-(void)motionEnded:(UIEventSubtype)motion withEvent:(UIEvent *)event{
    if(motion==UIEventSubtypeMotionShake)
    {
        代码A
    }
}
-(BOOL)canBecomeFirstResponder{
    return YES;
}
-(void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:animated];
    [self becomeFirstResponder];
}
-(void)viewWillDisappear:(BOOL)animated
{
    [self resignFirstResponder];
    [super viewWillDisappear:animated];
}第一次摇动的时候有相应,会执行到代码A;但是再摇就不管用了,请问为什么?