React Native 之组件的定义

import Hello from ‘./Hello‘ 
export default class App extends Component {

  render(){
    return (
      <View>
        <Hello name="你伟哥"/>
      </View>
    );
  }
  
}

// 函数式写法 无状态 不能用this
function App(props) {
  return <Text style={{fontSize:20,backgroundColor:‘red‘,marginTop:50}}>Hello.{props.name}</Text>
}
module.exports=App;

const App = () => {
  return (
    <Fragment>
      <StatusBar barStyle="dark-content" />
      <SafeAreaView>
        <ScrollView
          contentInsetAdjustmentBehavior="automatic"
          style={styles.scrollView}>
          <Header />
          {global.HermesInternal == null ? null : (
            <View style={styles.engine}>
              <Text style={styles.footer}>Engine: Hermes</Text>
            </View>
          )}
          <View style={styles.body}>
            <View style={styles.sectionContainer}>
              <Text style={styles.sectionTitle}>Step One</Text>
              <Text style={styles.sectionDescription}>
                Edit <Text style={styles.highlight}>App.js</Text> to change this
                screen and then come back to see your edits.
              </Text>
            </View>
            <View style={styles.sectionContainer}>
              <Text style={styles.sectionTitle}>See Your Changes</Text>
              <Text style={styles.sectionDescription}>
                <ReloadInstructions />
              </Text>
            </View>
            <View style={styles.sectionContainer}>
              <Text style={styles.sectionTitle}>Debug</Text>
              <Text style={styles.sectionDescription}>
                <DebugInstructions />
              </Text>
            </View>
            <View style={styles.sectionContainer}>
              <Text style={styles.sectionTitle}>Learn More</Text>
              <Text style={styles.sectionDescription}>
                Read the docs to discover what to do next:
              </Text>
            </View>
            <LearnMoreLinks />
          </View>
        </ScrollView>
      </SafeAreaView>
    </Fragment>
  );
};

const styles = StyleSheet.create({
  scrollView: {
    backgroundColor: Colors.lighter,
  },
  engine: {
    position: ‘absolute‘,
    right: 0,
  },
  body: {
    backgroundColor: Colors.white,
  },
  sectionContainer: {
    marginTop: 32,
    paddingHorizontal: 24,
  },
  sectionTitle: {
    fontSize: 24,
    fontWeight: ‘600‘,
    color: Colors.black,
  },
  sectionDescription: {
    marginTop: 8,
    fontSize: 18,
    fontWeight: ‘400‘,
    color: Colors.dark,
  },
  highlight: {
    fontWeight: ‘700‘,
  },
  footer: {
    color: Colors.dark,
    fontSize: 12,
    fontWeight: ‘600‘,
    padding: 4,
    paddingRight: 12,
    textAlign: ‘right‘,
  },
});

export default App;