nantai-erp-wechat-mobile/miniprogram_npm/vant-weapp/picker-column/index.js
2024-10-31 21:29:57 +08:00

135 lines
4.1 KiB
JavaScript

import { VantComponent } from '../common/component';
import { isObj, range } from '../common/utils';
const DEFAULT_DURATION = 200;
VantComponent({
classes: ['active-class'],
props: {
valueKey: String,
className: String,
itemHeight: Number,
visibleItemCount: Number,
initialOptions: {
type: Array,
value: []
},
defaultIndex: {
type: Number,
value: 0
}
},
data: {
startY: 0,
offset: 0,
duration: 0,
startOffset: 0,
options: [],
currentIndex: 0
},
created() {
const { defaultIndex, initialOptions } = this.data;
this.set({
currentIndex: defaultIndex,
options: initialOptions
}).then(() => {
this.setIndex(defaultIndex);
});
},
computed: {
count() {
return this.data.options.length;
},
baseOffset() {
const { data } = this;
return (data.itemHeight * (data.visibleItemCount - 1)) / 2;
},
wrapperStyle() {
const { data } = this;
return [
`transition: ${data.duration}ms`,
`transform: translate3d(0, ${data.offset + data.baseOffset}px, 0)`,
`line-height: ${data.itemHeight}px`
].join('; ');
}
},
watch: {
defaultIndex(value) {
this.setIndex(value);
}
},
methods: {
onTouchStart(event) {
this.set({
startY: event.touches[0].clientY,
startOffset: this.data.offset,
duration: 0
});
},
onTouchMove(event) {
const { data } = this;
const deltaY = event.touches[0].clientY - data.startY;
this.set({
offset: range(data.startOffset + deltaY, -(data.count * data.itemHeight), data.itemHeight)
});
},
onTouchEnd() {
const { data } = this;
if (data.offset !== data.startOffset) {
this.set({
duration: DEFAULT_DURATION
});
const index = range(Math.round(-data.offset / data.itemHeight), 0, data.count - 1);
this.setIndex(index, true);
}
},
onClickItem(event) {
const { index } = event.currentTarget.dataset;
this.setIndex(index, true);
},
adjustIndex(index) {
const { data } = this;
index = range(index, 0, data.count);
for (let i = index; i < data.count; i++) {
if (!this.isDisabled(data.options[i]))
return i;
}
for (let i = index - 1; i >= 0; i--) {
if (!this.isDisabled(data.options[i]))
return i;
}
},
isDisabled(option) {
return isObj(option) && option.disabled;
},
getOptionText(option) {
const { data } = this;
return isObj(option) && data.valueKey in option
? option[data.valueKey]
: option;
},
setIndex(index, userAction) {
const { data } = this;
index = this.adjustIndex(index) || 0;
const offset = -index * data.itemHeight;
if (index !== data.currentIndex) {
return this.set({ offset, currentIndex: index }).then(() => {
userAction && this.$emit('change', index);
});
}
return this.set({ offset });
},
setValue(value) {
const { options } = this.data;
for (let i = 0; i < options.length; i++) {
if (this.getOptionText(options[i]) === value) {
return this.setIndex(i);
}
}
return Promise.resolve();
},
getValue() {
const { data } = this;
return data.options[data.currentIndex];
}
}
});