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1×
| <template>
<div class="mu-picker-slot" :class="{'mu-picker-slot-divider': divider}" :style="{'width': width}">
<div v-if="!divider" class="mu-picker-slot-wrapper" :class="{'animate': animate}" :style="{'height': contentHeight + 'px'}" ref="wrapper">
<div class="mu-picker-item" :style="{'text-align': textAlign}" :class="{'selected': item === value}"
v-for="item, index in values" :key="index">{{item.text || item}}</div>
</div>
<div v-if="divider">{{ content }}</div>
</div>
</template>
<script>
import Vue from 'vue'
import Drag from '../utils/drag'
import translateUtil from '../utils/translate'
import * as domUtil from '../utils/domUtil'
const ITEM_HEIGHT = 36
export default {
props: {
divider: {
type: Boolean,
default: false
},
content: {
type: String,
default: ''
},
values: {
type: Array,
default () {
return []
}
},
value: {},
textAlign: {
type: String,
default: ''
},
width: {
type: String,
default: ''
},
visibleItemCount: {
type: Number,
default: 5
}
},
data () {
return {
animate: false
}
},
computed: {
contentHeight () {
return ITEM_HEIGHT * this.visibleItemCount
},
valueIndex () {
return this.values.indexOf(this.value)
},
dragRange () {
let values = this.values
let visibleItemCount = this.visibleItemCount
return [ -ITEM_HEIGHT * (values.length - Math.ceil(visibleItemCount / 2)), ITEM_HEIGHT * Math.floor(visibleItemCount / 2) ]
}
},
mounted: function () {
if (!this.divider) {
this.initEvents()
this.doOnValueChange()
}
},
methods: {
value2Translate (value) {
let values = this.values
let valueIndex = values.indexOf(value)
let offset = Math.floor(this.visibleItemCount / 2)
if (valueIndex !== -1) {
return (valueIndex - offset) * -ITEM_HEIGHT
}
},
translate2Value (translate) {
translate = Math.round(translate / ITEM_HEIGHT) * ITEM_HEIGHT
let index = -(translate - Math.floor(this.visibleItemCount / 2) * ITEM_HEIGHT) / ITEM_HEIGHT
return this.values[index]
},
doOnValueChange () {
let value = this.value
let wrapper = this.$refs.wrapper
translateUtil.translateElement(wrapper, null, this.value2Translate(value))
},
doOnValuesChange () {
let el = this.$el
let items = el.querySelectorAll('.mu-picker-item')
Array.prototype.forEach.call(items, (item, index) => {
translateUtil.translateElement(item, null, ITEM_HEIGHT * index)
})
},
initEvents () {
let el = this.$refs.wrapper
let drag = new Drag(el)
let startTop = 0
let velocityTranslate, prevTranslate
drag.start(() => {
startTop = translateUtil.getElementTranslate(el).top
}).drag((endPos, event) => {
event.preventDefault()
event.stopPropagation()
let translate = startTop + endPos.y
translateUtil.translateElement(el, 0, translate)
velocityTranslate = translate - prevTranslate || translate
prevTranslate = translate
}).end((endPos) => {
const momentumRatio = 7
let currentTranslate = translateUtil.getElementTranslate(el).top
let momentumTranslate
if (endPos.time < 300) {
momentumTranslate = currentTranslate + velocityTranslate * momentumRatio
}
let dragRange = this.dragRange
this.animate = true
domUtil.transitionEnd(el, () => {
this.animate = false
})
Vue.nextTick(() => {
let translate
if (momentumTranslate) {
translate = Math.round(momentumTranslate / ITEM_HEIGHT) * ITEM_HEIGHT
} else {
translate = Math.round(currentTranslate / ITEM_HEIGHT) * ITEM_HEIGHT
}
translate = Math.max(Math.min(translate, dragRange[1]), dragRange[0])
translateUtil.translateElement(el, null, translate)
this.$emit('change', this.translate2Value(translate))
})
})
}
},
watch: {
values (newVal) {
if (this.valueIndex === -1) {
this.value = (newVal || [])[0]
}
},
value () {
this.doOnValueChange()
}
}
}
</script>
<style lang="less">
@import "../styles/import.less";
.mu-picker-slot{
.flex-shrink(1);
font-size: 18px;
overflow: hidden;
position: relative;
max-height: 100%;
text-align: center;
&.mu-picker-slot-divider{
color: @textColor;
display: flex;
align-items: center;
line-height: 36px;
}
}
.mu-picker-slot-wrapper.animate{
transition: transform .45s @easeOutFunction;
backface-visibility: hidden;
}
.mu-picker-item{
line-height: 36px;
padding: 0 10px;
font-size: 20px;
white-space: nowrap;
position: relative;
overflow: hidden;
text-overflow: ellipsis;
color: @secondaryTextColor;
left: 0;
top: 0;
width: 100%;
box-sizing: border-box;
transition-duration: .3s;
backface-visibility: hidden;
&.selected {
color: @textColor;
transform: translate3d(0, 0, 0) rotateX(0);
}
}
</style>
|