创建具有复选框的树型控件

本文章介绍如何创建具有复选框的树型控件。

    描述：当选中group1节点时，它的子节点会全部选中；当取消选择group1节点时，它的子节点的选中状态会全部被取消；而选中子节点时，父节点显示部分选中状态。

源码：widge.h

#ifndef WIDGET_H

#define WIDGET_H

#include <QWidget>

#include <QTreeWidgetItem>

#include <QGridLayout>

namespace Ui {

class Widget;

}

class Widget : public QWidget

{

    Q_OBJECT

public:

    explicit Widget(QWidget *parent = 0);

    ~Widget();

    void init();

    void updateParentItem(QTreeWidgetItem *item);

public slots:

    void treeItemChanged(QTreeWidgetItem *item, int colum);

private:

    Ui::Widget *ui;

    QTreeWidget *treeWidget;

    QGridLayout *gridLayout;

};

#endif // WIDGET_H

源码：widget.cpp

#include "widget.h"

#include "ui_widget.h"

#include <QTreeWidget>

#include <QDebug>

Widget::Widget(QWidget *parent) :

    QWidget(parent),

    ui(new Ui::Widget)

{

    ui->setupUi(this);

    treeWidget = new QTreeWidget(this);

    treeWidget->setHeaderLabel(tr("全选|部分选中|未选"));

    gridLayout = new QGridLayout(this);

    gridLayout->addWidget(treeWidget);

    init();

    connect(treeWidget, &QTreeWidget::itemChanged, this, &Widget::treeItemChanged); // qt5

//    connect(treeWidget, SIGNAL(itemChanged(QTreeWidgetItem*, int)), this, SLOT(treeItemChanged(QTreeWidgetItem*, int))); // qt4

}

Widget::~Widget()

{

    delete ui;

}

void Widget::init()

{

    treeWidget->clear();

    QTreeWidgetItem *group1 = new QTreeWidgetItem(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 *subItem13 = new QTreeWidgetItem(group1);

    subItem13->setFlags(Qt::ItemIsUserCheckable | Qt::ItemIsEnabled | Qt::ItemIsSelectable);

    subItem13->setText(0, "subItem13");

    subItem13->setCheckState(0, Qt::Unchecked);

    QTreeWidgetItem *subItem14 = new QTreeWidgetItem(group1);

    subItem14->setFlags(Qt::ItemIsUserCheckable | Qt::ItemIsEnabled | Qt::ItemIsSelectable);

    subItem14->setText(0, "subItem14");

    subItem14->setCheckState(0, Qt::Unchecked);

    QTreeWidgetItem *group2 = new QTreeWidgetItem(treeWidget);

    group2->setFlags(Qt::ItemIsUserCheckable | Qt::ItemIsEnabled | Qt::ItemIsSelectable);

    group2->setText(0, "group2");

    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, "subItem22");

    subItem22->setCheckState(0, Qt::Unchecked);

}

void Widget::treeItemChanged(QTreeWidgetItem *item, int colum)

{

    QString itemText = item->text(0);

    qDebug() << itemText;

    // select

    if(Qt::Checked == item->checkState(0)){

        QTreeWidgetItem *parent = item->parent();

        int count = item->childCount();

        if(count > 0){

            for(int i = 0; i < count; i++){

                // select subItem

                item->child(i)->setCheckState(0, Qt::Checked);

            }

        }else{

            // subItem

            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{

            // subItem

            updateParentItem(item);

        }

    }

}

void Widget::updateParentItem(QTreeWidgetItem *item)

{

    QTreeWidgetItem *parent = item->parent();

    if(parent == NULL){

        return;

    }

    // select subItem count

    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); // select some

    else if(selectedCount == childCount)

        parent->setCheckState(0, Qt::Checked);

}

效果如下：

案例源码以上传到：http://download.csdn.net/detail/qq_33218979/9905506