我有崩溃信息:*Terminatingappduetouncaughtexception'NSInvalidArgumentException',reason:'SettingfocusPointOfInterestisnotsupportedbythisdevice.UseisFocusPointOfInterestSupported'代码后:-(void)touchesBegan:(NSSet*)toucheswithEvent:(UIEvent*)event{[devicesetFocusPointOfInterest:CGPointMake(100,100)];}有没有办法像相