IOS开发：监听来电状态的改变。

#import <CoreTelephony/CTCallCenter.h>

#import <CoreTelephony/CTCall.h>

@property(nonatomic,strong)CTCallCenter *callCenter;

以下代码写在didFinishLaunchingWithOptions中。

必须将callCenter声明为成员变量，否则无法监听。

self.callCenter = [[CTCallCenter alloc] init];

self.callCenter.callEventHandler = ^(CTCall* call) {

if ([call.callState isEqualToString:CTCallStateDisconnected])

{

NSLog(@"Call has been disconnected");

}

else if ([call.callState isEqualToString:CTCallStateConnected])

{

NSLog(@"Call has just been connected");

}

else if([call.callState isEqualToString:CTCallStateIncoming])

{

NSLog(@"Call is incoming");

}

else if ([call.callState isEqualToString:CTCallStateDialing])

{

NSLog(@"call is dialing");

}

else

{

NSLog(@"Nothing is done");

}

};