iOS 动画效果弹出提示视图

//弹出提示框,增加了动画效果,当animationDirection参数为nil的时候,默认动画方向是从下至上弹出,如果要改变弹出方向,只要改变animationDirection即可

-(void)showAlertContentViewOnKeyWindow:(UIView*)alertView animationDirection:(NSString
*)animationDirection{

    UIWindow *keyWindow = [UIApplication sharedApplication].keyWindow;

    
   CGRect bounds =
CGRectMake(0,0,
WIDTH, HEIGHT);
   self.grayView = [[UIView alloc]
initWithFrame:bounds];
    [keyWindow addSubview:self.grayView];

    
    UIView *converView = [[UIView alloc]
initWithFrame:bounds];
    converView.backgroundColor = [UIColor blackColor];
    converView.alpha =0.4;
    [self.grayView addSubview:converView];

    

   
//用于设置弹出视图的动画效果

    CATransition *animation = [CATransition animation];
    animation.duration =0.3;

    animation.timingFunction =UIViewAnimationCurveEaseInOut;

    animation.fillMode =kCAFillModeForwards;

    animation.type =kCATransitionPush;//还有这几种动画：kCATransitionPush，kCATransitionReveal，kCATransitionFade
   if (animationDirection==nil) {

        animation.subtype =kCATransitionFromTop;//移动方向：从下至上
    }elseif ([animationDirection
isEqualToString:@"RIGHT"]){
        animation.type =kCATransitionFade;

        animation.subtype =kCATransitionFromRight;//移动方向：从右至左
    }
    [alertView.layeraddAnimation:animation
forKey:@"animation"];
    [self.grayView addSubview:alertView]; 
}