QT学习---自绘QlistWidget(增加编辑功能)

一、

继续完善上一篇的QlistWidget的自绘操作，为其增加编辑功能：

主要注意两点：

1、设置QlistWidget的每一项具有编辑功能：

QListWidgetItem* item1 = new QListWidgetItem;
	item1->setFlags(Qt::ItemIsEnabled|Qt::ItemIsEditable|Qt::ItemIsSelectable);

2、编辑后文本可能显示不全，此时要进行文本宽度的测量，然后根据实际宽度进行绘制。

二、实例代码

ListWidget::ListWidget(QWidget *parent, Qt::WFlags flags)
	: QMainWindow(parent, flags)
{
	ui.setupUi(this);

	
	QListWidgetItem* item1 = new QListWidgetItem;
	item1->setFlags(Qt::ItemIsEnabled|Qt::ItemIsEditable|Qt::ItemIsSelectable);
	QListWidgetItem* item2 = new QListWidgetItem;
	item2->setFlags(Qt::ItemIsEnabled|Qt::ItemIsEditable|Qt::ItemIsSelectable);

	item1->setData(Qt::DecorationRole,QIcon(":/ListWidget/Resources/Save.png"));
	item1->setData(Qt::DisplayRole,"Save");
	item1->setData(Qt::UserRole + 1,"This is Icon of Sage");
	item1->setData(Qt::UserRole + 2,":/ListWidget/Resources/Save.png");

	item2->setData(Qt::DecorationRole,QIcon(":/ListWidget/Resources/grab.png"));
	item2->setData(Qt::DisplayRole,"Grab");
	item2->setData(Qt::UserRole + 1,"This is Icon of Grab");
	item2->setData(Qt::UserRole + 2,":/ListWidget/Resources/grab.png");

	ui.listWidget->addItem(item1);
	ui.listWidget->addItem(item2);

	ui.listWidget->setItemDelegate(new MyItemPainter(ui.listWidget));
	
	//方法二:采用Model/View架构的方式
	/*
	QAbstractItemModel* mode = ui.listWidget->model();
	mode->insertRow(0);
	mode->setData(mode->index(0,0),"Save",Qt::DisplayRole);
	mode->setData(mode->index(0,0),"This is the Save Icon",Qt::ToolTipRole);
	mode->setData(mode->index(0,0),"Save Icon of User",Qt::UserRole);
	mode->setData(mode->index(0,0),QIcon(":/ListWidget/Resources/Save.png"),Qt::DecorationRole);

	mode->insertRow(1);
	mode->setData(mode->index(1,0),"Grab",Qt::DisplayRole);
	mode->setData(mode->index(1,0),"This is the Grab Icon",Qt::ToolTipRole);
	mode->setData(mode->index(1,0),"Grab Icon of User",Qt::UserRole);
	mode->setData(mode->index(1,0),QIcon(":/ListWidget/Resources/grab.png"),Qt::DecorationRole);
	*/
}

#ifndef MYITEMPAINTER_H
#define MYITEMPAINTER_H

#include <QStyledItemDelegate>

class MyItemPainter : public QStyledItemDelegate
{
	Q_OBJECT

public:
	MyItemPainter(QWidget *parent);
	~MyItemPainter();

private:
	QSize sizeHint ( const QStyleOptionViewItem & option, const QModelIndex & index ) const;
	void paint ( QPainter * painter, const QStyleOptionViewItem & option, const QModelIndex & index ) const;
	QWidget * createEditor ( QWidget * parent, const QStyleOptionViewItem & option, const QModelIndex & index ) const;
	void setEditorData ( QWidget * editor, const QModelIndex & index ) const;
	void setModelData ( QWidget * editor, QAbstractItemModel * model, const QModelIndex & index ) const;
	void updateEditorGeometry ( QWidget * editor, const QStyleOptionViewItem & option, const QModelIndex & index ) const;
};

#endif // MYITEMPAINTER_H

#include "MyItemPainter.h"
#include <QPainter>
#include <QTextEdit>
#include <QSpinBox>
#include <QFontMetrics>

MyItemPainter::MyItemPainter(QWidget *parent)
	: QStyledItemDelegate(parent)
{

}

MyItemPainter::~MyItemPainter()
{

}

//设置显示的总高度
QSize MyItemPainter::sizeHint ( const QStyleOptionViewItem & option, const QModelIndex & index ) const
{
	//获取每一行的原始大小
	QSize size = QStyledItemDelegate::sizeHint(option,index);
	size.setHeight(60);
	return size;

	//重写之前的默认返回值
	//return QStyledItemDelegate::sizeHint(option,index);
}

void MyItemPainter::paint ( QPainter * painter, const QStyleOptionViewItem & option, const QModelIndex & index ) const
{
	QRect Rect = option.rect;
	Rect.adjust(2,2,-2,-2);

	//取得对应项的数据
	QString strDisplay = index.data(Qt::DisplayRole).toString();//名称
	QString strTip = index.data(Qt::UserRole + 1).toString();//提示
	QString strPath = index.data(Qt::UserRole + 2).toString();//图标路径

	//显示操作:当选中某一项时
	if (option.state & QStyle::State_Selected)
	{
		painter->setBrush(QColor(50,183,183));
		painter->drawRoundedRect(Rect,2,2);
		painter->setBrush(Qt::NoBrush);
	}

	//画名称
	{
		//测量字体的宽度，根据字体实际宽度进行绘制文字，避免显示不全
		QFont font;
		painter->setFont(font);
		QFontMetrics metric(font);
		QRect fontRect = metric.boundingRect(strDisplay);

		QRect dst = Rect;
		dst.setLeft(dst.left()+ 10);
		dst.setRight(dst.left()+fontRect.width());
		dst.setTop(dst.top()+8);
		dst.setBottom(dst.bottom()-40);
		painter->drawText(dst, Qt::AlignLeft | Qt::AlignVCenter, strDisplay);
	}

	//画图标
	{
		QPixmap pmap(strPath);
		QRect dst = Rect;
		dst.setTop(dst.top()+20);
		dst.setRight(dst.left()+40);
		QRect area(0,0,24,24);
		area.moveCenter(dst.center());
		painter->drawPixmap(area,pmap);
	}

	//画提示
	{
		QRect dst = Rect;
		dst.setLeft(dst.left()+45);
		dst.setTop(dst.top()+20);
		painter->drawText(dst, Qt::AlignLeft | Qt::AlignVCenter, strTip);
	}

	//重写之前的默认返回值
	//return QStyledItemDelegate::paint(painter,option,index);
}

//创建一个编辑器返回给视图对象
QWidget * MyItemPainter::createEditor ( QWidget * parent, const QStyleOptionViewItem & option, const QModelIndex & index ) const
{
	QTextEdit* editor = new QTextEdit(parent);
	return editor;
}

//读取要编辑的目标数据项的数据，初始化编辑器
void MyItemPainter::setEditorData ( QWidget * editor, const QModelIndex & index ) const
{
	QString value = index.model()->data(index,Qt::EditRole).toString();
	QTextEdit* testedit = static_cast<QTextEdit*>(editor);
	testedit->setText(value);
}

//读取编辑器中的值，将其写回到目标项中
void MyItemPainter::setModelData ( QWidget * editor, QAbstractItemModel * model, const QModelIndex & index ) const
{
	QTextEdit* testedit = static_cast<QTextEdit*>(editor);
	QString value = testedit->toPlainText();
	model->setData(index,value,Qt::EditRole);
}

//更改数据项的尺寸（外观）
void MyItemPainter::updateEditorGeometry ( QWidget * editor, const QStyleOptionViewItem & option, const QModelIndex & index ) const
{
	editor->setGeometry(option.rect);
}