RATreeView的使用 '默认展开几层'

在使用RATreeView三方中其他的感觉没有太大的问题 包括数据的增删改查,下拉动画等等，但是最近使用RATreeView做项目，项目要求树形结构默认展开第一层，RATreeView默认却是收起的，无奈了之后，我就开始在这个RATreeView三方的源文件到处寻找 ，希望可以找到RATreeView提供给外界的API，当然了 结果是比较失望的，但是功夫不负有心人，问题终于在这里找个答案了 https://github.com/Augustyniak/RATreeView/issues/122

AFFF5216-7E04-40AB-952C-ED5DD4AED092.png

首先大致分析一下源文件：
RATreeView : 树形结构主体页面
RATreeView+TableViewDelegate : RATreeView的分类代理，目的是为了和RATableView绑定
RATableView: RATreeView的内置tab
RATreeNode :包含了item和expanded ，item相当于model expanded控制展开收起

主体代码

• 创建treeTab

- (RATreeView *)treeTab {
    if (!_treeTab) {
        _treeTab = [[RATreeView alloc] init];
        _treeTab.backgroundColor = [UIColor whiteColor];
        _treeTab.frame= CGRectMake(0, 0, ScreenW, TreeViewH);
        _treeTab.delegate = self;
        _treeTab.dataSource = self;
        _treeTab.separatorColor = BACKCOLOUR;
        [_treeTab registerNib:[UINib nibWithNibName:@"RaTreeViewCell" bundle:nil] forCellReuseIdentifier:@"RaTreeViewCell"];
    }
    return _treeTab;
}

• 设置数据

-(void)setArrData:(NSMutableArray *)arrData
{
    self.arr = @[].mutableCopy;
    _arrData = arrData;
   // 此处是构建model 然后加入数组
    [self checkParent:arrData];
    [_treeTab reloadData];
--------------默认展开第几层-------------------------------------------------------
    for (id item in [_treeTab itemsForRowsInRect:_treeTab.frame])
    {
        [_treeTab expandRowForItem:item expandChildren:NO withRowAnimation:RATreeViewRowAnimationNone];
    }
    _treeTab.frame= CGRectMake(0, -TreeViewH, ScreenW, TreeViewH);
}

• 代理

#pragma mark --- delegate
- (CGFloat)treeView:(RATreeView *)treeView heightForRowForItem:(id)item {
    return 50;
}
- (BOOL)treeView:(RATreeView *)treeView shouldExpandRowForItem:(id)item
{
     BOOL expanded = [treeView isCellForItemExpanded:item];
    return YES;
}
- (UITableViewCell *)treeView:(RATreeView *)treeView cellForItem:(id)item {
    
    //获取cell
    RaTreeViewCell *cell = [treeView dequeueReusableCellWithIdentifier:@"RaTreeViewCell"];
    
    //当前item
    MonitorTreeModel *model = item;
    cell.delegate = self;
    //当前层级
    NSInteger level = [treeView levelForCellForItem:item];
    //赋值
    [cell setCellBasicInfoWith:model.comName level:level children:model.children.count];
    if (model.isNoExpand == 0) {
        cell.iconView.image = [UIImage imageNamed:@"TreeAdd"];
        
    }else{
        cell.iconView.image = [UIImage imageNamed:@"TreeDeduct"];
    }
    if (model.children.count ==0)
    {
        cell.iconView.image = IMG(@"TreePoint");
    }
    return cell;
}
/**
 *  必须实现
 *  @param treeView treeView
 *  @param item    节点对应的item
 *  @return  每一节点对应的个数
 */
- (NSInteger)treeView:(RATreeView *)treeView numberOfChildrenOfItem:(id)item
{
    MonitorTreeModel *model = item;
    if (item == nil) {
        return self.arr.count;
    }
    return model.children.count;
}
/**
 *必须实现的dataSource方法
 *  @param treeView treeView
 *  @param index    子节点的索引
 *  @param item     子节点索引对应的item
 *  @return 返回 节点对应的item
 */
- (id)treeView:(RATreeView *)treeView child:(NSInteger)index ofItem:(id)item {
    MonitorTreeModel *model = item;
    if (item==nil) {
        return self.arr[index];
    }
    return model.children[index];
}

//cell的点击方法
- (void)treeView:(RATreeView *)treeView didSelectRowForItem:(id)item {
    
    RaTreeViewCell *cell = (RaTreeViewCell *)[treeView cellForItem:item];
    
    //当前点击的model
    MonitorTreeModel *model = item;
    
    model.isNoExpand = model.isNoExpand==0 ? 1 : 0;
    if (model.isNoExpand == 0) {
        cell.iconView.image = [UIImage imageNamed:@"TreeAdd"];
    }else{
        cell.iconView.image = [UIImage imageNamed:@"TreeDeduct"];
    }
    if (model.children.count ==0)
    {
        cell.iconView.image = IMG(@"TreePoint");
    }
}
//单元格是否可以编辑 默认是YES
- (BOOL)treeView:(RATreeView *)treeView canEditRowForItem:(id)item {
    
    return NO;
}

• 设置cell

//点击cell的按钮
- (IBAction)ClickDetail:(UIButton *)sender
{
    [self.delegate  ClickWithCell:self];
}
// 图标 文本的显示
- (void)setCellBasicInfoWith:(NSString *)title level:(NSInteger)level children:(NSInteger )children{

    self.titleLable.text = title;
        
    //每一层的布局
    CGFloat left = 10+level*30;
    
    //头像的位置
    CGRect  iconViewFrame = self.iconView.frame;
    
    iconViewFrame.origin.x = left;
    
    self.iconView.frame = iconViewFrame;
    
    //title的位置
    CGRect titleFrame = self.titleLable.frame;
    
    titleFrame.origin.x = 40+left;
    
    self.titleLable.frame = titleFrame;
}

参考文章：https://github.com/Augustyniak/RATreeView