百度智能小程序 开始监听罗盘数据

swan.startCompass

解释：开始监听罗盘数据。

Web 态说明：由于浏览器对于 W3C 规范的实现差异，startCompass 功能在部分浏览器(比如 Safari 浏览器)下不可用，在功能不可用情况下会执行开发者设置的 fail 回调。

方法参数

Object object

object 参数说明

示例 

在开发者工具中打开

图片示例

代码示例

<view class="card-area">
    <view class="wrap">
        <view class="page-top">
            <view class="tip-week">{{title}}</view>
        </view>
        <view class="direction">
            <view class="bg-compass-line"></view>
            <view class="bg-compass" style="transform: rotate(-{{direction}}deg)">
                <view class="num num0" style="transform: rotate({{direction}}deg)">0</view>
                <view class="num num90" style="transform: rotate({{direction}}deg)">90</view>
                <view class="num num180" style="transform: rotate({{direction}}deg)">180</view>
                <view class="num num270" style="transform: rotate({{direction}}deg)">270</view>
            </view>
            <div class="cg-wrap">
                <div class="circle-left-wrap"><div class="circle-left" style="transform:rotate({{leftdeg}}deg);transform-origin:50% 50%"></div></div>
                <div class="circle-right-wrap"><div class="circle-right" style="transform:rotate({{rightdeg}}deg);transform-origin:50% 50%"></div></div>
                <div class="mask">
                    <view class="direction-num">
                        <text>{{direction}}</text>
                        <text class="direction-degree"></text>
                    </view>
                </div>
            </div>
        </view>
        <view class="page-body-btn">
            <view class="middle-btn {{!isWatch ? '' : 'disabled'}}" bind:tap="startWatch">开始监听</view>
            <view class="middle-btn {{!isWatch ? 'disabled' : ''}}" bind:tap="stopWatch">停止监听</view >
        </view>
    </view>
</view>

Page({
    data: {
        title: '旋转手机即可获取方位信息',
        direction: 0,
        isWatch: true,
        leftdeg: 0,
        rightdeg: 0
    },

    onReady() {
        swan.onCompassChange(res => {
            this.setData({
                direction: parseInt(res.direction, 10)
            });
            this.updateProgress(res.direction);
        });
    },
    onShow() {
        let isWatch = this.data.isWatch;
        isWatch ? swan.startCompass() : swan.stopCompass();
    },
    startWatch() {
        this.setData('isWatch', true);
        swan.startCompass();
    },
    stopWatch() {
        this.setData('isWatch', false);
        swan.stopCompass();
    },
    updateProgress(direction) {
        let leftdeg;
        let rightdeg;
        let deg = +direction;
        if (deg > 180) {
            leftdeg = 180;
            rightdeg = 180 - deg;
        }
        else {
            leftdeg = -deg;
            rightdeg = 0;
        }
        this.setData({
            leftdeg,
            rightdeg
        });
    }
});