water-sys/app/screens/MainApp.tsx

import React, { useEffect, useState, useCallback } from 'react';
import {
  View,
  Text,
  StyleSheet,
  SafeAreaView,
  StatusBar,
  TouchableOpacity,
  Modal,
  Animated,
  Dimensions,
  BackHandler,
} from 'react-native';
import Constants from 'expo-constants';
import AsyncStorage from '@react-native-async-storage/async-storage';
import { useNavigation } from '@react-navigation/native';
import { NativeStackNavigationProp } from '@react-navigation/native-stack';
import { RootStackParamList } from '../../App';

type MainAppScreenNavigationProp = NativeStackNavigationProp<
  RootStackParamList,
  'MainApp'
>;

const MODAL_HEIGHT = 280; // 估计的模态框高度

export const MainApp = () => {
  const navigation = useNavigation<MainAppScreenNavigationProp>();
  const [modalVisible, setModalVisible] = useState(true);
  const [slideAnim] = useState(new Animated.Value(MODAL_HEIGHT));
  const [fadeAnim] = useState(new Animated.Value(0));

  useEffect(() => {
    if (modalVisible) {
      slideAnim.setValue(MODAL_HEIGHT);
      fadeAnim.setValue(0);
      Animated.parallel([
        Animated.spring(slideAnim, {
          toValue: 0,
          useNativeDriver: true,
          tension: 65,
          friction: 8,
          velocity: 0.3,
        }),
        Animated.timing(fadeAnim, {
          toValue: 1,
          duration: 200,
          useNativeDriver: true,
        })
      ]).start();
    }
  }, [modalVisible]);

  const handleCloseModal = useCallback(() => {
    Animated.parallel([
      Animated.timing(slideAnim, {
        toValue: MODAL_HEIGHT,
        duration: 200,
        useNativeDriver: true,
      }),
      Animated.timing(fadeAnim, {
        toValue: 0,
        duration: 200,
        useNativeDriver: true,
      })
    ]).start(() => {
      setModalVisible(false);
    });
  }, [slideAnim, fadeAnim]);

  const handleLoginPress = () => {
    handleCloseModal();
    // 延迟导航，等待弹窗关闭动画完成
    setTimeout(() => {
      navigation.navigate('Login');
    }, 200);
  };

  useEffect(() => {
    const backHandler = BackHandler.addEventListener(
      'hardwareBackPress',
      () => {
        if (modalVisible) {
          handleCloseModal();
          return true;
        }
        return false;
      }
    );

    return () => backHandler.remove();
  }, [modalVisible, handleCloseModal]);

  const handleLogout = async () => {
    try {
      await AsyncStorage.removeItem('@selected_country');
      navigation.replace('CountrySelect');
    } catch (error) {
      console.error('Error logging out:', error);
    }
  };

  return (
    <View style={styles.container}>
      <StatusBar
        backgroundColor="#fff"
        barStyle="dark-content"
      />
      <SafeAreaView style={styles.safeArea}>
        <View style={styles.header}>
          <Text style={styles.title}>{t('mainAppTitle')}</Text>
        </View>
        <View style={styles.content}>
          <Text style={styles.text}>{t('mainAppText')}</Text>
          <TouchableOpacity 
            style={styles.button}
            onPress={handleLogout}
          >
            <Text style={styles.buttonText}>{t('resetCountry')}</Text>
          </TouchableOpacity>
        </View>
      </SafeAreaView>

      <Modal
        visible={modalVisible}
        transparent={true}
        animationType="none"
        statusBarTranslucent={true}
        onRequestClose={handleCloseModal}
      >
        <Animated.View 
          style={[
            styles.modalContainer,
            {
              opacity: fadeAnim,
            }
          ]}
        >
          <Animated.View 
            style={[
              styles.modalOverlay,
              {
                opacity: fadeAnim,
              }
            ]}
          >
            <TouchableOpacity 
              style={styles.modalOverlayTouch}
              activeOpacity={1}
              onPress={handleCloseModal}
            />
          </Animated.View>
          <Animated.View
            style={[
              styles.modalContent,
              {
                transform: [{ translateY: slideAnim }],
              },
            ]}
          >
            <TouchableOpacity 
              style={styles.closeButton}
              onPress={handleCloseModal}
            >
              <Text style={styles.closeButtonText}>✕</Text>
            </TouchableOpacity>
            <View style={styles.modalHeader}>
              <View style={styles.modalIndicator} />
            </View>
            <Text style={styles.modalTitle}>{t('welcomeTitle')}</Text>
            <Text style={styles.modalText}>
              {t('welcomeMessage')}
            </Text>
            <TouchableOpacity 
              style={styles.modalButton}
              onPress={handleLoginPress}
            >
              <Text style={styles.modalButtonText}>{t('loginNow')}</Text>
            </TouchableOpacity>
          </Animated.View>
        </Animated.View>
      </Modal>
    </View>
  );
};

const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: '#fff',
    paddingTop: Constants.statusBarHeight,
  },
  safeArea: {
    flex: 1,
  },
  header: {
    padding: 20,
    backgroundColor: '#fff',
    borderBottomWidth: 1,
    borderBottomColor: '#f0f0f0',
  },
  title: {
    fontSize: 24,
    fontWeight: 'bold',
    color: '#000',
  },
  content: {
    flex: 1,
    padding: 20,
    alignItems: 'center',
    justifyContent: 'center',
  },
  text: {
    fontSize: 16,
    color: '#333',
    marginBottom: 30,
  },
  button: {
    backgroundColor: '#007AFF',
    paddingHorizontal: 20,
    paddingVertical: 12,
    borderRadius: 8,
  },
  buttonText: {
    color: '#fff',
    fontSize: 16,
    fontWeight: '500',
  },
  modalContainer: {
    flex: 1,
    justifyContent: 'flex-end',
  },
  modalOverlay: {
    position: 'absolute',
    top: 0,
    left: 0,
    right: 0,
    bottom: 0,
    backgroundColor: 'rgba(0, 0, 0, 0.4)',
  },
  modalOverlayTouch: {
    flex: 1,
  },
  modalContent: {
    backgroundColor: '#fff',
    borderTopLeftRadius: 20,
    borderTopRightRadius: 20,
    padding: 20,
    paddingBottom: 40,
  },
  modalHeader: {
    alignItems: 'center',
    marginBottom: 20,
  },
  modalIndicator: {
    width: 40,
    height: 4,
    backgroundColor: '#DDD',
    borderRadius: 2,
    marginVertical: 8,
  },
  modalTitle: {
    fontSize: 22,
    fontWeight: 'bold',
    marginBottom: 16,
    color: '#000',
  },
  modalText: {
    fontSize: 16,
    color: '#666',
    marginBottom: 24,
    lineHeight: 22,
  },
  modalButton: {
    backgroundColor: '#007AFF',
    paddingVertical: 14,
    borderRadius: 10,
    alignItems: 'center',
  },
  modalButtonText: {
    color: '#fff',
    fontSize: 16,
    fontWeight: '600',
  },
  closeButton: {
    position: 'absolute',
    top: 20,
    right: 20,
    width: 24,
    height: 24,
    alignItems: 'center',
    justifyContent: 'center',
    zIndex: 1,
  },
  closeButtonText: {
    fontSize: 20,
    color: '#999',
    fontWeight: '400',
  },
});