MKMapView画线，看了一位同学的笔记，感觉对大家有用，传上来共享一下，与大家共同进步-MKMapView Line

ent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition t