feat: implement back button logic — single tap to scroll to top, double tap to exit.

app/index.tsx

@@ -1,5 +1,5 @@
 import React, { useEffect, useCallback, useRef, useState } from "react";
-import { View, StyleSheet, ActivityIndicator, FlatList, Pressable, Animated, StatusBar, Platform } from "react-native";
+import { View, StyleSheet, ActivityIndicator, FlatList, Pressable, Animated, StatusBar, Platform, BackHandler, ToastAndroid } from "react-native";
 import { useSafeAreaInsets } from "react-native-safe-area-context";
 import { ThemedView } from "@/components/ThemedView";
 import { ThemedText } from "@/components/ThemedText";
@@ -53,6 +53,41 @@ export default function HomeScreen() {
     }, [refreshPlayRecords])
   );
 
+    // 双击返回退出逻辑（只限当前页面）
+  const backPressTimeRef = useRef<number | null>(null);
+  const exitToastShownRef = useRef(false); // 防止重复显示提示
+
+  useFocusEffect(
+    useCallback(() => {
+    const handleBackPress = () => {
+      const now = Date.now();
+
+      // 如果还没按过返回键，或距离上次超过2秒
+      if (!backPressTimeRef.current || now - backPressTimeRef.current > 2000) {
+        backPressTimeRef.current = now;
+        ToastAndroid.show("再按一次返回键退出", ToastAndroid.SHORT);
+        return true; // 拦截返回事件，不退出
+      }
+
+      // 两次返回键间隔小于2秒，退出应用
+      BackHandler.exitApp();
+      return true;
+    };
+
+    // 仅限 Android 平台启用此功能
+    if (Platform.OS === "android") {
+      const backHandler = BackHandler.addEventListener("hardwareBackPress", handleBackPress);
+
+      // 返回首页时重置状态
+      return () => {
+        backHandler.remove();
+        backPressTimeRef.current = null;
+        exitToastShownRef.current = false;
+      };
+    }
+  }, [])
+);
+
   // 统一的数据获取逻辑
   useEffect(() => {
     if (!selectedCategory) return;

components/CustomScrollView.tsx

@@ -1,5 +1,5 @@
-import React, { useCallback } from "react";
-import { View, StyleSheet, ScrollView, ActivityIndicator } from "react-native";
+import React, { useCallback, useRef, useState, useEffect } from "react";
+import { View, StyleSheet, ScrollView, ActivityIndicator, TouchableOpacity, BackHandler } from "react-native";
 import { ThemedText } from "@/components/ThemedText";
 import { useResponsiveLayout } from "@/hooks/useResponsiveLayout";
 import { getCommonResponsiveStyles } from "@/utils/ResponsiveStyles";
@@ -20,7 +20,7 @@ interface CustomScrollViewProps {
 const CustomScrollView: React.FC<CustomScrollViewProps> = ({
   data,
   renderItem,
-  numColumns, // 现在可选，如果不提供将使用响应式默认值
+  numColumns,
   loading = false,
   loadingMore = false,
   error = null,
@@ -29,8 +29,27 @@ const CustomScrollView: React.FC<CustomScrollViewProps> = ({
   emptyMessage = "暂无内容",
   ListFooterComponent,
 }) => {
+  const scrollViewRef = useRef<ScrollView>(null);
+  const firstCardRef = useRef<any>(null); // <--- 新增
+  const [showScrollToTop, setShowScrollToTop] = useState(false);
   const responsiveConfig = useResponsiveLayout();
   const commonStyles = getCommonResponsiveStyles(responsiveConfig);
+  const { deviceType } = responsiveConfig;
+
+  // 添加返回键处理逻辑
+  useEffect(() => {
+    if (deviceType === 'tv') {
+      const backHandler = BackHandler.addEventListener('hardwareBackPress', () => {
+        if (showScrollToTop) {
+          scrollToTop();
+          return true; // 阻止默认的返回行为
+        }
+        return false; // 允许默认的返回行为
+      });
+
+      return () => backHandler.remove();
+    }
+  }, [showScrollToTop,deviceType]);
 
   // 使用响应式列数，如果没有明确指定的话
   const effectiveColumns = numColumns || responsiveConfig.columns;
@@ -40,6 +59,9 @@ const CustomScrollView: React.FC<CustomScrollViewProps> = ({
       const { layoutMeasurement, contentOffset, contentSize } = nativeEvent;
       const isCloseToBottom = layoutMeasurement.height + contentOffset.y >= contentSize.height - loadMoreThreshold;
 
+      // 显示/隐藏返回顶部按钮
+      setShowScrollToTop(contentOffset.y > 200);
+
       if (isCloseToBottom && !loadingMore && onEndReached) {
         onEndReached();
       }
@@ -47,6 +69,14 @@ const CustomScrollView: React.FC<CustomScrollViewProps> = ({
     [onEndReached, loadingMore, loadMoreThreshold]
   );
 
+  const scrollToTop = () => {
+    scrollViewRef.current?.scrollTo({ y: 0, animated: true });
+    // 滚动动画结束后聚焦第一个卡片
+    setTimeout(() => {
+      firstCardRef.current?.focus();
+    }, 500); // 500ms 适配大多数动画时长
+  };
+
   const renderFooter = () => {
     if (ListFooterComponent) {
       if (React.isValidElement(ListFooterComponent)) {
@@ -124,47 +154,72 @@ const CustomScrollView: React.FC<CustomScrollViewProps> = ({
       width: responsiveConfig.cardWidth,
       marginRight: responsiveConfig.spacing,
     },
+    scrollToTopButton: {
+      position: 'absolute',
+      right: responsiveConfig.spacing,
+      bottom: responsiveConfig.spacing * 2,
+      backgroundColor: 'rgba(0, 0, 0, 0.6)',
+      padding: responsiveConfig.spacing,
+      borderRadius: responsiveConfig.spacing,
+      opacity: showScrollToTop ? 1 : 0,
+    },
   });
 
   return (
-    <ScrollView
-      contentContainerStyle={dynamicStyles.listContent}
-      onScroll={handleScroll}
-      scrollEventThrottle={16}
-      showsVerticalScrollIndicator={responsiveConfig.deviceType !== 'tv'}
-    >
-      {data.length > 0 ? (
-        <>
-          {rows.map((row, rowIndex) => {
-            const isFullRow = row.length === effectiveColumns;
-            const rowStyle = isFullRow ? dynamicStyles.fullRowContainer : dynamicStyles.partialRowContainer;
+    <View style={{ flex: 1 }}>
+      <ScrollView
+        ref={scrollViewRef}
+        contentContainerStyle={dynamicStyles.listContent}
+        onScroll={handleScroll}
+        scrollEventThrottle={16}
+        showsVerticalScrollIndicator={responsiveConfig.deviceType !== 'tv'}
+      >
+        {data.length > 0 ? (
+          <>
+            {rows.map((row, rowIndex) => {
+              const isFullRow = row.length === effectiveColumns;
+              const rowStyle = isFullRow ? dynamicStyles.fullRowContainer : dynamicStyles.partialRowContainer;
 
-            return (
-              <View key={rowIndex} style={[dynamicStyles.rowContainer, rowStyle]}>
-                {row.map((item, itemIndex) => {
-                  const actualIndex = rowIndex * effectiveColumns + itemIndex;
-                  const isLastItemInPartialRow = !isFullRow && itemIndex === row.length - 1;
-                  const itemStyle = isLastItemInPartialRow ? dynamicStyles.itemContainer : dynamicStyles.itemWithMargin;
+              return (
+                <View key={rowIndex} style={[dynamicStyles.rowContainer, rowStyle]}>
+                  {row.map((item, itemIndex) => {
+                    const actualIndex = rowIndex * effectiveColumns + itemIndex;
+                    const isLastItemInPartialRow = !isFullRow && itemIndex === row.length - 1;
+                    const itemStyle = isLastItemInPartialRow ? dynamicStyles.itemContainer : dynamicStyles.itemWithMargin;
 
-                  return (
-                    <View key={actualIndex} style={isFullRow ? dynamicStyles.itemContainer : itemStyle}>
-                      {renderItem({ item, index: actualIndex })}
-                    </View>
-                  );
-                })}
-              </View>
-            );
-          })}
-          {renderFooter()}
-        </>
-      ) : (
-        <View style={commonStyles.center}>
-          <ThemedText>{emptyMessage}</ThemedText>
-        </View>
+                    const cardProps = {
+                      key: actualIndex,
+                      style: isFullRow ? dynamicStyles.itemContainer : itemStyle,
+                    };
+
+                    return (
+                      <View {...cardProps}>
+                        {renderItem({ item, index: actualIndex })}
+                      </View>
+                    );
+                  })}
+                </View>
+              );
+            })}
+            {renderFooter()}
+          </>
+        ) : (
+          <View style={commonStyles.center}>
+            <ThemedText>{emptyMessage}</ThemedText>
+          </View>
+        )}
+      </ScrollView>
+      {deviceType!=='tv' && (
+        <TouchableOpacity
+          style={dynamicStyles.scrollToTopButton}
+          onPress={scrollToTop}
+          activeOpacity={0.8}
+        >
+          <ThemedText>⬆️</ThemedText>
+        </TouchableOpacity>
       )}
-    </ScrollView>
+    </View>
   );
-
 };
 
 export default CustomScrollView;