picker增加滚动效果, 和点击选择, layer优化~

src/components/picker/picker-slot.vue

@@ -1,7 +1,7 @@
 <template>
   <div class="weui-picker__group" v-if="!divider">
     <div class="weui-picker__mask"></div>
-    <div class="weui-picker__indicator"></div>
+    <div class="weui-picker__indicator" ref="indicator"></div>
     <div class="weui-picker__content" ref="listWrapper">
       <div class="weui-picker__item" :class="{ 'weui-picker__item_disabled': typeof item === 'object' && item['disabled'] }" v-for="(item, key, index) in mutatingValues" :key="key">{{ typeof item === 'object' && item[valueKey] ? item[valueKey] : item }}</div>
     </div>
@@ -66,7 +66,16 @@
       },
 
       valueIndex () {
-        return this.mutatingValues.indexOf(this.currentValue)
+        var valueKey = this.valueKey
+        if(this.currentValue instanceof Object){
+          //写个顺序查找好了
+          for(var i = 0, len = this.mutatingValues.length; i < len ; i++){
+            if(this.currentValue[valueKey] === this.mutatingValues[i][valueKey])
+              return i
+          }
+          return -1
+        }else
+          return this.mutatingValues.indexOf(this.currentValue)
       }
     },
 
@@ -78,51 +87,58 @@
       if (this.divider) return
 
       const wrapper = this.$refs.listWrapper
+      const indicator = this.$refs.indicator
       Transform(wrapper, true)
 
       this.doOnValueChange()
 
       draggable(this.$el, {
         start: (event) => {
-          this.isDragging = true
           let dragState = this.dragState
 
           dragState.start = new Date()
           dragState.startPositionY = event.clientY
           dragState.startTranslateY = wrapper.translateY
+
+          wrapper.style.transition = null
         },
         drag: (event) => {
           let dragState = this.dragState
           const deltaY = event.clientY - dragState.startPositionY
 
-          const tempTranslateY = dragState.startTranslateY + deltaY
-
-          if (tempTranslateY <= this.minTranslateY) {
-            wrapper.translateY = this.minTranslateY
-          } else if (tempTranslateY >= this.maxTranslateY) {
-            wrapper.translateY = this.maxTranslateY
-          } else {
-            wrapper.translateY = dragState.startTranslateY + deltaY
-          }
-
+          wrapper.translateY = dragState.startTranslateY + deltaY
           dragState.currentPosifionY = event.clientY
           dragState.currentTranslateY = wrapper.translateY
-          dragState.velocityTranslate = dragState.currentTranslateY - dragState.prevTranslateY
-
+          dragState.velocityTranslate = 
+            dragState.currentTranslateY - dragState.prevTranslateY
           dragState.prevTranslateY = dragState.currentTranslateY
         },
-        end: () => {
-          this.isDragging = false
-
+        end: (event) => {
           let dragState = this.dragState
           let momentumRatio = 7
           let currentTranslate = wrapper.translateY
           let duration = new Date() - dragState.start
+          let distance = Math.abs(dragState.startTranslateY - currentTranslate)
+
+          let rect, offset
+          if(distance < 6){
+            rect = indicator.getBoundingClientRect()
+            offset = Math.floor((event.clientY - rect.top)/ITEM_HEIGHT) * ITEM_HEIGHT
+
+            if(offset > this.maxTranslateY )
+              offset = this.maxTranslateY
+
+            dragState.velocityTranslate = 0
+            currentTranslate -= offset
+          }
 
           let momentumTranslate
           if (duration < 300) {
             momentumTranslate = currentTranslate + dragState.velocityTranslate * momentumRatio
           }
+
+
+          wrapper.style.transition = 'all 200ms ease'
 
           this.$nextTick(() => {
             let translate
@@ -144,8 +160,7 @@
 
     methods: {
       value2translate (value) {
-        const values = this.mutatingValues
-        const valueIndex = values.indexOf(value)
+        const valueIndex = this.valueIndex
         const offset = Math.floor(VISIBLE_ITEM_COUNT / 2)
 
         if (valueIndex !== -1) {
@@ -167,6 +182,41 @@
         if (this.divider) return
 
         wrapper.translateY = this.value2translate(value)
+      },
+
+      nearby (val, values){
+        var minOffset, minIndex, offset
+
+        if(Array.isArray(values) === false) 
+          return undefined
+
+        minIndex = 0
+        if(typeof val === 'number'){
+          minOffset = Math.abs(values[0] - val)
+
+          values.forEach((value, i)=>{
+            offset = Math.abs(value - val)
+            if(offset < minOffset){
+              minIndex = i
+              minOffset = offset
+            }
+          })
+          return values[minIndex]
+        }else if(val instanceof Object){
+          if(typeof val.value === 'number'){
+            minOffset = Math.abs(values[0].value - val.value)
+
+            values.forEach((value, i)=>{
+              offset = Math.abs(value.value - val.value)
+              if(offset < minOffset){
+                minIndex = i
+                minOffset = offset
+              }
+            })
+            return values[minIndex]
+          }
+        }
+        return values[0]
       }
     },
 
@@ -177,7 +227,7 @@
 
       mutatingValues (val) {
         if (this.valueIndex === -1) {
-          this.currentValue = (val || [])[0]
+          this.currentValue = this.nearby(this.currentValue, val)
         }
       },
 
@@ -191,6 +241,21 @@
 </script>
 
 <style scoped lang="scss">
+  .weui-picker__group{
+    z-index: 0;
+    overflow: hidden;
+  }
+  .weui-picker__mask{
+    z-index: 2;
+    height: 238px;
+  }
+  .weui-picker__indicator{
+    z-index: 3;
+  }
+  .weui-picker__content{
+    z-index: 1;
+  }
+
   .wv-picker-slot-divider {
     transform:translateY(106px);
   }

src/components/picker/picker.vue

@@ -112,11 +112,13 @@
         return null
       },
 
-      setSlotValue (index, value) {
+      setSlotValue (index, value, taskQueue) {
         this.$nextTick(() => {
           let slot = this.getSlot(index)
           if (slot) {
             slot.currentValue = value
+            if(taskQueue && taskQueue.length > 0)
+              slot.$nextTick(taskQueue.shift())
           }
         })
       },
@@ -132,8 +134,15 @@
       setSlotValues (index, values) {
         this.$nextTick(() => {
           let slot = this.getSlot(index)
+          var oldVal
           if (slot) {
+            oldVal = slot.currentValue
             slot.mutatingValues = values
+            slot.$nextTick(()=>{
+              if(oldVal !== undefined && oldVal !== null)
+                slot.doOnValueChange(oldVal)
+              oldVal = null
+            })
           }
         })
       },
@@ -148,9 +157,14 @@
           throw new Error('values length is not equal slot count.')
         }
 
+        var taskQueue = []
         values.forEach((value, index) => {
-          this.setSlotValue(index, value)
+          if(index !== 0)
+            taskQueue.push(()=>{
+              this.setSlotValue(index, value, taskQueue)
+            })
         })
+        this.setSlotValue(0, values[0], taskQueue)
       },
 
       cancel () {