高德地图设置默认位置和级别，注意设置级别要在设置小蓝点之前，若在之后会变成北京。
[AMapServices sharedServices].enableHTTPS = YES;
///初始化地图
_mapView = [[MAMapView alloc] initWithFrame:self.view.bounds];
///把地图添加至view
[self.view addSubview:_mapView];
[_mapView setZoomLevel:16.1 animated:YES];
///如果您需要进入地图就显示定位小蓝点，则需要下面两行代码
_mapView.showsUserLocation = YES;
_mapView.userTrackingMode = MAUserTrackingModeFollow;
