优化列表边界触发对齐的效果

src/components/VirtualList.vue

@@ -125,6 +125,7 @@ const handleScroll = debounce(() => {
 function handleMouseEnter(index) {
   if (!isKeyboardNavigating.value) {
     selectedIndex.value = index
+    // 移除滚动检查和处理，直接调用确保可见的方法
     ensureSelectedItemVisible()
   }
 }
@@ -138,23 +139,29 @@ function handleKeyDown(e) {
     if (keyboardTimer) clearTimeout(keyboardTimer)
     
     const containerTop = containerRef.value.scrollTop
-    const currentVisibleStartIndex = Math.floor(containerTop / totalItemHeight.value)
-    const currentVisibleEndIndex = currentVisibleStartIndex + visibleCount.value - 1
+    const containerHeight = containerRef.value.clientHeight
     
     if (e.key === 'ArrowUp') {
       const nextIndex = Math.max(0, selectedIndex.value - 1)
-      
-      if (nextIndex <= currentVisibleStartIndex) {
-        containerRef.value.scrollTop = nextIndex * totalItemHeight.value
-      }
       selectedIndex.value = nextIndex
+      
+      // 使用与向下相同的逻辑，计算项目顶部位置
+      const itemTop = nextIndex * totalItemHeight.value
+      
+      if (itemTop < containerTop) {
+        containerRef.value.scrollTop = itemTop
+      }
     } else {
       const nextIndex = Math.min(props.data.length - 1, selectedIndex.value + 1)
-      
-      if (nextIndex > currentVisibleEndIndex) {
-        containerRef.value.scrollTop = (nextIndex - visibleCount.value + 1) * totalItemHeight.value
-      }
       selectedIndex.value = nextIndex
+      
+      // 计算项目底部位置
+      const itemBottom = (nextIndex + 1) * totalItemHeight.value
+      const scrollBottom = containerTop + containerHeight
+      
+      if (itemBottom > scrollBottom) {
+        containerRef.value.scrollTop = itemBottom - containerHeight
+      }
     }
     
     keyboardTimer = setTimeout(() => {
@@ -169,15 +176,18 @@ function ensureSelectedItemVisible() {
   
   const containerTop = containerRef.value.scrollTop
   const containerHeight = containerRef.value.clientHeight
-  const visibleCount = Math.floor(containerHeight / totalItemHeight.value)
   
-  const currentVisibleStartIndex = Math.floor(containerTop / totalItemHeight.value)
-  const currentVisibleEndIndex = currentVisibleStartIndex + visibleCount - 1
+  // 计算项目的顶部和底部位置
+  const itemTop = selectedIndex.value * totalItemHeight.value
+  const itemBottom = (selectedIndex.value + 1) * totalItemHeight.value
+  const scrollBottom = containerTop + containerHeight
   
-  if (selectedIndex.value < currentVisibleStartIndex) {
-    containerRef.value.scrollTop = selectedIndex.value * totalItemHeight.value
-  } else if (selectedIndex.value > currentVisibleEndIndex) {
-    containerRef.value.scrollTop = (selectedIndex.value - visibleCount + 1) * totalItemHeight.value
+  if (itemTop < containerTop) {
+    // 如果项目顶部超出可视区域，滚动到顶部对齐
+    containerRef.value.scrollTop = itemTop
+  } else if (itemBottom > scrollBottom) {
+    // 如果项目底部超出可视区域，滚动到底部对齐
+    containerRef.value.scrollTop = itemBottom - containerHeight
   }
 }