react-native-scroll-into-view

react-native-scroll-into-view

Scroll a ReactNative View ref into the visible portion of a ScrollView.

Similar to DOMElement.scrollIntoView() for web, with some extras.

yarn add react-native-scroll-into-view
// or
npm install react-native-scroll-into-view --save

There is no native code: this library is compatible with Expo managed workflow.

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Why ?

On long scrollable forms, can ensure errors become visible to the user on submit:

Building some kind of "sections index":

But really you are free to build whatever you want with it

Features:

• Declarative component API
• Imperative hook API
• Configurable at many levels
• Different alignment modes
• Insets
• Typescript definitions
• Support for composition/refs/other ScrollView wrappers (Animated.ScrollView, react-native-keyboard-aware-scroll-view, glamorous-native...)

Note we don't plan to support anything else than ScrollView. Virtualized lists generally offer methods to scroll to a given index.

Minimal hooks example

import { View, Text, ScrollView } from 'react-native';
import {
  wrapScrollView,
  useScrollIntoView,
} from 'react-native-scroll-into-view';

const CustomScrollView = wrapScrollView(ScrollView);

function MyScreen() {
  return (
    <CustomScrollView>
      <MyScreenContent />
    </CustomScrollView>
  );
}

function MyScreenContent() {
  const scrollIntoView = useScrollIntoView();
  const viewRef = useRef();
  return (
    <>
      <Button onPress={() => scrollIntoView(viewRef.current)}>
        Scroll a view ref into view
      </Button>
      // in android if the scroll is not working then add renderToHardwareTextureAndroid this to view
      <View style={{ height: 100000 }}>
        <Text>Some long ScrollView content</Text>
      </View>

      <View ref={viewRef}>
        <Text>Will be scrolled into view on button press</Text>
      </View>
    </>
  );
}

API

import {
  ScrollIntoView, // enhanced View container
  wrapScrollView, // simple wrapper, no config
  wrapScrollViewConfigured, // complex wrapper, takes a config
  useScrollIntoView, // access hook for imperative usage
} from 'react-native-scroll-into-view';

// Available options with their default value
const options = {
  // auto: ensure element appears fully inside the view (if not already inside). It may align to top or bottom.
  // top: align element to top
  // bottom: align element to bottom
  // center: align element at the center of the view
  align: 'auto',

  // Animate the scrollIntoView() operation
  animated: true,

  // By default, scrollIntoView() calls are throttled a bit because it does not make much sense
  // to scrollIntoView() 2 elements at the same time (and sometimes even impossible)
  immediate: false,

  // Permit to add top/bottom insets so that element scrolled into view
  // is not touching directly the borders of the scrollview (like a padding)
  insets: {
    top: 0,
    bottom: 0,
  },

  // Advanced: use these options as escape hatches if the lib default functions do not satisfy your needs
  computeScrollY: (scrollViewLayout, viewLayout, scrollY, insets, align) => {},
  measureElement: viewRef => {},
};

// Wrap the original ScrollView
const CustomScrollView = wrapScrollView(ScrollView);

// Use the wrapped CustomScrollView as a replacement of ScrollView
function MyScreen() {
  return (
    <CustomScrollView
      // Can provide default options (overrideable)
      scrollIntoViewOptions={scrollIntoViewOptions}
    >
      <ScreenContent />
    </CustomScrollView>
  );
}

// Implement ScreenContent (inner of the ScrollView) with the useScrollIntoView and refs
function ScreenContent() {
  const scrollIntoView = useScrollIntoView();
  const viewRef = useRef();

  return (
    <>
      <Button
        onPress={() => {
          scrollIntoView(viewRef.current, options);
        }}
      >
        Scroll a view ref into view
      </Button>

      <View style={{ height: 100000 }}>
        <Text>Some long ScrollView content</Text>
      </View>

      <View ref={viewRef}>
        <Text>Will be scrolled into view on button press</Text>
      </View>
    </>
  );
}

// Or implement ScreenContent (inner of the ScrollView) with class + declarative ScrollIntoView component
class ScreenContent extends React.Component {
  render() {
    return (
      <>
        <ScrollIntoView>
          <Text>This will scroll into view on mount</Text>
        </ScrollIntoView>

        <ScrollIntoView align="center">
          <Text>This will scroll into view on mount and will be centered</Text>
        </ScrollIntoView>

        <ScrollIntoView animated={false}>
          <Text>This will scroll into view on mount without any animation</Text>
        </ScrollIntoView>

        <ScrollIntoView immediate={true}>
          <Text>
            This will not throttle scrollIntoView calls, as by default it does
            not make much sense to scroll into view multiple elements at the
            same time...
          </Text>
        </ScrollIntoView>

        <ScrollIntoView enabled={false}>
          <Text>This will scroll into view whenever enabled becomes true</Text>
        </ScrollIntoView>

        <ScrollIntoView scrollIntoViewKey="some string">
          <Text>
            This will scroll into view whenever scrollIntoViewKey changes
          </Text>
        </ScrollIntoView>

        <ScrollIntoView
          onMount={false}
          onUpdate={true}
          scrollIntoViewKey="some string"
        >
          <Text>
            This will scroll into on update (if it becomes enabled, or key
            changes)
          </Text>
        </ScrollIntoView>

        <ScrollIntoView scrollIntoViewOptions={options}>
          <Text>
            This will scroll into view on mount with custom option props
          </Text>
        </ScrollIntoView>

        <View>
          <ScrollIntoView
            enabled={false}
            ref={ref => (this.scrollIntoViewRef = ref)}
          >
            <Text>This will scroll into view when the button is pressed</Text>
          </ScrollIntoView>
          <Button
            title="Make above text scroll into view with custom options"
            onPress={() =>
              this.scrollIntoViewRef.scrollIntoView(scrollIntoViewOptions)
            }
          />
        </View>
      </>
    );
  }
}

You can also configure the HOC:

const CustomScrollView = wrapScrollViewConfigured({
  // SIMPLE CONFIG:
  // ScrollIntoView default/fallback options
  options: scrollIntoViewOptions,

  // ADVANCED CONFIG:
  // Use this if you use a ScrollView wrapper that does not use React.forwardRef()
  refPropName: 'ref',
  // unwraps the ref that the wrapped ScrollView gives you (this lib need the bare metal ScrollView ref)
  getScrollViewNode: ref => ref,
  // fallback value for throttling, can be overriden by user with props
  scrollEventThrottle: 16,
})(ScrollView);

All these hoc configurations can also be provided to the CustomScrollView as props.

Demos:

You can run the example folder as an Expo app with yarn start

It is also published on Expo

Recipes

Using in forms:

The integration with form libraries like Formik and Redux-form is very simple (see Formik example)

• By default, the first error field of the form will reveal itself
• enabled={!!error} means we'll only scroll into view fields that have an error
• scrollIntoViewKey={submitCount} means we'll scroll into view fields which still have errors on every Formik submit attempt (submitCount is provided by Formik)

Using with react-native-keyboard-aware-scroll-view

KeyboardAwareScrollView does not forward refs by default so we need to obtain ref by using the innerRef prop:

const ScrollIntoViewScrollView = wrapScrollViewConfigured({
  refPropName: 'innerRef',
})(KeyboardAwareScrollView);

TODOs:

• Tests
• Universal/Web support
• Support horizontal ScrollView?

Contribute

If your changes are impactful, please open an issue first.

License

MIT

Some code is inspired from contribution of @sebasgarcep of an initial scrollIntoView support for react-native-keyboard-aware-scroll-view

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