接電話，打電話等電話狀態的檢測：TelephoyCheck

1、導入CoreTelephony.framework

2、引入兩個頭文件

1. import <CoreTelephony/CTCallCenter.h>


import <CoreTelephony/CTCall.h></pre> 
3、定義變量(警告，最好不要在viewDidLoad中定義局部變量，最好是這種全局變量，否則因為變量被釋放等無法接收來電話等的消息) 
<h2>@property(strong,nonatomic) CTCallCenter *callCenter; </h2>
4、創建并接收回調等 
    _callCenter = [[CTCallCenter alloc] init];

_callCenter.callEventHandler = ^(CTCall* call) {

 if ([call.callState isEqualToString:CTCallStateDisconnected])
 {
     NSLog(@"掛斷了電話咯 Call has been disconnected");

 }
 else if ([call.callState isEqualToString:CTCallStateConnected])
 {
     NSLog(@"電話通了 Call has just been connected");
 }
 else if([call.callState isEqualToString:CTCallStateIncoming])
 {
     NSLog(@"來電話了 Call is incoming");
     // 用來做暫停錄音之類的。
 }
 else if ([call.callState isEqualToString:CTCallStateDialing])
 {
     NSLog(@" 正在播出電話 call is dialing");
 }
 else
 {
     NSLog(@"嘛都沒做 Nothing is done");
 }

};</pre>

備注，接電話打印的流程： 
1.Call is incoming


Call has just been connected
3.Call has been disconnected</pre> 
打電話的流程： 
1.call is dialing
2.Call has just been connected
3.Call has been disconnected
 
這個播出電話的測試我在其他項目測試過，不過這里到后臺好像就被掛起了，因為也沒什么定位之類的讓他多存留一會，然后我在app delegate中的applicationDidEnterBackground里加了一段代碼，保證了能測試出來。 
項目主頁：http://www.baiduhome.net/lib/view/home/1449998312689