开机动画 渐渐变大的效果

// 设置开机启动页面的动画效果

    UIImageView *niceView = [[UIImageView alloc] initWithFrame:CGRectMake(0,0, 375, 667)];

    niceView.image = [UIImage imageNamed:@"Default.png"];

    [UIApplication sharedApplication].statusBarHidden = YES;

    //添加到场景

    [self.window addSubview:niceView];

    //放到最顶层;

    [self.window bringSubviewToFront:niceView];

    //开始设置动画;

    [UIView animateWithDuration:2.0 animations:^{

        CGAffineTransform newTransform = CGAffineTransformMakeScale(1.2, 1.2);

        [niceView setTransform:newTransform];

    }completion:^(BOOL finished){

        [UIView animateWithDuration:1.2 animations:^{

            [niceView setAlpha:0];

        } completion:^(BOOL finished){

            [niceView removeFromSuperview];

            [UIApplication sharedApplication].statusBarHidden = NO;

        }];

    }];