Qt listView添加复选框，可全选

要在Qt ListView中添加复选框并实现全选功能，需要执行以下步骤：

1. 创建一个自定义的QAbstractListModel或QStandardItemModel来作为数据模型。

2. 在数据模型中添加一个bool类型的属性来表示每个项目是否选中。

3. 在ListView的delegate中添加一个QCheckBox来显示每个项目的选中状态。

4. 创建一个全选/取消全选按钮并连接到相应的槽函数。

5. 在槽函数中遍历所有项目并设置它们的选中状态。

以下是一个示例代码：

// 自定义数据模型
class MyModel : public QAbstractListModel
{
public:
    struct Item {
        QString name;
        bool selected;
    };

    MyModel(QObject *parent = nullptr) : QAbstractListModel(parent) {}

    int rowCount(const QModelIndex &parent = QModelIndex()) const override {
        return m_items.count();
    }

    QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override {
        if (!index.isValid() || index.row() >= m_items.count())
            return QVariant();
        if (role == Qt::DisplayRole || role == Qt::EditRole)
            return m_items.at(index.row()).name;
        if (role == Qt::CheckStateRole)
            return m_items.at(index.row()).selected ? Qt::Checked : Qt::Unchecked;
        return QVariant();
    }

    Qt::ItemFlags flags(const QModelIndex &index) const override {
        if (!index.isValid() || index.row() >= m_items.count())
            return Qt::NoItemFlags;
        return Qt::ItemIsEnabled | Qt::ItemIsSelectable | Qt::ItemIsEditable | Qt::ItemIsUserCheckable;
    }

    bool setData(const QModelIndex &index, const QVariant &value, int role = Qt::EditRole) override {
        if (!index.isValid() || index.row() >= m_items.count())
            return false;
        if (role == Qt::CheckStateRole) {
            m_items[index.row()].selected = value.toBool();
            emit dataChanged(index, index, {role});
            return true;
        }
        if (role == Qt::EditRole) {
            m_items[index.row()].name = value.toString();
            emit dataChanged(index, index, {role});
            return true;
        }
        return false;
    }

    QList<Item> items() const { return m_items; }

    void setItems(const QList<Item> &items) {
        beginResetModel();
        m_items = items;
        endResetModel();
    }

    void selectAll(bool selected) {
        for (int i = 0; i < m_items.count(); ++i) {
            if (m_items[i].selected != selected) {
                m_items[i].selected = selected;
                emit dataChanged(index(i), index(i), {Qt::CheckStateRole});
            }
        }
    }

private:
    QList<Item> m_items;
};

// ListView的delegate
class MyDelegate : public QStyledItemDelegate
{
public:
    MyDelegate(QObject *parent = nullptr) : QStyledItemDelegate(parent) {}

    QWidget *createEditor(QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const override {
        QCheckBox *checkBox = new QCheckBox(parent);
        checkBox->setCheckState(index.data(Qt::CheckStateRole).toBool() ? Qt::Checked : Qt::Unchecked);
        return checkBox;
    }

    void setEditorData(QWidget *editor, const QModelIndex &index) const override {
        QCheckBox *checkBox = qobject_cast<QCheckBox *>(editor);
        checkBox->setCheckState(index.data(Qt::CheckStateRole).toBool() ? Qt::Checked : Qt::Unchecked);
    }

    void setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const override {
        QCheckBox *checkBox = qobject_cast<QCheckBox *>(editor);
        model->setData(index, checkBox->isChecked(), Qt::CheckStateRole);
    }
};

// MainWindow中的代码
MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent), ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    // 创建数据模型并设置ListView的model和delegate
    m_model = new MyModel(this);
    ui->listView->setModel(m_model);
    ui->listView->setItemDelegate(new MyDelegate(this));

    // 添加测试数据
    QList<MyModel::Item> items;
    items.append({"Item 1", false});
    items.append({"Item 2", false});
    items.append({"Item 3", false});
    items.append({"Item 4", false});
    m_model->setItems(items);

    // 创建全选/取消全选按钮并连接到槽函数
    QPushButton *selectAllButton = new QPushButton("Select All", this);
    ui->mainToolBar->addWidget(selectAllButton);
    connect(selectAllButton, &QPushButton::clicked, this, &MainWindow::onSelectAllClicked);
}

void MainWindow::onSelectAllClicked()
{
    m_model->selectAll(true);
}