以下问题:我实现了一个Ping对象:@interfacePingTest:NSObject@property(strong,nonatomic)SimplePing*ping;我从Apple获得的SimplePing:https://developer.apple.com/library/mac/samplecode/SimplePing/Introduction/Intro.html现在我正尝试发送这样的Ping:@synthesizeping;ping=[SimplePingsimplePingWithHostName:PING_SERVER];ping.delegate=self