replace a UIview animation by a timer animation
问题 well here is my code : - (CGPoint)randomPointSquare { CGRect frame = [[self view] frame]; //CGFloat rand_x = ((float)arc4random() / (float)UINT_MAX) * (float)_window.frame.size.width; NSInteger side = arc4random() / (UINT_MAX/4); CGFloat offset = 0; switch(side) { case 0: /* top */ offset = ((float)arc4random() / (float)UINT_MAX) * (float)frame.size.width; return CGPointMake(offset, -10); case 1: /* bottom */ offset = ((float)arc4random() / (float)UINT_MAX) * (float)frame.size.width; return