QT--复选框树形控件的使用

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在Qt中树形控件是QTreeWidget,控件里的树节点为QTreeWidgetItem。控件如下：
这里写图片描述

具体方法：

1. 创建Qt Gui应用，基类选择“QWidget”，类名为“Widget”2. 在界面文件"widget.ui"中拖拽出一个QTreeWidget。3. 头文件"widget.h"中添加：

    #include <QTreeWidgetItem>

      类Widget声明中添加代码：

    public:          void init();          void updateParentItem(QTreeWidgetItem* item);    public slots:          void treeItemChanged(QTreeWidgetItem* item, int colum);

4.在“Widget.cpp”中的类Witget构造函数中添加：

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

 各个函数具体代码：

void Widget::init(){    ui->treeWidget->clear();    QTreeWidgetItem *group1 = new QTreeWidgetItem(ui->treeWidget);    group1->setText(0,"group1");    group1->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable);    group1->setCheckState(0,Qt::Unchecked);    QTreeWidgetItem *subItem11 = new QTreeWidgetItem(group1);    subItem11->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable);    subItem11->setText(0,"subItem11");    subItem11->setCheckState(0,Qt::Unchecked);    QTreeWidgetItem *subItem12 = new QTreeWidgetItem(group1);    subItem12->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable);    subItem12->setText(0,"subItem12");    subItem12->setCheckState(0,Qt::Unchecked);    QTreeWidgetItem *group2 = new QTreeWidgetItem(ui->treeWidget);    group2->setText(0,"group2");    group2->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable);    group2->setCheckState(0,Qt::Unchecked);    QTreeWidgetItem *subItem21 = new QTreeWidgetItem(group2);    subItem21->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable);    subItem21->setText(0,"subItem21");    subItem21->setCheckState(0,Qt::Unchecked);    QTreeWidgetItem *subItem22 = new QTreeWidgetItem(group2);    subItem22->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable);    subItem22->setText(0,"subIteml2");    subItem22->setCheckState(0,Qt::Unchecked);}

void Widget::treeItemChanged(QTreeWidgetItem *item, int colum){    QString itemText = item->text(0);    if (Qt::Checked == item->checkState(0))    {        QTreeWidgetItem* parent = item->parent();        int count = item->childCount();        if (count > 0)        {            for (int i = 0; i<count; i++)            {                item->child(i)->setCheckState(0,Qt::Checked);            }        }        else        {            updateParentItem(item);        }    }    else if (Qt::Unchecked == item->checkState(0))    {        int count = item->childCount();        if (count > 0)        {            for (int i = 0; i<count; i++)            {                item->child(i)->setCheckState(0,Qt::Unchecked);            }        }        else        {            updateParentItem(item);        }    }}

void Widget::updateParentItem(QTreeWidgetItem *item){    QTreeWidgetItem *parent = item->parent();    if (parent == NULL)    {        return;    }    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 )    {        parent->setCheckState(0,Qt::Unchecked);    }    else if (selectedCount > 0 && selectedCount < childCount)    {        parent->setCheckState(0,Qt::PartiallyChecked);    }    else if (selectedCount == childCount)    {        parent->setCheckState(0,Qt::Checked);    }}

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