AppbarHeader.js

/* @flow */

import * as React from 'react';
import { View, Platform, SafeAreaView, StyleSheet } from 'react-native';

import Appbar, { DEFAULT_APPBAR_HEIGHT } from './Appbar';
import { withTheme } from '../../core/theming';
import type { Theme } from '../../types';

type Props = React.ElementConfig<typeof Appbar> & {|
  /**
   * Whether the background color is a dark color. A dark header will render light text and vice-versa.
   */
  dark?: boolean,
  /**
   * Extra padding to add at the top of header to account for translucent status bar.
   * This is automatically handled on iOS >= 11 including iPhone X using `SafeAreaView`.
   * If you are using Expo, we assume translucent status bar and set a height for status bar automatically.
   * Pass `0` or a custom value to disable the default behaviour, and customize the height.
   */
  statusBarHeight?: number,
  /**
   * Content of the header.
   */
  children: React.Node,
  /**
   * @optional
   */
  theme: Theme,
  style?: any,
|};

const DEFAULT_STATUSBAR_HEIGHT_EXPO =
  global.__expo && global.__expo.Constants
    ? global.__expo.Constants.statusBarHeight
    : 0;
const DEFAULT_STATUSBAR_HEIGHT = Platform.select({
  android: DEFAULT_STATUSBAR_HEIGHT_EXPO,
  ios: Platform.Version < 11 ? DEFAULT_STATUSBAR_HEIGHT_EXPO : 0,
});

/**
 * A component to use as a header at the top of the screen.
 * It can contain the screen title, controls such as navigation buttons, menu button etc.
 *
 * <div class="screenshots">
 *   <figure>
 *     <img class="medium" src="screenshots/appbar-header.android.png" />
 *     <figcaption>Android</figcaption>
 *   </figure>
 *   <figure>
 *     <img class="medium" src="screenshots/appbar-header.ios.png" />
 *     <figcaption>iOS</figcaption>
 *   </figure>
 * </div>
 *
 * ## Usage
 * ```js
 * import * as React from 'react';
 * import { Appbar } from 'react-native-paper';
 *
 * export default class MyComponent extends React.Component {
 *   _goBack = () => console.log('Went back');
 *
 *   _onSearch = () => console.log('Searching');
 *
 *   _onMore = () => console.log('Shown more');
 *
 *   render() {
 *     return (
 *       <Appbar.Header>
 *         <Appbar.BackAction
 *           onPress={this._goBack}
 *         />
 *         <Appbar.Content
 *           title="Title"
 *           subtitle="Subtitle"
 *         />
 *         <Appbar.Action icon="search" onPress={this._onSearch} />
 *         <Appbar.Action icon="more-vert" onPress={this._onMore} />
 *       </Appbar.Header>
 *     );
 *   }
 * }
 * ```
 */
class AppbarHeader extends React.Component<Props> {
  static displayName = 'Appbar.Header';

  render() {
    const {
      // Don't use default props since we check it to know whether we should use SafeAreaView
      statusBarHeight = DEFAULT_STATUSBAR_HEIGHT,
      style,
      ...rest
    } = this.props;

    const { colors } = rest.theme;
    const {
      height = DEFAULT_APPBAR_HEIGHT,
      elevation = 4,
      backgroundColor = colors.primary,
      ...restStyle
    } = StyleSheet.flatten(style) || {};

    // Let the user override the behaviour
    const Wrapper =
      typeof this.props.statusBarHeight === 'number' ? View : SafeAreaView;

    return (
      <Wrapper style={[{ backgroundColor, elevation }]}>
        {/* $FlowFixMe: There seems to be conflict between Appbar's props and Header's props */}
        <Appbar
          style={[
            { height, backgroundColor, marginTop: statusBarHeight },
            styles.appbar,
            restStyle,
          ]}
          {...rest}
        />
      </Wrapper>
    );
  }
}

const styles = StyleSheet.create({
  appbar: {
    elevation: 0,
  },
});

export default withTheme(AppbarHeader);