C++ Qt 为 QTableView 使用自定义 QItemDelegate

Question

提问by arnm

I followed the Spin Box Delegate tutorial, which Qt provides, to try to implement my own QItemDelegate. It would be used to specify a QComboBoxto represent data in a QTableViewcell but it is not working.

我按照 Qt 提供的 Spin Box Delegate 教程尝试实现我自己的QItemDelegate. 它将用于指定 aQComboBox来表示QTableView单元格中的数据，但它不起作用。

My biggest problem is that I don't know when my QItemDelegateis going to be utilized.

我最大的问题是我不知道我什么时候QItemDelegate会被利用。

when itemModel->setData()is used or when itemModel->setItem(). I would suspect setItem()because I reimplemented a QItemDelegate(emphasis on the "Item") but the tutorial uses setData()and it works fine.
I know that if the specified QItemDelegatedoes not work it uses the default one but how do I now that the one I specified did not work?
when should I suspect for QTableViewto use my delegate. I would like to specify which delegates to use for each cell. Is this possible or does the QTableViewonly use one delegate throughout?
How would I specify the items to populate the QComboBoxonce it gets displayed by the QTableView?

何时itemModel->setData()使用或何时使用itemModel->setItem()。我会怀疑setItem()是因为我重新实现了一个QItemDelegate（强调“项目”），但本教程使用setData()并且工作正常。
我知道如果指定的QItemDelegate不起作用，它会使用默认的，但是现在我指定的不起作用怎么办？
我什么时候应该怀疑QTableView使用我的委托。我想指定每个单元格使用哪些委托。这是可能的还是QTableView整个过程中唯一使用一个代表？
QComboBox一旦它被显示，我将如何指定要填充的项目QTableView？

I implemented QItemDelegatehere:

我QItemDelegate在这里实施：

the part where I try to add the cell which is suppose to use the QComboBoxis under the comment "Enabled" in mainwindow.cpp further down this post.

我尝试添加假设使用的单元格的部分QComboBox在 mainwindow.cpp 中的注释“已启用”下，在这篇文章的下方。

qcomboboxitemdelegate.h

#ifndef QCOMBOBOXITEMDELEGATE_H
#define QCOMBOBOXITEMDELEGATE_H

#include <QItemDelegate>
#include <QComboBox>

class QComboBoxItemDelegate : public QItemDelegate
{
    Q_OBJECT

public: 

    explicit QComboBoxItemDelegate(QObject *parent = 0);

    QWidget* createEditor(QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index);
    void setEditorData(QWidget *editor, const QModelIndex &index);
    void setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index);
    void updateEditorGeometry(QWidget *editor, const QStyleOptionViewItem &option,     const QModelIndex &index);

signals:

private:

};

#endif // QCOMBOBOXITEMDELEGATE_H

qcomboboxitemdelegate.cpp

#include "qcomboboxitemdelegate.h"
#include <QDebug>

QComboBoxItemDelegate::QComboBoxItemDelegate(QObject *parent)
: QItemDelegate(parent)
{

}

QWidget* QComboBoxItemDelegate::createEditor(QWidget *parent, const   QStyleOptionViewItem &option, const QModelIndex &index) {
    // create widget for use
    QComboBox* comboBox = new QComboBox(parent);
    return comboBox;
}

void QComboBoxItemDelegate::setEditorData(QWidget *editor, const QModelIndex &index) {
    // update model widget
    QString value = index.model()->data(index, Qt::EditRole).toString();
    qDebug() << "Value:" << value;
    QComboBox* comboBox = static_cast<QComboBox*>(editor);
    comboBox->setCurrentIndex(comboBox->findText(value));
}

void QComboBoxItemDelegate::setModelData(QWidget *editor, QAbstractItemModel *model,   const QModelIndex &index) {
    // store edited model data to model
    QComboBox* comboBox = static_cast<QComboBox*>(editor);
    QString value = comboBox->currentText();
    model->setData(index, value, Qt::EditRole);
}

void QComboBoxItemDelegate::updateEditorGeometry(QWidget *editor, const     QStyleOptionViewItem &option, const QModelIndex &index) {
    editor->setGeometry(option.rect);
}

mainwindow.cpp : this is where I initialize the QStandardItemModel

mainwindow.cpp ：这是我初始化 QStandardItemModel

void MainWindow::init() {
    itemModel = new QStandardItemModel(this);
}

void MainWindow::setupUi() {
    this->setWindowTitle("QAlarmClock");        
    QStringList labelList;
    labelList << "Alarm Name" << "Time" << "Enabled";
    itemModel->setHorizontalHeaderLabels(labelList);    
    ui->tableView->setModel(itemModel);
    ui->tableView->horizontalHeader()->setSectionResizeMode(QHeaderView::Stretch);
    ui->tableView->setItemDelegate(comboBoxItemDelegate);
}

void MainWindow::on_actionNew_triggered() {
    alarmDialog = new AlarmDialog(this);
    connect(alarmDialog, SIGNAL(on_close()), this, SLOT(on_alarmDialog_close()));
    alarmDialog->exec();
}

mainwindow.cpp : this is where I update QStandardItemModel

mainwindow.cpp ：这是我更新的地方 QStandardItemModel

void MainWindow::on_alarmDialog_close() {
    QString alarmName = alarmDialog->getAlarmName();
    QDateTime alarmDateTime = alarmDialog->getDateTime();

    itemModel->insertRow(itemModel->rowCount());
    int rowCount = itemModel->rowCount();

    // Alarm Name
    QStandardItem* alarmItem = new QStandardItem(QIcon("res/alarmclock.ico"),  alarmName);
    itemModel->setItem(rowCount - 1 , 0, alarmItem);

    // Date Time
    QStandardItem* dateTimeItem = new QStandardItem();
    dateTimeItem->setText(alarmDateTime.toString());
    dateTimeItem->setEditable(false);
    itemModel->setItem(rowCount - 1, 1, dateTimeItem);

    // Enabled
    QStandardItem* enabledItem = new QStandardItem();
    QList<QStandardItem*> optionList;
    optionList << new QStandardItem("Enabled") << new QStandardItem("Disabled");
    enabledItem->appendRows(optionList);
    itemModel->setItem(rowCount - 1, 2, enabledItem);
}

Edit 1

编辑 1

qcomboboxdelegate.cpp

QWidget* QComboBoxItemDelegate::createEditor(QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) {
    // create widget for use
    qDebug() << "Column: " << index.column();
    if (index.column() == 2) {
        QComboBox* comboBox = new QComboBox(parent);
        QStringList values;
        values << "Enabled" << "Disabled";
        comboBox->addItems(values);
        return comboBox;
    } else {
        return QItemDelegate::createEditor(parent, option, index);
    }
}

mainwindow.cpp

主窗口.cpp

void MainWindow::on_alarmDialog_close() {
    QList<QStandardItem*> row;

    QString alarmName = alarmDialog->getAlarmName();
    QDateTime alarmDateTime = alarmDialog->getDateTime();
    QString status = "Enabled";

    // Alarm Name
    QStandardItem* alarmItem = new QStandardItem(QIcon("res/alarmclock.ico"), alarmName);
    row << alarmItem;

    // Date Time
    QStandardItem* dateTimeItem = new QStandardItem();
    dateTimeItem->setText(alarmDateTime.toString());
    dateTimeItem->setEditable(false);
    row << dateTimeItem;

    // Enabled
    QStandardItem* statusItem = new QStandardItem(status);
    row << statusItem;

    itemModel->appendRow(row);
}

Answer 1

采纳答案by hank

First, you should have a description of your model columns:

首先，您应该对模型列进行描述：

enum Columns
{
    COL_NAME,
    COL_TIME,
    COL_STATUS
}

Your delegate should only work for the last column.

您的委托应该只适用于最后一列。

Here is an example of how you can populate your model:

以下是如何填充模型的示例：

for (int i = 0; i < 5; ++i)
{
    QStandardItem *itemName = new QStandardItem(QString("name %1").arg(i));
    QStandardItem *itemTime = new QStandardItem(QString("time %1").arg(i));

    QString status;
    if (i % 2 == 0)
    {
        status = "Enabled";
    }
    else
    {
        status = "Disabled";
    }

    QStandardItem *itemStatus = new QStandardItem(status);

    QList<QStandardItem*> row;
    row << itemName << itemTime << itemStatus;

    model->appendRow(row);
}

As I said, your delegate should only work for the last column. So all methods you have reimplemented should have a column check like this:

正如我所说，您的委托应该只适用于最后一列。所以你重新实现的所有方法都应该有一个这样的列检查：

QWidget* QComboBoxItemDelegate::createEditor(QWidget *parent, 
                            const QStyleOptionViewItem &option, 
                            const QModelIndex &index) 
{
    if (index.column() == COL_STATUS)
    {
        QStringList values;
        values << "Enabled" << "Disabled";

        QComboBox* comboBox = new QComboBox(parent);
        comboBox->addItems(values);
        return comboBox;
    }
    else
    {
        return QItemDelegate::createEditor(parent, option, index);
    }
}

You should add this check to the other methods: if the current column is not the status column, the base class (QItemDelegate) implementation should be used.

您应该将此检查添加到其他方法：如果当前列不是状态列，QItemDelegate则应使用基类 ( ) 实现。

Then you set your delegate to your view:

然后您将委托设置为您的视图：

ui->tableView->setItemDelegate(new ComboBoxDelegate);

If you do everything right, a combo Box will appear in the last column if you try to edit its values.

如果一切顺利，当您尝试编辑其值时，最后一列将出现一个组合框。

Answer 2

回答by arnm

So I figured out that I did not override the correct function prototypes..! I forgot that they had const in the prototype meaning that I was not overriding any functions so it was using the default ones. Here are the correct virtual functions that have to be re-implemented: http://qt-project.org/doc/qt-5.0/qtwidgets/qitemdelegate.html

所以我发现我没有覆盖正确的函数原型..！我忘了他们在原型中有 const 意味着我没有覆盖任何函数，所以它使用的是默认函数。以下是必须重新实现的正确虚拟功能：http: //qt-project.org/doc/qt-5.0/qtwidgets/qitemdelegate.html

Answer 3

回答by CodeLurker

Even more simply; I found QTableView::setItemDelegateForColumn() to work admirably for a column. For example, in your MainWindow, you could make a member:

更简单；我发现 QTableView::setItemDelegateForColumn() 非常适合用于列。例如，在您的 MainWindow 中，您可以创建一个成员：

QComboBoxItemDelegate dgtComboDelegate;

Then, in your ctor, or init(), you could have

然后，在您的 ctor 或 init() 中，您可以拥有

ui->tableView->setItemDelegateForColumn(2, dgtComboDelegate);

If you wanted that to happen for a single cell, that's when you need to test on the index.column() and index.row().

如果您希望单个单元格发生这种情况，那么您需要在 index.column() 和 index.row() 上进行测试。

You know, you don't have to create a QTableView to do this either. E.g., see the ?:

您知道，您也不必创建 QTableView 来执行此操作。例如，看到？：

Qt - Centering a checkbox in a QTable

Qt - 将 QTable 中的复选框居中

The OP doesn't give the declaration for a table widget or view; but it does have the QTableView tag. It should work equally well for either.

OP 没有给出表格小部件或视图的声明；但它确实有 QTableView 标签。它应该同样适用于任何一个。

In the latter case, you can do ui->tableWidget->setItemDelegateForColumn(2, dgtComboDelegate);and never have to make your own model. Just use setData() on the items you create (or even later, for that matter,) to initialize their values.

在后一种情况下，您可以ui->tableWidget->setItemDelegateForColumn(2, dgtComboDelegate);并且永远不必制作自己的模型。只需在您创建的项目上使用 setData()（或者甚至稍后，就此而言）来初始化它们的值。

C++ Qt 为 QTableView 使用自定义 QItemDelegate

提问by arnm

采纳答案by hank

回答by arnm

回答by CodeLurker

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C++ Qt 为 QTableView 使用自定义 QItemDelegate

提问by arnm

采纳答案by hank

回答by arnm

回答by CodeLurker

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