QT-ComboBox

一、QComboBox

The QComboBox widget is a combined button and popup list.(來源：官網)

QComboBox部件由一個按鈕和彈出列表組成

二、常用函數

函數返回值	函數
void	addItem(const QString &text, const QVariant &userData = QVariant())
void	addItem(const QIcon &icon, const QString &text, const QVariant &userData = QVariant())
void	addItems(const QStringList &texts)
QCompleter *	completer() const
int	count() const
QVariant	currentData(int role = Qt::UserRole) const
int	currentIndex() const
QString	currentText() const
bool	duplicatesEnabled() const
int	findData(const QVariant &data, int role = Qt::UserRole, Qt::MatchFlags flags = static_cast<Qt::MatchFlags> ( Qt::MatchExactly | Qt::MatchCaseSensitive )) const
int	findText(const QString &text, Qt::MatchFlags flags = static_cast<Qt::MatchFlags> ( Qt::MatchExactly | Qt::MatchCaseSensitive )) const
bool	hasFrame() const
virtual void	hidePopup()
QSize	iconSize() const
void	insertItem(int index, const QString &text, const QVariant &userData = QVariant())
void	insertItem(int index, const QIcon &icon, const QString &text, const QVariant &userData = QVariant())
void	insertItems(int index, const QStringList &list)
InsertPolicy	insertPolicy() const
void	insertSeparator(int index)
bool	isEditable() const
QVariant	itemData(int index, int role = Qt::UserRole) const
QAbstractItemDelegate *	itemDelegate() const
QIcon	itemIcon(int index) const
QString	itemText(int index) const
QLineEdit *	lineEdit() const
int	maxCount() const
int	maxVisibleItems() const
int	minimumContentsLength() const
QAbstractItemModel *	model() const
int	modelColumn() const
void	removeItem(int index)
QModelIndex	rootModelIndex() const
void	setCompleter(QCompleter *completer)
void	setDuplicatesEnabled(bool enable)
void	setEditable(bool editable)
void	setFrame(bool)
void	setIconSize(const QSize &size)
void	setInsertPolicy(InsertPolicy policy)
void	setItemData(int index, const QVariant &value, int role = Qt::UserRole)
void	setItemDelegate(QAbstractItemDelegate *delegate)
void	setItemIcon(int index, const QIcon &icon)
void	setItemText(int index, const QString &text)
void	setLineEdit(QLineEdit *edit)
void	setMaxCount(int max)
void	setMaxVisibleItems(int maxItems)
void	setMinimumContentsLength(int characters)
void	setModel(QAbstractItemModel *model)
void	setModelColumn(int visibleColumn)
void	setRootModelIndex(const QModelIndex &index)
void	setSizeAdjustPolicy(SizeAdjustPolicy policy)
void	setValidator(const QValidator *validator)
void	setView(QAbstractItemView *itemView)
virtual void	showPopup()
SizeAdjustPolicy	sizeAdjustPolicy() const
const QValidator *	validator() const
QAbstractItemView *	view() const

三、常用函數解釋

添加數據（帶圖片）

源碼

// 添加圖片
QIcon icon("F:/qiangu/qtnull/Null/ICON/icon.jpg");
ui->comboBox->addItem(icon, QString("First"));
ui->comboBox->addItem(icon, QString("Second"));
ui->comboBox->addItem(icon, QString("Third"));
ui->comboBox->addItem(icon, QString("Four"));

// 批量添加
QStringList strList;
ui->comboBox->addItems(strList);

允許編輯、不可編輯、文字居中（下拉框和按鈕文字）

源碼

QLineEdit *lineEdit = new QLineEdit();
lineEdit->setReadOnly(true);  //僅查看
//lineEdit->setEnabled(true); //可編輯
lineEdit->setAlignment(Qt::AlignCenter);
ui->comboBox->setLineEdit(lineEdit);

for (int i = 0; i < ui->comboBox->count(); ++i) 
{
	ui->comboBox->setItemData(i, Qt::AlignCenter, Qt::TextAlignmentRole);
}

綁定View

QComboBox的Item設置屬性後，需要綁定View去實現（比如Item的高度修改）

源碼

QListView *ListView = new QListView();
ui->comboBox->setView(ListView);
ui->comboBox->view()->setVerticalScrollBarPolicy(Qt::ScrollBarAsNeeded);

實時刷新QComboBox數據

源碼

/// \brief 重寫showPopup()，每次顯示時，更新QComboBox的item數據
void NullComboBox::showPopup()
{
    QStringList listData;
    QComboBox::clear();
    QComboBox::addItems(listData);
    QComboBox::showPopup();
}

改變下拉列表位置

源碼

void NullComboBox::showPopup()
{
    QComboBox::showPopup();
    QWidget *popup = this->findChild<QFrame*>();
    //向下移動
    popup->move(popup->x(), popup->y() + 4);
    //向上彈出
    //popup->move(popup->x(), popup->y()-this->height()-popup->height());
}

總結

QComboBox的很多屬性沒有提供接口修改，需要使用到代理，有機會再總結