接电话，打电话等电话状态的检测：TelephoyCheck

1、导入CoreTelephony.framework

2、引入两个头文件

1. import <CoreTelephony/CTCallCenter.h>  2. import <CoreTelephony/CTCall.h>

3、定义变量(警告，最好不要在viewDidLoad中定义局部变量，最好是这种全局变量，否则因为变量被释放等无法接收来电话等的消息)

    _callCenter = [[CTCallCenter alloc] init];        _callCenter.callEventHandler = ^(CTCall call) {          if ([call.callState isEqualToString:CTCallStateDisconnected])          {              NSLog(@"挂断了电话咯 Call has been disconnected");            }          else if ([call.callState isEqualToString:CTCallStateConnected])          {              NSLog(@"电话通了 Call has just been connected");          }          else if([call.callState isEqualToString:CTCallStateIncoming])          {              NSLog(@"来电话了 Call is incoming");              // 用来做暂停录音之类的。          }          else if ([call.callState isEqualToString:CTCallStateDialing])          {              NSLog(@" 正在播出电话 call is dialing");          }          else          {              NSLog(@"嘛都没做 Nothing is done");          }      };</pre>
  
备注，接电话打印的流程： 
  
1.Call is incoming   2. Call has just been connected   3.Call has been disconnected
 
打电话的流程： 
  
1.call is dialing   2.Call has just been connected   3.Call has been disconnected
 
这个播出电话的测试我在其他项目测试过，不过这里到后台好像就被挂起了，因为也没什么定位之类的让他多存留一会，然后我在app delegate中的applicationDidEnterBackground里加了一段代码，保证了能测试出来。 
  
项目主页：http://www.open-open.com/lib/view/home/1449998312689