可以監聽有電話來時候的一些狀態

#import <coretelephony ctcallcenter.h="">

import <coretelephony ctcall.h="">
-(void)detectCall

  {

       CTCallCenter callCenter = [[CTCallCenter alloc] init];

      callCenter.callEventHandler=^(CTCall call)

      {

          if (call.callState == CTCallStateDisconnected)

          {

              NSLog(@"Call has been disconnected");

      }  
      else if (call.callState == CTCallStateConnected)  
      {  
          NSLog(@"Call has just been connected");  
      }  

      else if(call.callState == CTCallStateIncoming)  
      {  
          NSLog(@"Call is incoming");  

      }  

      else if (call.callState ==CTCallStateDialing)  
      {  
          NSLog(@"call is dialing");  
      }  
      else
      {  
          NSLog(@"Nothing is done");  
      }  
  };  

}  </coretelephony></coretelephony></pre>