模型在 QTableView 中动态插入和删除行时的信号/插槽

Question

我在QTableview 的最后一列中插入QPushButton。使用该按钮，我将使用按钮释放信号和插槽handlebutton(int) 删除该特定行。

cpp代码：

MainWindow::MainWindow(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    QSortFilterProxyModel *model = new QSortFilterProxyModel(this);
    model = pCApp->guiClient()->getConnectionManagement()->getProxyModel();
    ui->tableView->setModel(model);
    connect(pCApp, SIGNAL(CloseOpenWindowsRequested()), SLOT(close()));
    connect(ui->tableView->model(), SIGNAL(rowsInserted(QModelIndex,int,int)), this, SLOT(onRowsNumberChanged()));
    connect(ui->tableView->model(), SIGNAL(rowsRemoved(QModelIndex,int,int)), this, SLOT(onRowsNumberChanged()));
    ui->tableView->setSortingEnabled(true);
    QPushButton *button;
    QSignalMapper *mapper = new QSignalMapper(this);
    QObject::connect(mapper, SIGNAL (mapped(int)), this, SLOT (handleButton(int)));
    for (int i = 0; i < model->rowCount(); i++)
    {
        button = new QPushButton;
        button->setText("Disconnect " + QString::number(i));
        button->setStyleSheet("QPushButton { color: #E5E5E5; }");
        ui->tableView->setIndexWidget(model->index(i,2, QModelIndex()), button);
        QObject::connect(button, SIGNAL(released()), mapper, SLOT(map()));
        connect(ui->tableView->model(), SIGNAL(rowsInserted(QModelIndex,int,int)), this, SLOT(onRowsNumberChanged()));
        connect(ui->tableView->model(), SIGNAL(rowsRemoved(QModelIndex,int,int)), this, SLOT(onRowsNumberChanged()));
        mapper->setMapping(button, i);
    }
    setAttribute(Qt::WA_DeleteOnClose);
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::handleButton(int row)
{
    this->ui->tableView->model()->removeRow(row);
}

void MainWindow::onRowsNumberChanged()
{
    QSortFilterProxyModel *model = new QSortFilterProxyModel(this);
    model = pCApp->guiClient()->getConnectionManagement()->getProxyModel();
    ui->tableView->setModel(model);
    ui->tableView->setSortingEnabled(true);
    QPushButton *button;
    QSignalMapper *mapper = new QSignalMapper(this);
    QObject::connect(mapper, SIGNAL (mapped(int)), this, SLOT (handleButton(int)));
    for (int i = 0; i < model->rowCount(); i++)
    {
        button = new QPushButton;
        button->setText("Disconnect " + QString::number(i));
        button->setStyleSheet("QPushButton { color: #E5E5E5; }");
        ui->tableView->setIndexWidget(model->index(i,2, QModelIndex()), button);
        QObject::connect(button, SIGNAL(released()), mapper, SLOT(map()));
        mapper->setMapping(button, i);
    }

}

hpp 代码：

#ifndef MAINWINDOW_HPP
#define MAINWINDOW_HPP

namespace Ui {
class MainWindow;
}

class MainWindow : public QDialog
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();
public slots:
    void onLanguageChanged();
    void handleButton(int row);
    void onRowsNumberChanged();

private:
    Ui::MainWindow *ui;
};

#endif // MAINWINDOW_HPP

在正常情况下，代码运行正常。但是，当插入新行和/或删除旧行时，按钮不会按需要出现在最后一列中。我尝试使用信号 -

connect(ui->tvServStat->model(), SIGNAL(rowsInserted(QModelIndex,int,int)), this, SLOT(onRowsNumberChanged()));

connect(ui->tvServStat->model(), SIGNAL(rowsRemoved(QModelIndex,int,int)), this, SLOT(onRowsNumberChanged()));

两个插槽，我与onRowsNumberChanged() 保持相同，我再次尝试在最后一列中插入按钮。我的想法是可能是行数正在改变，所以我正在重新实现相同的逻辑。但是，它不起作用。

任何人都可以帮助纠正我的逻辑或其他逻辑以实现此功能。提前致谢！

Answer 1

您应该为该列使用delegate。这样，视图会自动处理行的创建/删除。见this question

---

您的代码还有一些其他问题：

1. 您多次连接rowsInserted/rowsRemoved
2. 在您的代码中，您可以创建多个信号映射器来映射相同类型的连接。这不是它的预期用途
3. onRowsNumberChanged 循环的重复

Answer 2

要使用小部件解决您的问题，您可以使用以下方法。它使用 Qt 5 的新连接语法和 C++ lambda，因此可以消除对信号映射器的需要：

#include "form.h"
#include <QtWidgets>
#include <QStandardItemModel>

Form::Form(QWidget *parent) :
    QWidget(parent)
{
    QPushButton *b = new QPushButton("add row");
    m_tree = new QTreeView(this);
    QBoxLayout *l = new QVBoxLayout(this);
    l->addWidget(m_tree, 1);
    l->addWidget(b);

    QStandardItemModel *m = new QStandardItemModel(0, 3, this);
    m_tree->setModel(m);

    connect(b, &QPushButton::clicked, this, &Form::addRow);
    connect(m, SIGNAL(rowsInserted(QModelIndex,int,int)), this, SLOT(addItemButtons()));
    connect(m, SIGNAL(rowsRemoved(QModelIndex,int,int)), this, SLOT(addItemButtons()));
}

Form::~Form()
{
}

void Form::addRow()
{
    m_tree->model()->insertRow(m_tree->model()->rowCount());
}

void Form::addItemButtons()
{
    for (int i = 0; i < m_tree->model()->rowCount(); ++i) {
        auto idx = m_tree->model()->index(i, 2);
        QPushButton *b = new QPushButton("X");
        b->setStyleSheet("QPushButton {color: #E5E5E5;}");
        m_tree->setIndexWidget(idx, b);
        connect(b, &QPushButton::clicked, [=](){
            m_tree->model()->removeRow(i);
        });
    }
}