QTreeWidget中的复选框使用

在树形结构中有时候需要在每项前添加复选框，能够进行勾选，复选框的添加可以使用tree本身的属性就行

 void QTreeWidgetItem::setCheckState ( int column, Qt::CheckState state )

Sets the item in the given column check state to be state.

 

添加完控件后，需要对树形结构的勾选操作做一些限定：

1、父项勾选后，子项自动全部勾选

2、子项部分勾选后，父项为部分选中状态

3、当子项全部勾选后，父项也会随之勾选

 

connect(tree,SIGNAL(itemChanged(QTreeWidgetItem*,int)),this,SLOT(treeItemChanged(QTreeWidgetItem*,int)));

 

void Count::treeItemChanged(QTreeWidgetItem *item, int column)
{
    QString itemText = item->text(0);
    if (item->checkState(0) == Qt::Checked)
        {
        QTreeWidgetItem *parent = item->parent();
        int cnt = item->childCount();
        if (cnt >0)
            {
            for (int i = 0;i < cnt;i++)
                {
                 item->child(i)->setCheckState(0,Qt::Checked);
            }
        }
        else
            {
            updateParentItem(item);
        }
    }
    else if (item->checkState(0) == Qt::Unchecked)
        {
        int cnt = item->childCount();
        if (cnt > 0)
            {
            for (int i = 0;i < cnt;i++)
                {
                item->child(i)->setCheckState(0,Qt::Unchecked);
            }
        }
        else
            {
            updateParentItem(item);
        }
    }
}
void Count::updateParentItem(QTreeWidgetItem *item)
{
    QTreeWidgetItem *parent = item->parent();
    if (parent == NULL)
    {
       return;
    }
    //选中的子节点个数
    int selectedCount = 0;
    int childCount = parent->childCount();
    for (int i = 0; i < childCount; i++)
    {
       QTreeWidgetItem *childItem = parent->child(i);
       if (childItem->checkState(0) == Qt::Checked)
       {
        selectedCount++;
       }
    }
    if (selectedCount <= 0)
    {
        //未选中状态
       parent->setCheckState(0, Qt::Unchecked);
    }
    else if (selectedCount > 0 && selectedCount < childCount)
    {
       //部分选中状态
       parent->setCheckState(0, Qt::PartiallyChecked);
    }
    else if (selectedCount == childCount)
    {
      //选中状态
       parent->setCheckState(0, Qt::Checked);
    }
}