我正在关注这本书,iOS编程大书呆子牧场指南,我已经上了一堂课,我要创建一个自定义视图,HypnosisView.现在,我想这个观点会改变它的摇晃颜色,但它说我想让它成为第一反应者.
我用了,
- (BOOL)canBecomeFirstResponder
{
return YES;
}
和
BOOL success = [view becomeFirstResponder];
if (success) {
NSLog(@"HypnosisView became the first responder"):
} else {
NSLog(@"Could not become first responder");
}
但是,每当我运行我的应用程序时,它总是说它不能成为第一个响应者.
任何帮助,将不胜感激.
UPDATE
我忘了提到我得到这个输出消息.
Application windows are expected to have a root view controller at the end of application launch