@jamsch/react-native-hanzi-writer

Hanzi/Kanji writer and stroke order quizzer library for React Native, based on the vanilla JS hanzi-writer library.

Prerequisites

Make sure you have the following packages installed in your project before continuing:

• react-native-gesture-handler@^2.8.0
• react-native-reanimated@^2.12.0
• react-native-svg@^13.4.0

Installation

# Peer dependencies required for this library to function
npm install react-native-gesture-handler@^2.8.0
npm install react-native-reanimated@^2.12.0
npm install react-native-svg@^13.4.0

# Install this library
npm install @jamsch/react-native-hanzi-writer

Basic Usage

import { Button, Text, View } from 'react-native';
import { GestureHandlerRootView } from 'react-native-gesture-handler';
import { HanziWriter, useHanziWriter } from '@jamsch/react-native-hanzi-writer';

function App() {
  const writer = useHanziWriter({
    character: '验',
    // (Optional) This is where you would load the character data from a CDN
    loader(char) {
      return fetch(
        `https://cdn.jsdelivr.net/npm/[email protected]/${char}.json`
      ).then((res) => res.json());
    },
  });

  return (
    <GestureHandlerRootView style={{ flex: 1 }}>
      <HanziWriter
        writer={writer}
        // Optional, render out your loading UI
        loading={<Text>Loading...</Text>}
        // Optional, render out an error UI in case the fetch call fails
        error={
          <View>
            <Text>Error loading character. </Text>
            <Button title="Refetch" onPress={writer.refetch} />
          </View>
        }
        style={{ alignSelf: 'center' }}
      >
        {/** Optional, grid lines to help draw the character */}
        <HanziWriter.GridLines color="#ddd" />
        <HanziWriter.Svg>
          {/** The outline is laid under the character */}
          <HanziWriter.Outline color="#ccc" />
          {/** The character is displayed on top. Animations run here. Quizzing will hide it */}
          <HanziWriter.Character color="#555" radicalColor="green" />
          {/** Quiz strokes display after every correct stroke in quiz mode */}
          <HanziWriter.QuizStrokes />
          {/** The mistake highligher will animate and fade out a stroke in quiz mode */}
          <HanziWriter.QuizMistakeHighlighter
            color="#539bf5"
            strokeDuration={400}
          />
        </HanziWriter.Svg>
      </HanziWriter>
    </GestureHandlerRootView>
  );
}

Important Notes

• Make sure your entire application is wrapped in a <GestureHandlerRootView> element for gestures to work in quiz mode.
• Make sure that the order of the elements inside <HanziWriter.Svg> match the above example as it affects the display layering. That being said, you still can conditionally render these components.

Starting the quiz

You can start the quiz by calling writer.quiz.start().

• To listen for state changes (such as the current stroke index, or whether the quiz is active), use writer.quiz.useStore(selector)
• To listen for specific quiz events (such as completed, correct stroke, mistakes), attach them as arguments to writer.quiz.start().

import { HanziWriter, useHanziWriter } from '@jamsch/react-native-hanzi-writer';

function App() {
  const writer = useHanziWriter({ character: '验' });

  const quizActive = writer.quiz.useStore((s) => s.active);

  const startQuiz = () => {
    writer.quiz.start({
      /** Optional. Default: 1. This can be set to make stroke grading more or less lenient. Closer to 0 the more strictly strokes are graded. */
      leniency: 1,
      /** Optional. Default: 0. */
      quizStartStrokeNum: 0,
      /** Highlights correct stroke (uses <QuizMistakeHighlighter />) after incorrect attempts. Set to `false` to disable. */
      showHintAfterMisses: 2,
      onComplete({ totalMistakes }) {
        console.log(
          `Quiz complete! You made a total of ${totalMistakes} mistakes`
        );
      },
      onCorrectStroke() {
        console.log('onCorrectStroke');
      },
      onMistake(strokeData) {
        console.log('onMistake', strokeData);
      },
    });
  };

  return (
    <GestureHandlerRootView style={{ flex: 1 }}>
      <HanziWriter writer={writer}>
        {/** Include all the HanziWriter.XXX components here */}
      </HanziWriter>
      <Button
        onPress={quizActive ? writer.quiz.stop : startQuiz}
        title={quizActive ? 'Stop Quiz' : 'Start Quiz'}
      />
    </GestureHandlerRootView>
  );
}

Animating strokes

Running stroke order animations is simple.

• Call writer.animator.animateCharacter() with optional arguments to control stroke duration, delays between strokes.
• Call writer.animator.cancelAnimation() to cancel the running animation.
• Use writer.animator.useStore(selector) to listen for changes to the animation state.

import { HanziWriter, useHanziWriter } from '@jamsch/react-native-hanzi-writer';

function App() {
  const writer = useHanziWriter({ character: '验' });

  const animatorState = writer.animator.useStore((s) => s.state);

  return (
    <GestureHandlerRootView style={{ flex: 1 }}>
      <HanziWriter writer={writer}>
        {/** Include all the HanziWriter.XXX components here */}
      </HanziWriter>
      <Button
        onPress={() => {
          if (animatorState === 'playing') {
            writer.animator.cancelAnimation();
          } else {
            writer.animator.animateCharacter({
              /** Optional. Default: 1000ms */
              delayBetweenStrokes: 800,
              /** Optional. Default: 400ms */
              strokeDuration: 800,
              /** Optional. */
              onComplete() {
                console.log('Animation complete!');
              },
            });
          }
        }}
        title={
          animatorState === 'playing' ? 'Stop animating' : 'Animate Strokes'
        }
      />
    </GestureHandlerRootView>
  );
}

Contributing

See the contributing guide to learn how to contribute to the repository and the development workflow.

License

MIT