digital-pilates/app/(tabs)/_layout.tsx

import * as Haptics from 'expo-haptics';
import { Tabs, usePathname } from 'expo-router';
import React from 'react';
import { Text, TouchableOpacity, View } from 'react-native';

import { IconSymbol } from '@/components/ui/IconSymbol';
import { Colors } from '@/constants/Colors';
import { ROUTES } from '@/constants/Routes';
import { TAB_BAR_BOTTOM_OFFSET, TAB_BAR_HEIGHT } from '@/constants/TabBar';
import { useColorScheme } from '@/hooks/useColorScheme';

export default function TabLayout() {
  const theme = (useColorScheme() ?? 'light') as 'light' | 'dark';
  const colorTokens = Colors[theme];
  const pathname = usePathname();

  return (
    <Tabs
      initialRouteName="coach"
      screenOptions={({ route }) => {
        const routeName = route.name;
        const isSelected = (routeName === 'explore' && pathname === ROUTES.TAB_EXPLORE) ||
          (routeName === 'coach' && pathname === ROUTES.TAB_COACH) ||
          (routeName === 'goals' && pathname === ROUTES.TAB_GOALS) ||
          (routeName === 'statistics' && pathname === ROUTES.TAB_STATISTICS) ||
          pathname.includes(routeName);

        return {
          headerShown: false,
          tabBarActiveTintColor: colorTokens.tabIconSelected,
          tabBarButton: (props) => {
            const { onPress } = props;

            const handlePress = (event: any) => {
              if (process.env.EXPO_OS === 'ios') {
                Haptics.impactAsync(Haptics.ImpactFeedbackStyle.Light);
              }
              onPress && onPress(event);
            };

            // 基于 routeName 设置图标与标题，避免 tabBarIcon 的包装导致文字裁剪
            const getIconAndTitle = () => {
              switch (routeName) {
                case 'explore':
                  return { icon: 'magnifyingglass.circle.fill', title: '发现' } as const;
                case 'coach':
                  return { icon: 'person.3.fill', title: 'Seal' } as const;
                case 'goals':
                  return { icon: 'flag.fill', title: '目标' } as const;
                case 'statistics':
                  return { icon: 'chart.pie.fill', title: '统计' } as const;
                case 'personal':
                  return { icon: 'person.fill', title: '个人' } as const;
                default:
                  return { icon: 'circle', title: '' } as const;
              }
            };

            const { icon, title } = getIconAndTitle();
            const activeContentColor = colorTokens.onPrimary;
            const inactiveContentColor = colorTokens.tabIconDefault;

            return (
              <TouchableOpacity
                onPress={handlePress}
                accessibilityRole="button"
                style={{
                  flex: 1,
                  alignItems: 'center',
                  justifyContent: 'center',
                  flexDirection: 'row',
                  marginHorizontal: 6,
                  marginVertical: 10,
                  borderRadius: 25,
                  backgroundColor: isSelected ? colorTokens.tabBarActiveBackground : 'transparent',
                  paddingHorizontal: isSelected ? 16 : 10,
                  paddingVertical: 8,
                }}
              >
                <View style={{ flexDirection: 'row', alignItems: 'center' }}>
                  <IconSymbol
                    size={22}
                    name={icon as any}
                    color={isSelected ? activeContentColor : inactiveContentColor}
                  />
                  {isSelected && !!title && (
                    <Text
                      style={{
                        color: activeContentColor,
                        fontSize: 12,
                        fontWeight: '600',
                        marginLeft: 6,
                      }}
                      // 选中态下不限制行数，避免大屏布局下被裁剪成省略号
                      numberOfLines={0 as any}
                    >
                      {title}
                    </Text>
                  )}
                </View>
              </TouchableOpacity>
            );
          },
          tabBarStyle: {
            position: 'absolute',
            bottom: TAB_BAR_BOTTOM_OFFSET,
            height: TAB_BAR_HEIGHT,
            borderRadius: 34,
            backgroundColor: colorTokens.tabBarBackground,
            shadowColor: '#000',
            shadowOffset: { width: 0, height: 2 },
            shadowOpacity: 0.2,
            shadowRadius: 10,
            elevation: 5,
            paddingHorizontal: 10,
            paddingTop: 0,
            paddingBottom: 0,
            marginHorizontal: 20,
            width: '90%',
            alignSelf: 'center',
          },
          tabBarItemStyle: {
            backgroundColor: 'transparent',
            height: TAB_BAR_HEIGHT,
            marginTop: 0,
            marginBottom: 0,
            paddingTop: 0,
            paddingBottom: 0,
          },
          tabBarShowLabel: false,
        };
      }}>

      <Tabs.Screen
        name="coach"
        options={{
          title: 'Seal',
          tabBarIcon: ({ color }) => {
            const isCoachSelected = pathname === '/coach';
            return (
              <View style={{ flexDirection: 'row', alignItems: 'center' }}>
                <IconSymbol size={22} name="person.3.fill" color={color} />
                {isCoachSelected && (
                  <Text
                    numberOfLines={1}
                    style={{
                      color: color,
                      fontSize: 12,
                      fontWeight: '600',
                      marginLeft: 6,
                      textAlign: 'center',
                      flexShrink: 0,
                    }}>
                    Seal
                  </Text>
                )}
              </View>
            );
          },
        }}
      />
      <Tabs.Screen
        name="explore"
        options={{
          title: '发现',
          href: null,
          tabBarIcon: ({ color }) => {
            const isHomeSelected = pathname === '/' || pathname === '/index';
            return (
              <View style={{ flexDirection: 'row', alignItems: 'center' }}>
                <IconSymbol size={22} name="magnifyingglass.circle.fill" color={color} />
                {isHomeSelected && (
                  <Text
                    numberOfLines={1}
                    style={{
                      color: color,
                      fontSize: 12,
                      fontWeight: '600',
                      marginLeft: 6,
                      textAlign: 'center',
                      flexShrink: 0,
                    }}>
                    发现
                  </Text>
                )}
              </View>
            );
          },
        }}
      />

      <Tabs.Screen
        name="statistics"
        options={{
          title: '统计',
          tabBarIcon: ({ color }) => {
            const isStatisticsSelected = pathname === '/statistics';
            return (
              <View style={{ flexDirection: 'row', alignItems: 'center' }}>
                <IconSymbol size={22} name="chart.pie.fill" color={color} />
                {isStatisticsSelected && (
                  <Text
                    numberOfLines={1}
                    style={{
                      color: color,
                      fontSize: 12,
                      fontWeight: '600',
                      marginLeft: 6,
                      textAlign: 'center',
                      flexShrink: 0,
                    }}>
                    统计
                  </Text>
                )}
              </View>
            );
          },
        }}
      />
      <Tabs.Screen
        name="goals"
        options={{
          title: '目标',
          tabBarIcon: ({ color }) => {
            const isGoalsSelected = pathname === '/goals';
            return (
              <View style={{ flexDirection: 'row', alignItems: 'center' }}>
                <IconSymbol size={22} name="flag.fill" color={color} />
                {isGoalsSelected && (
                  <Text
                    numberOfLines={1}
                    style={{
                      color: color,
                      fontSize: 12,
                      fontWeight: '600',
                      marginLeft: 6,
                      textAlign: 'center',
                      flexShrink: 0,
                    }}>
                    目标
                  </Text>
                )}
              </View>
            );
          },
        }}
      />
      <Tabs.Screen
        name="personal"
        options={{
          title: '个人',
          tabBarIcon: ({ color }) => {
            const isPersonalSelected = pathname === '/personal';
            return (
              <View style={{ flexDirection: 'row', alignItems: 'center' }}>
                <IconSymbol size={22} name="person.fill" color={color} />
                {isPersonalSelected && (
                  <Text
                    numberOfLines={1}
                    style={{
                      color: color,
                      fontSize: 12,
                      fontWeight: '600',
                      marginLeft: 6,
                      textAlign: 'center',
                      flexShrink: 0,
                    }}>
                    个人
                  </Text>
                )}
              </View>
            );
          },
        }}
      />
    </Tabs>
  );
}