添加下滑自动收缩侧边栏按钮功能

pages/index/index.js

@@ -1127,6 +1127,9 @@ Page({
     const threshold = 50;
     const backToTopThreshold = 300;
     
+    const lastScrollTop = this.data.lastScrollTop || 0;
+    const isScrollingDown = scrollTop > lastScrollTop;
+    
     let needUpdate = false;
     const updates = {
       lastScrollTop: scrollTop
@@ -1135,7 +1138,15 @@ Page({
     // 搜索框始终固定显示，不做隐藏处理
     
     // 侧边栏按钮显示逻辑
-    if (scrollTop <= threshold && this.data.sidebarBtnHidden) {
+    // 下滑时隐藏按钮（除非用户未手动隐藏过且在顶部）
+    if (isScrollingDown && scrollTop > threshold && !this.data.sidebarBtnHidden) {
+      updates.sidebarBtnHidden = true;
+      needUpdate = true;
+      wx.setStorageSync('sidebarBtnHidden', true);
+      wx.setStorageSync('userManuallyHidden', true);
+    }
+    // 上滑到顶部时显示按钮
+    else if (scrollTop <= threshold && this.data.sidebarBtnHidden && !this.data.userManuallyHidden) {
       updates.sidebarBtnHidden = false;
       needUpdate = true;
       wx.setStorageSync('sidebarBtnHidden', false);