iOS-自定义alertView(非常实用)

@interface AlertModel()
{
    UIView * _popTopView;
    UIView * _maskView;

}
@end
@implementation AlertModel
#pragma mark -- 懒加载
- (UIView *)popTopView {
    if (!_popTopView) {
        // 自定义弹框内容
        _popTopView = [[UIView alloc] initWithFrame:CGRectMake(10,  200, SCREEN_WIDTH-20, 300)];
        _popTopView.backgroundColor = [UIColor whiteColor];
        
        // 自定义弹框内容
        UIView *titleView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, SCREEN_WIDTH, 64.0f)];
        titleView.backgroundColor = [UIColor lightGrayColor];
        [_popTopView addSubview:titleView];
        
        UILabel *topTitleLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 20, SCREEN_WIDTH, 44.0f)];
        topTitleLabel.font = [UIFont systemFontOfSize:20.0];
        topTitleLabel.textAlignment = NSTextAlignmentCenter;
        topTitleLabel.textColor = [UIColor whiteColor];
        topTitleLabel.backgroundColor = [UIColor clearColor];
        topTitleLabel.text = @"切换工作室";
        [titleView addSubview:topTitleLabel];
        
        
    }
    return _popTopView;
}
- (UIView *)maskView {
    if (!_maskView) {
        _maskView = [[UIView alloc] initWithFrame:[UIScreen mainScreen].bounds];
        _maskView.backgroundColor = [UIColor colorWithWhite:0.000 alpha:0.400];
        _maskView.alpha = 0.0f;
        
        // 添加点击背景按钮
        UIButton *btn = [[UIButton alloc] initWithFrame:[UIScreen mainScreen].bounds];
        [btn addTarget:self action:@selector(close) forControlEvents:UIControlEventTouchUpInside];
        [_maskView addSubview:btn];
    }
    return _maskView;
}
- (void)openPopTopViewAction{ // 打开下拉弹框
    [[UIApplication sharedApplication].keyWindow addSubview:self.maskView];
    [[UIApplication sharedApplication].keyWindow addSubview:self.popTopView];
    
    [UIView animateWithDuration:0.25 animations:^{
        self.maskView.alpha = 1.0;
        //self.popTopView.transform = CGAffineTransformTranslate(self.popTopView.transform, 0, SCREEN_HEIGHT_NO_STATUS/ 2.0f);
        
    } completion:^(BOOL finished) {
        NSLog(@"%s", __func__);
    }];
}
- (void)close {
    // 关闭顶部视图动画
    [UIView animateWithDuration:0.3 animations:^{
        self.maskView.alpha = 0.0;
        self.popTopView.transform = CGAffineTransformIdentity;
    }completion:^(BOOL finished) {
        [self.maskView removeFromSuperview];
        [self.popTopView removeFromSuperview];
    }];
}
@end