fix(ui): TabBar 点击滑块从旧位置滑到新位置

- 点击时不再让滑块在 touchstart 直接跳到手指位置
- 拖动超过 12px 阈值后才跟手，位置统一用百分比，避免 px/calc 混用导致跳变
- 松手按命中 tab 切页，同一 tab 不重复跳转

dist/custom-tab-bar/index.js

@@ -1 +1 @@
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+"use strict";(wx["webpackJsonp"]=wx["webpackJsonp"]||[]).push([[777],{7914:function(n,e,t){var a=t(7842),c=t(5544),r=t(118),u=t(758),i=t.n(u),o=t(6540),s=t(1457),l=t(9703),f=t(6606),h=t(8199);function g(n,e,t){return Number.isFinite(n)?Math.min(t,Math.max(e,n)):e}function v(n){return g(n,0,100)}function d(n,e){return!Number.isFinite(n)||e<=0?0:g(Math.floor(v(n)/100*e),0,e-1)}function m(n,e,t){return Math.abs(e-n)>=t}function p(n){var e=n/750;return{left:36*e,width:Math.max(0,n-72*e)}}var b=t(4848),x=[{pagePath:"/pages/index/index",label:"\u9996\u9875",icon:(0,h.uq)("/icon/\u9996\u9875.svg"),iconActive:(0,h.uq)("/icon/\u9996\u9875-fill.svg")},{pagePath:"/pages/shop/index",label:"\u5546\u54c1",icon:(0,h.uq)("/icon/\u5546\u54c1.svg"),iconActive:(0,h.uq)("/icon/\u5546\u54c1-fill.svg")},{pagePath:"/pages/designList/index",label:"\u8bbe\u8ba1\u6e05\u5355",icon:(0,h.uq)("/icon/\u8c03\u8272\u76d8.svg"),iconActive:(0,h.uq)("/icon/\u8c03\u8272\u76d8-fill.svg")},{pagePath:"/pages/orders/index",label:"\u8ba2\u5355",icon:(0,h.uq)("/icon/\u5305\u88f9.svg"),iconActive:(0,h.uq)("/icon/\u5305\u88f9-fill.svg")},{pagePath:"/pages/profile/index",label:"\u6211\u7684",icon:(0,h.uq)("/icon/\u4e2a\u4eba.svg"),iconActive:(0,h.uq)("/icon/\u4e2a\u4eba-fill.svg")}],C=100/x.length,S=12;function P(n){var e=x.findIndex(function(e){return n.endsWith(e.pagePath)});return x[e>=0?e:0].pagePath}function q(){var n=i().getCurrentInstance().router,e=n&&n.path?n.path:"pages/index/index";return P(e)}function N(){var n=(0,o.useState)((0,s.eW)((0,s.O4)())),e=(0,c.A)(n,2),t=e[0],a=e[1],u=(0,o.useState)(q),h=(0,c.A)(u,2),g=h[0],N=h[1],T=(0,o.useState)(null),w=(0,c.A)(T,2),j=w[0],A=w[1],M=(0,o.useRef)(null),E=(0,o.useRef)(0),I=(0,o.useRef)(null);(0,o.useEffect)(function(){var n=function(n){return a(n)};return i().eventCenter.on(l.Wo,n),function(){i().eventCenter.off(l.Wo,n)}},[]),(0,o.useEffect)(function(){var n=function(n){!n||"dark"!==n.theme&&"light"!==n.theme||((0,s.Rq)(n.theme),"auto"===(0,s.O4)()&&a(n.theme))},e=i();return e.onThemeChange&&e.onThemeChange(n),function(){e.offThemeChange&&e.offThemeChange(n)}},[]),(0,o.useEffect)(function(){var n=function(n){var e=i().getCurrentInstance().router,t=e&&e.path?e.path:"pages/index/index";N(P(n||t))};return i().eventCenter.on("tabBarChange",n),function(){i().eventCenter.off("tabBarChange",n)}},[]),(0,o.useEffect)(function(){(0,f.G)(t)},[t]);var W=function(n){N(P(n)),i().switchTab({url:n}),i().eventCenter.trigger("tabBarChange",n)},O=function(n){var e=n.touches&&n.touches[0];if(e){var t=p(i().getSystemInfoSync().windowWidth);I.current=t,E.current=e.clientX,M.current=null,A(null)}},R=function(n){var e=I.current,t=n.touches&&n.touches[0];if(e&&t&&(null!==M.current||m(E.current,t.clientX,S))){var a=v((t.clientX-e.left)/e.width*100);M.current=a,A(a)}},X=function(n){var e=I.current;if(e){var t;if(null!==M.current)t=d(M.current,x.length);else{var a=n.changedTouches&&n.changedTouches[0],c=a?a.clientX:E.current;t=d(v((c-e.left)/e.width*100),x.length)}var r=x[t];r&&r.pagePath!==g&&W(r.pagePath),I.current=null,E.current=0,M.current=null,A(null)}},k=function(){I.current=null,E.current=0,M.current=null,A(null)},y=Math.max(0,x.findIndex(function(n){return n.pagePath===g}));return(0,b.jsxs)(r.Ss,{className:"tab-bar-root theme-".concat(t),children:[(0,b.jsx)(r.Ss,{className:"tab-bar-gradient"}),(0,b.jsxs)(r.Ss,{className:"custom-tab-bar theme-".concat(t),onTouchStart:O,onTouchMove:R,onTouchEnd:X,onTouchCancel:k,catchMove:!0,children:[(0,b.jsx)(r.Ss,{className:"tab-bar-caustic"}),(0,b.jsx)(r.Ss,{className:"tab-bar-rim"}),(0,b.jsx)(r.Ss,{className:"tab-indicator ".concat(null!==j?"dragging":""),style:{left:"".concat(null===j?(y+.5)*C:j,"%")}}),x.map(function(n){var e=n.pagePath===g;return(0,b.jsxs)(r.Ss,{className:"tab-item ".concat(e?"active":""),children:[(0,b.jsx)(r._V,{className:"tab-icon-img ".concat(e?"active":""),src:e?n.iconActive:n.icon,mode:"aspectFit"}),(0,b.jsx)(r.EY,{className:"tab-label",children:n.label})]},n.pagePath)})]})]})}Component((0,a.createComponentConfig)(N,"custom-tab-bar/index"))}},function(n){var e=function(e){return n(n.s=e)};n.O(0,[907,96,76],function(){return e(7914)});n.O()}]);

src/custom-tab-bar/index.tsx

@@ -5,7 +5,7 @@ import { getTheme, resolveTheme, setDetectedSystemTheme } from '../utils/store'
 import { THEME_CHANGE_EVENT } from '../context/ThemeContext'
 import { applyPageBackground } from '../utils/themeBackground'
 import { assetUrl } from '../utils/asset'
-import { clampDragX, getTabBarFrame, tabIndexAtX } from './tabBarGeometry'
+import { clampPercent, getTabBarFrame, hasDragged, tabIndexAtPercent } from './tabBarGeometry'
 import './index.scss'
 
 const TABS = [
@@ -17,6 +17,7 @@ const TABS = [
 ]
 
 const TAB_CENTER_STEP = 100 / TABS.length
+const DRAG_THRESHOLD_PX = 12
 
 function matchTab(path: string): string {
   const idx = TABS.findIndex((t) => path.endsWith(t.pagePath))
@@ -39,8 +40,9 @@ export default function CustomTabBar() {
 
   // 微信自定义 tabBar 不会自动感知 page 路由变化，用 state 保持选中态响应式
   const [activeTab, setActiveTab] = useState<string>(currentTabPath)
-  const [dragX, setDragX] = useState<number | null>(null)
-  const dragXRef = useRef<number | null>(null)
+  const [dragPercent, setDragPercent] = useState<number | null>(null)
+  const dragPercentRef = useRef<number | null>(null)
+  const startXRef = useRef<number>(0)
   const barFrameRef = useRef<{ left: number; width: number } | null>(null)
 
   useEffect(() => {
@@ -102,38 +104,47 @@ export default function CustomTabBar() {
     if (!touch) return
     const frame = getTabBarFrame(Taro.getSystemInfoSync().windowWidth)
     barFrameRef.current = frame
-    const nextX = clampDragX(touch.clientX - frame.left, frame.width)
-    dragXRef.current = nextX
-    setDragX(nextX)
+    startXRef.current = touch.clientX
+    dragPercentRef.current = null
+    setDragPercent(null)
   }
 
   const moveDrag = (e: any) => {
-    if (dragXRef.current === null) return
     const frame = barFrameRef.current
     const touch = e.touches && e.touches[0]
     if (!frame || !touch) return
-    const nextX = clampDragX(touch.clientX - frame.left, frame.width)
-    dragXRef.current = nextX
-    setDragX(nextX)
+    if (dragPercentRef.current === null && !hasDragged(startXRef.current, touch.clientX, DRAG_THRESHOLD_PX)) {
+      return
+    }
+    const nextPercent = clampPercent(((touch.clientX - frame.left) / frame.width) * 100)
+    dragPercentRef.current = nextPercent
+    setDragPercent(nextPercent)
   }
 
-  const endDrag = () => {
+  const endDrag = (e: any) => {
     const frame = barFrameRef.current
-    const x = dragXRef.current
-    if (frame && x !== null) {
-      const idx = tabIndexAtX(x, frame.width, TABS.length)
-      const target = TABS[idx]
-      if (target && target.pagePath !== activeTab) switchTab(target.pagePath)
+    if (!frame) return
+    let targetIndex: number
+    if (dragPercentRef.current !== null) {
+      targetIndex = tabIndexAtPercent(dragPercentRef.current, TABS.length)
+    } else {
+      const touch = e.changedTouches && e.changedTouches[0]
+      const x = touch ? touch.clientX : startXRef.current
+      targetIndex = tabIndexAtPercent(clampPercent(((x - frame.left) / frame.width) * 100), TABS.length)
     }
+    const target = TABS[targetIndex]
+    if (target && target.pagePath !== activeTab) switchTab(target.pagePath)
     barFrameRef.current = null
-    dragXRef.current = null
-    setDragX(null)
+    startXRef.current = 0
+    dragPercentRef.current = null
+    setDragPercent(null)
   }
 
   const cancelDrag = () => {
     barFrameRef.current = null
-    dragXRef.current = null
-    setDragX(null)
+    startXRef.current = 0
+    dragPercentRef.current = null
+    setDragPercent(null)
   }
 
   const activeIndex = Math.max(0, TABS.findIndex((t) => t.pagePath === activeTab))
@@ -152,8 +163,8 @@ export default function CustomTabBar() {
         <View className='tab-bar-caustic' />
         <View className='tab-bar-rim' />
         <View
-          className={`tab-indicator ${dragX !== null ? 'dragging' : ''}`}
-          style={{ left: dragX === null ? `calc(${(activeIndex + 0.5) * TAB_CENTER_STEP}%)` : `${dragX}px` }}
+          className={`tab-indicator ${dragPercent !== null ? 'dragging' : ''}`}
+          style={{ left: dragPercent === null ? `${(activeIndex + 0.5) * TAB_CENTER_STEP}%` : `${dragPercent}%` }}
         />
         {TABS.map((tab) => {
           const isActive = tab.pagePath === activeTab

src/custom-tab-bar/tabBarGeometry.js

@@ -3,16 +3,17 @@ export function clamp(value, min, max) {
   return Math.min(max, Math.max(min, value))
 }
 
-export function clampDragX(x, barWidth) {
-  return clamp(x, 0, Math.max(0, barWidth))
+export function clampPercent(value) {
+  return clamp(value, 0, 100)
 }
 
-export function tabIndexAtX(x, barWidth, tabCount) {
-  if (!Number.isFinite(x) || !Number.isFinite(barWidth) || barWidth <= 0 || tabCount <= 0) {
-    return 0
-  }
-  const ratio = clampDragX(x, barWidth) / barWidth
-  return clamp(Math.floor(ratio * tabCount), 0, tabCount - 1)
+export function tabIndexAtPercent(percent, tabCount) {
+  if (!Number.isFinite(percent) || tabCount <= 0) return 0
+  return clamp(Math.floor((clampPercent(percent) / 100) * tabCount), 0, tabCount - 1)
+}
+
+export function hasDragged(startX, currentX, threshold) {
+  return Math.abs(currentX - startX) >= threshold
 }
 
 export function getTabBarFrame(windowWidth) {

tools/custom-tab-bar.test.mjs

@@ -1,21 +1,27 @@
 import test from 'node:test'
 import assert from 'node:assert/strict'
-import { clampDragX, getTabBarFrame, tabIndexAtX } from '../src/custom-tab-bar/tabBarGeometry.js'
+import { clampPercent, getTabBarFrame, hasDragged, tabIndexAtPercent } from '../src/custom-tab-bar/tabBarGeometry.js'
 
-test('maps a drag x to the tab under the finger', () => {
-  assert.equal(tabIndexAtX(10, 100, 5), 0)
-  assert.equal(tabIndexAtX(30, 100, 5), 1)
-  assert.equal(tabIndexAtX(50, 100, 5), 2)
-  assert.equal(tabIndexAtX(70, 100, 5), 3)
-  assert.equal(tabIndexAtX(90, 100, 5), 4)
+test('maps a drag percent to the tab under the finger', () => {
+  assert.equal(tabIndexAtPercent(10, 5), 0)
+  assert.equal(tabIndexAtPercent(30, 5), 1)
+  assert.equal(tabIndexAtPercent(50, 5), 2)
+  assert.equal(tabIndexAtPercent(70, 5), 3)
+  assert.equal(tabIndexAtPercent(90, 5), 4)
 })
 
-test('clamps drag positions outside the bar', () => {
-  assert.equal(tabIndexAtX(-10, 100, 5), 0)
-  assert.equal(tabIndexAtX(200, 100, 5), 4)
-  assert.equal(clampDragX(-5, 100), 0)
-  assert.equal(clampDragX(120, 100), 100)
-  assert.equal(clampDragX(Number.NaN, 100), 0)
+test('clamps percent and maps out-of-range to edge tabs', () => {
+  assert.equal(clampPercent(-5), 0)
+  assert.equal(clampPercent(120), 100)
+  assert.equal(clampPercent(Number.NaN), 0)
+  assert.equal(tabIndexAtPercent(-5, 5), 0)
+  assert.equal(tabIndexAtPercent(120, 5), 4)
+})
+
+test('only treats a move as a drag beyond the threshold', () => {
+  assert.equal(hasDragged(100, 110, 12), false)
+  assert.equal(hasDragged(100, 112, 12), true)
+  assert.equal(hasDragged(100, 88, 12), true)
 })
 
 test('derives the floating bar frame from window width', () => {