QTreeWidget更新后保存节点的展开状态

class Xx : public QWidget

{

  Q_OBJECT

  struct ItemState{

    ItemState();

    int _id;

    bool _isExpend;

  };

public:

  Xx(QWidget *parent = 0);

  ~Xx();

  void updateTree();

private:

  void saveItemState();

  void popItemState();

  const ItemState itemState(int id);

private:

  Ui::Xx ui;

  QVector<ItemState> _itemState;

};

　　

Xx::ItemState::ItemState(){

  _isExpend = true;

  _id = -1;

}

void Xx::updateTree(){

  saveItemState();//更新前保存展开状态

  ui.treeWidget->clear();

  QTreeWidgetItem *rootItem = new QTreeWidgetItem(ui.treeWidget);

  rootItem->setText(0, "xx");

  rootItem->setData(0, Qt::UserRole,QString::number(id));

  rootItem->setExpanded(true);

  popItemState();//恢复展开状态

}

void Xx::saveItemState(){

  _itemState.clear();

  QTreeWidgetItemIterator it(ui.treeWidget);

  while (*it){

    ItemState itemState;

    itemState._id = (*it)->data(0, Qt::UserRole).toInt();

    itemState._isExpend = (*it)->isExpanded();

    _itemState.push_back(itemState);

    ++it;

  }

}

void Xx::popItemState(){

  QTreeWidgetItemIterator it(ui.treeWidget);

  QTreeWidgetItem *curItem(*it);

  while (*it){

    ItemState state = itemState((*it)->data(0, Qt::UserRole).toInt());

    if(state.id != -1){

      (*it)->setExpanded(state._isExpend);

    }

    ++it;

  }

}

const ShowCtrlWgt::ItemState ShowCtrlWgt::itemState(int id){

  ItemState state;

  for each (ItemState var in _itemState){

    if (var._id == id)

      return var;

  }

  return state;

}

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