ios 类似QQ登录成功后的提示框

效果如下：

- (void)showMessage:(NSString *)message
{
    UIWindow * window = [UIApplication sharedApplication].keyWindow;
    UIView *showview =  [[UIView alloc]init];
    showview.backgroundColor = [UIColor blackColor];
    showview.frame = CGRectMake(1, 1, 1, 1);
    showview.alpha = 1.0f;
    showview.layer.cornerRadius = 5.0f;
    showview.layer.masksToBounds = YES;
    showview.frame = CGRectMake((kDEVICEWIDTH - 90 )/2, (kDEVICEHEIGHT-90)/2.0 , 90, 90);
    [window addSubview:showview];
    
    UIImageView *_imageView = [[UIImageView alloc]init];
    [_imageView setFrame:CGRectMake((90 - 30)/2.0, 20, 30, 30)];
    _imageView.image = [UIImage imageNamed:@"toast_success"];
    [showview addSubview:_imageView];
    
    
    UILabel *label = [[UILabel alloc]init];
    CGSize LabelSize = [message sizeWithFont:[UIFont systemFontOfSize:17] constrainedToSize:CGSizeMake(290, 9000)];
    label.frame = CGRectMake(10, 60, LabelSize.width, LabelSize.height);
    label.text = message;
    label.textColor = [UIColor whiteColor];
    label.textAlignment = 1;
    label.backgroundColor = [UIColor clearColor];
    label.font = [UIFont boldSystemFontOfSize:15];
    [showview addSubview:label];
    
    [UIView animateWithDuration:2 animations:^{
        showview.alpha = 0;
    } completion:^(BOOL finished)
     {
         [showview removeFromSuperview];
         
         MyOrderViewController *_viewController = [[MyOrderViewController alloc] init];
         _viewController.backViewConTrollerType = @"ViewConTroller";
         [self.navigationController pushViewController:_viewController animated:YES];
     }];
}