all files / picker/ picker-slot.vue

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
 
 
 
 
 
 
 
 
 
 
 
1×
1×
1×
1×
1×
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
//
//
//
//
//
//
//
//
//
//
 
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()
    }
  }
}