quanyawei
2023-10-20 d8b41fff43a2cee6a8f714ffa807623b15803786
uni_modules/uview-ui/components/u-count-to/u-count-to.vue
New file
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<template>
   <text
      class="u-count-num"
      :style="{
         fontSize: $u.addUnit(fontSize),
         fontWeight: bold ? 'bold' : 'normal',
         color: color
      }"
   >{{ displayValue }}</text>
</template>
<script>
   import props from './props.js';
/**
 * countTo 数字滚动
 * @description 该组件一般用于需要滚动数字到某一个值的场景,目标要求是一个递增的值。
 * @tutorial https://www.uviewui.com/components/countTo.html
 * @property {String | Number}   startVal   开始的数值,默认从0增长到某一个数(默认 0 )
 * @property {String | Number}   endVal      要滚动的目标数值,必须 (默认 0 )
 * @property {String | Number}   duration   滚动到目标数值的动画持续时间,单位为毫秒(ms) (默认 2000 )
 * @property {Boolean}         autoplay   设置数值后是否自动开始滚动 (默认 true )
 * @property {String | Number}   decimals   要显示的小数位数,见官网说明(默认 0 )
 * @property {Boolean}         useEasing   滚动结束时,是否缓动结尾,见官网说明(默认 true )
 * @property {String}         decimal      十进制分割 ( 默认 "." )
 * @property {String}         color      字体颜色( 默认 '#606266' )
 * @property {String | Number}   fontSize   字体大小,单位px( 默认 22 )
 * @property {Boolean}         bold      字体是否加粗(默认 false )
 * @property {String}         separator   千位分隔符,见官网说明
 * @event {Function} end 数值滚动到目标值时触发
 * @example <u-count-to ref="uCountTo" :end-val="endVal" :autoplay="autoplay"></u-count-to>
 */
export default {
   name: 'u-count-to',
   data() {
      return {
         localStartVal: this.startVal,
         displayValue: this.formatNumber(this.startVal),
         printVal: null,
         paused: false, // 是否暂停
         localDuration: Number(this.duration),
         startTime: null, // 开始的时间
         timestamp: null, // 时间戳
         remaining: null, // 停留的时间
         rAF: null,
         lastTime: 0 // 上一次的时间
      };
   },
   mixins: [uni.$u.mpMixin, uni.$u.mixin,props],
   computed: {
      countDown() {
         return this.startVal > this.endVal;
      }
   },
   watch: {
      startVal() {
         this.autoplay && this.start();
      },
      endVal() {
         this.autoplay && this.start();
      }
   },
   mounted() {
      this.autoplay && this.start();
   },
   methods: {
      easingFn(t, b, c, d) {
         return (c * (-Math.pow(2, (-10 * t) / d) + 1) * 1024) / 1023 + b;
      },
      requestAnimationFrame(callback) {
         const currTime = new Date().getTime();
         // 为了使setTimteout的尽可能的接近每秒60帧的效果
         const timeToCall = Math.max(0, 16 - (currTime - this.lastTime));
         const id = setTimeout(() => {
            callback(currTime + timeToCall);
         }, timeToCall);
         this.lastTime = currTime + timeToCall;
         return id;
      },
      cancelAnimationFrame(id) {
         clearTimeout(id);
      },
      // 开始滚动数字
      start() {
         this.localStartVal = this.startVal;
         this.startTime = null;
         this.localDuration = this.duration;
         this.paused = false;
         this.rAF = this.requestAnimationFrame(this.count);
      },
      // 暂定状态,重新再开始滚动;或者滚动状态下,暂停
      reStart() {
         if (this.paused) {
            this.resume();
            this.paused = false;
         } else {
            this.stop();
            this.paused = true;
         }
      },
      // 暂停
      stop() {
         this.cancelAnimationFrame(this.rAF);
      },
      // 重新开始(暂停的情况下)
      resume() {
         if (!this.remaining) return
         this.startTime = 0;
         this.localDuration = this.remaining;
         this.localStartVal = this.printVal;
         this.requestAnimationFrame(this.count);
      },
      // 重置
      reset() {
         this.startTime = null;
         this.cancelAnimationFrame(this.rAF);
         this.displayValue = this.formatNumber(this.startVal);
      },
      count(timestamp) {
         if (!this.startTime) this.startTime = timestamp;
         this.timestamp = timestamp;
         const progress = timestamp - this.startTime;
         this.remaining = this.localDuration - progress;
         if (this.useEasing) {
            if (this.countDown) {
               this.printVal = this.localStartVal - this.easingFn(progress, 0, this.localStartVal - this.endVal, this.localDuration);
            } else {
               this.printVal = this.easingFn(progress, this.localStartVal, this.endVal - this.localStartVal, this.localDuration);
            }
         } else {
            if (this.countDown) {
               this.printVal = this.localStartVal - (this.localStartVal - this.endVal) * (progress / this.localDuration);
            } else {
               this.printVal = this.localStartVal + (this.endVal - this.localStartVal) * (progress / this.localDuration);
            }
         }
         if (this.countDown) {
            this.printVal = this.printVal < this.endVal ? this.endVal : this.printVal;
         } else {
            this.printVal = this.printVal > this.endVal ? this.endVal : this.printVal;
         }
         this.displayValue = this.formatNumber(this.printVal) || 0;
         if (progress < this.localDuration) {
            this.rAF = this.requestAnimationFrame(this.count);
         } else {
            this.$emit('end');
         }
      },
      // 判断是否数字
      isNumber(val) {
         return !isNaN(parseFloat(val));
      },
      formatNumber(num) {
         // 将num转为Number类型,因为其值可能为字符串数值,调用toFixed会报错
         num = Number(num);
         num = num.toFixed(Number(this.decimals));
         num += '';
         const x = num.split('.');
         let x1 = x[0];
         const x2 = x.length > 1 ? this.decimal + x[1] : '';
         const rgx = /(\d+)(\d{3})/;
         if (this.separator && !this.isNumber(this.separator)) {
            while (rgx.test(x1)) {
               x1 = x1.replace(rgx, '$1' + this.separator + '$2');
            }
         }
         return x1 + x2;
      },
      destroyed() {
         this.cancelAnimationFrame(this.rAF);
      }
   }
};
</script>
<style lang="scss" scoped>
@import "../../libs/css/components.scss";
.u-count-num {
   /* #ifndef APP-NVUE */
   display: inline-flex;
   /* #endif */
   text-align: center;
}
</style>