Qt为QTableView使用自定义QItemDelegate

Question

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

我最大的问题是我不知道什么时候QItemDelegate会被利用.

• 何时itemModel->setData()使用或何时使用itemModel->setItem().我怀疑setItem()是因为我重新实现了QItemDelegate(强调"项目"),但教程使用setData()并且它工作正常.

• 我知道,如果指定QItemDelegate不起作用,它使用默认值,但我现在怎么说我指定的那个不起作用？

• 什么时候我应该怀疑QTableView使用我的代表.我想指定每个单元格使用哪些代理.这是可能的还是QTableView唯一使用一个代表？

• 如何将我指定的项目来填充QComboBox一旦获得通过所显示的QTableView？

我QItemDelegate在这里实现:

• 我尝试添加要假设使用的单元格的部分QComboBox位于mainwindow.cpp中的注释"Enabled"下面.

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:这是我初始化的地方 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: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);
}

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

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

首先,您应该有模型列的描述:

enum Columns
{
    COL_NAME,
    COL_TIME,
    COL_STATUS
}

您的代表应仅适用于最后一列.

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);
}

正如我所说,你的代表应该只为最后一栏工作.因此,您重新实现的所有方法都应该进行如下列检查:

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);
    }
}

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

然后将代理设置为您的视图:

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

如果你做的一切正确,如果你试图编辑它的值,组合框将出现在最后一列.