地图callout在ios上不显示，android手机显示正常，求解？

var obj = {
    id: i,
    width: 10,
    height: 10,
    iconPath: '../../images/marker.png',
    latitude: tli.location.lat,
    longitude: tli.location.lng,
    callout:{
      content:i+1,
      display: 'ALWAYS',
      fontSize: 12,
      color: '#ff9900',
      
    }