */
  color: ${props => props.theme.main};
  border: 2px solid ${props => props.theme.main};
`;

// Define what main theme will look like
const theme = {
  main: "mediumseagreen"
};

render(
  <div>
    <Button theme={{ main: "royalblue" }}>Ad hoc theme</Button>
    <ThemeProvider theme={theme}>
      <div>
        <Button>Themed</Button>
        <Button theme={{ main: "darkorange" }}>Overidden</Button>
      </div>
    </ThemeProvider>
  </div>
);