1

pages/main/mainlist.js

@@ -1222,10 +1222,9 @@ Page({
       OrderType:od,
     });
   },
-  //设置多选状态
+ //设置多选状态
   setMultipleOptions:function(event){
     var that=this;
-    //debugger;
     var IsMultipleOptions=event.currentTarget.dataset.index==1?true:false;  
     that.setData({
       IsMultipleOptions:IsMultipleOptions,
@@ -1240,6 +1239,8 @@ Page({
         List:list,
         SelectedCount:0,
         CanScroll:true,
+        IsShowSelectUpThis: false,
+        IsShowSelectDownThis: false
       });
     }
     else{
@@ -1256,7 +1257,9 @@ Page({
     var id=event.currentTarget.dataset.id;
     var list=that.data.List;
     var selectedCount=0;
-    //debugger;
+    var firstSelectedIndex = -1;
+    var lastSelectedIndex = -1;
+    
     for(var i=0;i<list.length;i++){
       if (isAll){
         list[i].Selected=true;
@@ -1269,13 +1272,27 @@ Page({
             list[i].Selected=false;          
         }
       }
-      if (list[i].Selected)
+      if (list[i].Selected) {
         selectedCount++;
+        if(firstSelectedIndex === -1) firstSelectedIndex = i;
+        lastSelectedIndex = i;
+      }
     }
+    
     that.setData({
       List:list,
       SelectedCount:selectedCount,
     });
+    
+    // 如果有选中的项目，检查它们的位置并决定显示哪个按钮
+    if(selectedCount > 0) {
+      that.checkSelectedItemsPosition(firstSelectedIndex, lastSelectedIndex);
+    } else {
+      that.setData({
+        IsShowSelectUpThis: false,
+        IsShowSelectDownThis: false
+      });
+    }
   },
   showMultipleOther: function (event) {
     var that = this;
@@ -1554,6 +1571,97 @@ Page({
       path: path,
     });
   },
+  // 检查选中项的位置并决定显示哪个按钮
+  checkSelectedItemsPosition: function(firstIndex, lastIndex) {
+    var that = this;
+    
+    // 使用选择器获取元素位置信息
+    var query = wx.createSelectorQuery();
+    
+    // 获取第一个选中项的位置
+    query.select('#scroll-' + firstIndex).boundingClientRect();
+    
+    // 如果有多个选中项，获取最后一个选中项的位置
+    if(firstIndex !== lastIndex) {
+      query.select('#scroll-' + lastIndex).boundingClientRect();
+    }
+    
+    // 获取屏幕高度
+    query.selectViewport().boundingClientRect();
+    
+    query.exec(function(res) {
+      if(!res || res.length < 2) return;
+      
+      var screenHeight = res[res.length - 1].height;
+      var screenMiddle = screenHeight / 2;
+      
+      var showUp = false;
+      var showDown = false;
+      
+      // 获取第一个选中项的位置
+      var firstItem = res[0];
+      
+      // 如果只有一个选中项
+      if(firstIndex === lastIndex) {
+        if(!firstItem) return;
+        
+        var itemMiddle = firstItem.top + firstItem.height / 2;
+        
+        // 如果项目在屏幕中间偏上
+        if(itemMiddle < screenMiddle) {
+          showUp = true;
+        } 
+        // 如果项目在屏幕中间偏下
+        else {
+          showDown = true;
+        }
+      } else {
+        // 有多个选中项
+        var lastItem = res[1];
+        
+        if(!firstItem || !lastItem) return;
+        
+        var firstItemMiddle = firstItem.top + firstItem.height / 2;
+        var lastItemMiddle = lastItem.top + lastItem.height / 2;
+        
+        // 如果第一个选中项在屏幕中间偏下
+        if(firstItemMiddle > screenMiddle) {
+          showDown = true;
+        }
+        
+        // 如果最后一个选中项在屏幕中间偏上
+        if(lastItemMiddle < screenMiddle) {
+          showUp = true;
+        }
+      }
+      
+      that.setData({
+        IsShowSelectUpThis: showUp,
+        IsShowSelectDownThis: showDown
+      });
+    });
+  },
+  onPageScroll:function(e){
+    let that=this;
+    setTimeout(function() {
+      if(that.data.IsMultipleOptions && that.data.SelectedCount > 0) {
+        var firstSelectedIndex = -1;
+        var lastSelectedIndex = -1;
+        var list = that.data.List;
+        
+        for(var i = 0; i < list.length; i++) {
+          if(list[i].Selected) {
+            if(firstSelectedIndex === -1) firstSelectedIndex = i;
+            lastSelectedIndex = i;
+          }
+        }
+        
+        if(firstSelectedIndex !== -1) {
+          that.checkSelectedItemsPosition(firstSelectedIndex, lastSelectedIndex);
+        }
+      }
+    }, 100);
+  },
   onShareAppMessage: function () {
     return {
       title: app.globalData.ShareTitle,