#pragma mark- 初始化 ：原点+高
- (instancetype)initWithOrigin:(CGPoint)origin andHeight:(CGFloat)height andDataArray:(NSMutableArray *)data;
{
    // 位置信息
    _origin = origin;
    _show=NO;
    _height = height;
    
    // 填充数据
    dataArray=data;
    numOfMenu=[dataArray count];
    currentSelectedMenudIndex=-1;
    
        // 绘制栏目头的轮廓
        self=[self initWithFrame:CGRectMake(origin.x, origin.y, ScreenSize.size.width,height)];
        // 每个button的宽度
        CGFloat buttonInertval=self.frame.size.width/numOfMenu;
        // 根据列数创建button
        [self createButton:buttonInertval andHeight:height];
        // 创建tableview
        [self createTableView:origin];
        // 创建背景+添加弹回事件
        [self createBackgroud:origin];
        // 给menu添加底边
        [self createShadow];
    
    self.backgroundColor=[UIColor whiteColor];
    return self;
}

绘制button

- (void)animateTableViewShow:(BOOL)show complete:(void(^)())complete {
    if(show)
    {
        // 左边占了七分天下
        _leftTableView.frame = CGRectMake(self.origin.x, self.frame.origin.y+_height, ScreenSize.size.width*0.7, 0);
        [self.superview addSubview:_leftTableView];
        
        // 右边有三分
        _rightTableView.frame = CGRectMake(self.origin.x+ScreenSize.size.width*0.7, self.frame.origin.y+_height,ScreenSize.size.width*0.3, 0);
        [self.superview addSubview:_rightTableView];
        _leftTableView.alpha = 1.f;
        _rightTableView.alpha = 1.f;
        [UIView animateWithDuration:0.2 animations:^{
            _leftTableView.frame = CGRectMake(self.origin.x, self.frame.origin.y+_height, ScreenSize.size.width*0.7, ScreenSize.size.height/3);
            _rightTableView.frame = CGRectMake(self.origin.x+ScreenSize.size.width*0.7, self.frame.origin.y+_height, ScreenSize.size.width*0.3, ScreenSize.size.height/3);
        } completion:^(BOOL finished) {
        }];
    }else
    {
        [UIView animateWithDuration:0.2 animations:^{
                        _leftTableView.alpha = 0.f;
                        _rightTableView.alpha = 0.f;
                    } completion:^(BOOL finished) {
                        [_leftTableView removeFromSuperview];
                        [_rightTableView removeFromSuperview];
                    }];
        
    }complete();

}

-(void)btnPressed:(id)sender
{
    UIButton *a=sender;
    currentSelectedMenudIndex=a.tag;
    CurrentArray=[[[dataArray objectAtIndex:currentSelectedMenudIndex-1] objectAtIndex:2] objectAtIndex:0];

    if (_show==0) {
        // 关闭所有
        for (NSInteger i=1; i<=numOfMenu;i++) {
            UIButton *tmpbutton=(UIButton*)[self viewWithTag:i];
            tmpbutton.imageView.transform=CGAffineTransformMakeRotation(0);
        }
        // 旋转图片
        a.imageView.transform=CGAffineTransformMakeRotation(M_PI);
        
        // Selects a row in the receiver identified by index path, optionally scrolling the row to a location in the receiver.
        // 以索引路径为标志选中接受者中的一行，可以选择滚动这一行到接受者的一个位置
        
        // animated :YES if you want to animate the selection and any change in position, NO if the change should be immediate.
        // 激活：如果你像激活选中单元，并且选择任意位置，那么可以选择是，不是，就是不激活
        NSIndexPath *selectedIndexPath = [NSIndexPath indexPathForRow:0 inSection:0];
        [self.rightTableView selectRowAtIndexPath:selectedIndexPath animated:YES scrollPosition:UITableViewScrollPositionNone];
    }else{
        // 全部关上
        for (NSInteger i=1; i<=numOfMenu;i++) {
            UIButton *tmpbutton=(UIButton*)[self viewWithTag:i];
            tmpbutton.imageView.transform=CGAffineTransformMakeRotation(0);
        }
    }
    [self animateBackGroundView:self.backGroundView show:!_show complete:^{
        [self animateTableViewShow:!_show complete:^{
            
            [self tableView:self.rightTableView didSelectRowAtIndexPath:[NSIndexPath indexPathForRow:0 inSection:0]];
            _show=!_show;
        }];
    }];
    [_rightTableView reloadData];
}

// 点击背景 显示动画
- (void)backgroundTapped:(UITapGestureRecognizer *)paramSender
{
    // 点击背景还能干啥呢？关闭呗
    
    [self animateBackGroundView:_backGroundView show:!_show complete:^{
        [self animateTableViewShow:!_show complete:^{
             _show=!_show;
        }];
    }];
}

#pragma mark - table datasource
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
        return [self menu:self tableView:tableView numberOfRowsInSection:section];
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *identifier = @"DropDownMenuCell";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:identifier];
    if (!cell) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:identifier];
    }

    cell.textLabel.text = [self menu:self tableView:tableView titleForRowAtIndexPath:indexPath];

    if(tableView == _leftTableView){
        cell.backgroundColor = [UIColor whiteColor];
    }else{
        UIView *sView = [[UIView alloc] init];
        sView.backgroundColor = [UIColor whiteColor];
        cell.selectedBackgroundView = sView;
        
//    setSelected:animated:  设置选中项 ：激活
//        Sets the selected state of the cell, optionally animating the transition between states.
// 设置cell的选择状态，可以选择过度状态之间的动画
        [cell setSelected:YES animated:YES];
        cell.backgroundColor = [UIColor colorWithWhite:0.9 alpha:1.f];
    }
    cell.textLabel.font = [UIFont systemFontOfSize:14.0];
    cell.separatorInset = UIEdgeInsetsZero;
    return cell;
}


#pragma mark - tableview delegate
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
        if (tableView == self.leftTableView) {
            [self animateBackGroundView:_backGroundView show:NO complete:^{
                [self animateTableViewShow:NO complete:^{
                    
                    /*-----------------------------更改表头显示------------------------------*/
                    
                    UIButton *changeButton=(UIButton*)[self viewWithTag:currentSelectedMenudIndex];
                    UITableViewCell *tmpcell=[tableView cellForRowAtIndexPath:indexPath];
                    NSString *tmpString=tmpcell.textLabel.text;
                    [changeButton setTitle:tmpString forState:UIControlStateNormal];
                    _show =!_show;
                }];
            }];
        }
    
    [self menu:self tableView:tableView didSelectRowAtIndexPath:indexPath andCurrent:currentSelectedMenudIndex-1];
    
}


#pragma mark- 处理数据
- (NSInteger)menu:(DropDownClass *)menu tableView:(UITableView*)tableView numberOfRowsInSection:(NSInteger)section;
{
    if (tableView == menu.rightTableView) {
        return [[[dataArray objectAtIndex:currentSelectedMenudIndex-1] objectAtIndex:1] count];
    }else{
        return [CurrentArray count];
    }
}

- (NSString *)menu:(DropDownClass *)menu tableView:(UITableView*)tableView titleForRowAtIndexPath:(NSIndexPath *)indexPath
{
    if(tableView==menu.rightTableView)
    {
//        return cityArr[indexPath.row];
        return [[[dataArray objectAtIndex:currentSelectedMenudIndex-1]objectAtIndex:1] objectAtIndex:indexPath.row];
    }else{
        return [CurrentArray objectAtIndex:indexPath.row];
    }
}
/*--------------------------------点击右栏展示（刷新）左栏-----------------------------------*/
- (void)menu:(DropDownClass *)menu tableView:(UITableView*)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath andCurrent:(NSInteger)culm
{
    if(tableView == menu.rightTableView){
        menu.CurrentArray=[[[menu.dataArray objectAtIndex:culm] objectAtIndex:2]objectAtIndex:indexPath.row];
        [menu.leftTableView reloadData];
    }
}

-(NSMutableArray*)getData
{
    NSMutableArray *tmpArray=[NSMutableArray new];
    
    for (int i=1; i<=currentSelectedMenudIndex; i++) {
        UIButton *tmpbutton=(UIButton*)[self viewWithTag:i];
        NSString *tmpString=tmpbutton.titleLabel.text;
        [tmpArray addObject:tmpString];
    }
    return tmpArray;
}

https://git.oschina.net/zhengaoxing/DropDownMenuDemo-IOS

本文地址：http://blog.csdn.net/zhenggaoxing/article/details/42968555 

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