QTreeWidget 右键菜单，复选框 及其他

一、

添加节点

void AddTreeItem(QTreeWidget *pTree, QTreeWidgetItem* parentItem, QString strItemTxt)
{
    QString txt;
    QTreeWidgetItem *item = new QTreeWidgetItem(parentItem);
    item->setFlags(item->flags()|Qt::ItemIsUserCheckable);
    item->setCheckState(0, Qt::Unchecked);
    item->setText(0, strItemTxt);
//    item->setData(0, Qt::UserRole, QString::number(nType));
//    item->setIcon(0, QIcon(QStringLiteral(":image/group.png")));
    item->setWhatsThis(0, strItemTxt);

    pTree->expandItem(parentItem);
}

void InitTree()
{
    ui->treeWidget->header()->setHidden(1);//隐藏最顶上的表头
    QTreeWidgetItem* topItem = new QTreeWidgetItem;
    topItem->setFlags(topItem->flags()|Qt::ItemIsUserCheckable);
    topItem->setCheckState(0, Qt::Unchecked);
    topItem->setText(0, "目标列表");
    ui->treeWidget->addTopLevelItem(topItem);

    AddTreeItem(ui->treeWidget, topItem, "飞机");
    AddTreeItem(ui->treeWidget, topItem, "大炮");
    AddTreeItem(ui->treeWidget, topItem, "坦克");

    connect(ui->treeWidget, SIGNAL(itemChanged(QTreeWidgetItem*,int)), this, SLOT(TreeItemChanged(QTreeWidgetItem*,int)));

}

 

一、

详细说一下QTreeWidget右键菜单的使用。

在mainwindow中，添加变量

QTreeWidget* m_tree;

为了使用右键菜单，需要设置

m_tree->setContextMenuPolicy(Qt::CustomContextMenu);

定义槽函数：

ShowContextMenu(const QPoint&)；

connect(m_tree, SIGNAL(customContextMenuRequested(const QPoint&)), this, SLOT(ShowContextMenu(const QPoint&)));

在槽函数中：

QTreeWidgetItem *item = m_tree->itemAt(point); //可得到右键条目
    if(item)
    {
        m_contextMenu->exec(QCursor::pos());//右键菜单
    }

这里简单叙述了过程。

 二、

树结构使用复选框

参考：https://www.cnblogs.com/doubleeleven/articles/3894250.html

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);
    }
}