Question

我使用此代码检查我的iphone的audiojack中是否有插入或插入的东西

    void audioRouteChangeListenerCallback (void *inUserData, AudioSessionPropertyID inPropertyID, UInt32 inPropertyValueSize, const void *inPropertyValue ) {
        // ensure that this callback was invoked for a route change
        if (inPropertyID != kAudioSessionProperty_AudioRouteChange) return;

        {
            // Determines the reason for the route change, to ensure that it is not
            //      because of a category change.
            CFDictionaryRef routeChangeDictionary = (CFDictionaryRef)inPropertyValue;

            CFNumberRef routeChangeReasonRef = (CFNumberRef)CFDictionaryGetValue (routeChangeDictionary, CFSTR (kAudioSession_AudioRouteChangeKey_Reason) );
            SInt32 routeChangeReason;
            CFNumberGetValue (routeChangeReasonRef, kCFNumberSInt32Type, &routeChangeReason);

            if (routeChangeReason == kAudioSessionRouteChangeReason_OldDeviceUnavailable) {
                  //Handle Headset Unplugged
                NSLog(@"PluggedOut");


            }
            else if (routeChangeReason == kAudioSessionRouteChangeReason_NewDeviceAvailable)
            {
                //Handle Headset plugged in
                NSLog(@"Something Plugged In");
            }

}

但是当我添加我的目标C方法（在所有其他代码中都很完美）来确定插入的设备是否是我的读卡器时，它最终会出现EXC_BAD_ACCESS错误我试过的是下面的代码

else if (routeChangeReason == kAudioSessionRouteChangeReason_NewDeviceAvailable)
                    {
                        //Handle Headset plugged in
                        NSLog(@"Something Plugged In");
  audiotest *test;
            if([test Checkheadphonestatus] == 1)
            {
                NSLog(@"Your iPosReader Connected");
            }
            else if([test Checkheadphonestatus] == 0)
            {
                NSLog(@"Connected device was not iPos Reader");
            }
                    }

        }

任何建议都将受到赞赏。

Answer 1

audiotest *test;

您似乎尚未初始化test。尝试将其替换为：

audiotest *test = [[audiotest alloc] init];

另外作为旁注，它是PascalCase的一个Objective-C约定你的类名和camelCase你的方法名。例如：

AudioTest *test = [[AudioTest alloc] init];
int status = [test checkHeadphoneStatus];

在audioRouteChangeListenerCallback方法中调用目标C方法时出错

1 个答案: