navigation页面监听器

useEffect(() => {
    // 进入页面
    const unsubscribe = navigation.addListener('focus', () => {});
    return unsubscribe;
  }, []);

useEffect(() => {
    // 离开页面
    const unsubscribe = navigation.addListener('blur', () => {});

    return unsubscribe;
  }, []);

useEffect(() => {
    // 离开页面之前，(点击goBack时调用)
    const unsubscribe = navigation.addListener('beforeRemove', () => {});

    return unsubscribe;
  }, []);

useEffect(() => {
    // 监听navigation的route状态
    const unsubscribe = navigation.addListener('state', () => {});

    return unsubscribe;
  }, []);