react-native中使用ScrollView组件自己封装走马灯

Orenda ·

更新时间:2024-11-13

· 719 次阅读

使用ScrollView替代View可以实现安全范围内的滚动

showsVerticalScrollIndicator隐藏滚动条

制作轮播图

import {
  View,
  Text,
  StatusBar,
  SafeAreaView,
  StyleSheet,
  ScrollView,
  Image,
  Dimensions,
} from 'react-native';
const screenWidth = Math.round(Dimensions.get('window').width);
const App = () => {
  const scrollRef = useRef();
  const [currentIndex, setCurrentIndex] = useState(0);
  useEffect(() => {
    //初始化后，页面渲染完，立即滚动到真正的第一页
    setTimeout(() => {
      scrollRef.current.scrollTo({x: screenWidth, y: 0, animated: false});
    }, 0);
  }, [scrollRef]);
  useEffect(() => {
    scrollRef.current.currentIndex = currentIndex;
  }, [currentIndex, scrollRef]);
  //定时器，定时滚动
  useEffect(() => {
    console.log('初始化了定时器');
    setInterval(() => {
      const offset = screenWidth * (scrollRef.current.currentIndex + 2);
      scrollRef.current.scrollTo({x: offset, y: 0, animated: true});
    }, 3000);
  }, [scrollRef]);
  const scrollEnd = useCallback(event => {
    let index = event.nativeEvent.contentOffset.x / screenWidth;
    // index = Math.round(index);
    // console.log(index);
    if (index === 0) {
      setCurrentIndex(() => 3);
      //这是最后一页，应该去到真实的最后一页
      const offset = screenWidth * images.length;
      scrollRef.current.scrollTo({x: offset, y: 0, animated: false});
    } else if (index === 5) {
      setCurrentIndex(() => 0);
      //这是第一页
      const offset = screenWidth;
      scrollRef.current.scrollTo({x: offset, y: 0, animated: false});
    } else {
      setCurrentIndex(() => index - 1);
    }
  }, []);
  return (


              {/* 假的最后一张 */}
              {/* 真实的内容 */}
              {images.map((item, index) => (
              ))}
              {/* 假的第一张 */}
          {currentIndex}
  );
};

样式：

const S = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: '#f1f1f1',
    overflow: 'hidden',
  },
  content: {
    flex: 1,
    backgroundColor: 'red',
  },
  scroll: {
    width: '100%',
    height: 200,
    backgroundColor: '#fff',
  },
  scrollWrap: {
    width: '600%',
    height: 200,
    flexDirection: 'row',
  },
  image: {
    width: (1 / 6) * 100 + '%',
    height: 200,
  },
});

作者：Georgia fab

封装 native 走马灯 scrollview React

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