Qt浅谈之四十七下拉列表菜单
本文共 17905 字，大约阅读时间需要 59 分钟。
一、简介
在QGraphicsItem下使用QListWidget实现下拉列表的功能，并显示所有的选项，便于浏览和查询数据。
二、详解
1、部分代码
（1）clusterlistwidget.h
#ifndef CLUSTERLISTWIDGET_H#define CLUSTERLISTWIDGET_H#include#include #include "custombtn.h"#include "pagenumbercontrol.h"class SearchLineEdit;enum TYPE{cluster=0,host,vm};class ClusterListWidget : public QWidget{ Q_OBJECTpublic: explicit ClusterListWidget(TYPE type = cluster,QWidget *parent = 0); void setListWidget(); void setTitle(QString title); void listInit();signals:public slots: void textChange(QString text); void pageChange(int currentnumber); void editClicked(); void btnClicked(); void itemEnteredSlot(QListWidgetItem * i); void itemClickedSlot(QListWidgetItem * i); void rowChanged(int row);protected: //bool eventFilter(QObject * obj, QEvent *e); void paintEvent(QPaintEvent *e); void showEvent(QShowEvent *e); void keyPressEvent(QKeyEvent *e);private: void setImgs(const QString &normal,const QString &abnormal,const QString &error); void setVmImgs(const QString &linux_normal,const QString &linux_abnormal,const QString &linux_error,const QString &linux_off, const QString &windows_normal,const QString &windows_abnormal,const QString &windows_error,const QString &windows_off);private: //QString _icon; QPixmap backGroundPix; QStringList NameList; QStringList _searchList; QStringList _list; QLabel *lb1; QLabel *lb2; PageNumberControl *_page; int _maxNum; int _currentNum; int _searchNUm; SearchLineEdit *_searchLineEdit; QListWidget * _cluster; QPushButton *_btn; int _n;//记录键盘 上下见 int _x; int _y; QPixmap _enterPixmap; bool _enter; QString _title; QString _normal; QString _abnormal; QString __error; TYPE _type; QString _linux_normal; QString _linux_abnormal; QString _linux_error; QString _linux_off; QString _windows_normal; QString _windows_abnormal; QString _windows_error; QString _windows_off;};class SearchLineEdit : public QLineEdit{ Q_OBJECT public: explicit SearchLineEdit(QWidget *parent = 0); signals: void pressed(); protected: void focusInEvent(QFocusEvent *e); void focusOutEvent(QFocusEvent *e); private:};#endif // CLUSTERLISTWIDGET_H
（2）clusterlistwidget.cpp
#include "clusterlistwidget.h"ClusterListWidget::ClusterListWidget(TYPE type,QWidget *parent) : QWidget(parent,Qt::FramelessWindowHint) ,_maxNum(0) ,_searchNUm(0) ,_n(-1) ,_x(0) ,_y(0) ,_enter(false){ NameList<<"a"<<"b"<<"c"<<"d"<<"e"<<"a"<<"b"<<"c"<<"d"<<"e" <<"a"<<"b"<<"c"<<"d"<<"e"<<"a"<<"b"<<"c"<<"d"<<"e" <<"a"<<"b"<<"c"<<"d"<<"e"<<"a"<<"b"<<"c"<<"d"<<"e" <<"a"<<"b"<<"c"<<"d"<<"e"<<"a"<<"b"<<"c"<<"d"<<"e"<<"hjhjha"; backGroundPix = QPixmap(":/images/handleMenu_bg.png"); resize(backGroundPix.width(), backGroundPix.height()); qDebug()< < setPixmap(QPixmap(":/images/handleMenu_allClusters.png")); lb1->move(10,12); lb2 = new QLabel(this); lb2->move(33,12); lb2->setStyleSheet("color:#b4e5fd"); _page = new PageNumberControl(this); _page->setCluster(true); _maxNum = (_list.count() - 1) / 16 +1; _currentNum = 1; _page->setTotalPage(_maxNum); _page->move(145,12); _searchLineEdit = new SearchLineEdit(this);// _searchLineEdit->setImgs(":/images/handleMenu_searchInput.png",":/images/handleMenu_searchInput_click.png",// ":/images/handleMenu_searchInput.png",":/images/handleMenu_searchInput.png"); _searchLineEdit->setStyleSheet("background-image:url(:/images/handleMenu_searchInput.png);border:1px solid #536874;"); _searchLineEdit->move(8,38); _searchLineEdit->resize(168,23); _searchLineEdit->installEventFilter(this); //_searchLineEdit->setFocusPolicy(Qt::NoFocus); _btn = new QPushButton(this); _btn->resize(14,14); _btn->move(155,41); _btn->setStyleSheet("QPushButton{background-color:transparent;border:0px;}"); _btn->setFocusPolicy(Qt::NoFocus); _btn->setVisible(false); connect(_btn,SIGNAL(clicked()),this,SLOT(btnClicked())); _cluster = new QListWidget(this); _cluster->show(); setListWidget(); _cluster->setMouseTracking(true); _cluster->setFocusPolicy(Qt::NoFocus); //_cluster->installEventFilter(this); connect(_searchLineEdit,SIGNAL(textChanged(QString)),this,SLOT(textChange(QString))); connect(_page,SIGNAL(currentPageChanged(int)),this,SLOT(pageChange(int))); connect(_searchLineEdit,SIGNAL(pressed()),this,SLOT(editClicked())); connect(_cluster,SIGNAL(itemEntered(QListWidgetItem*)),this,SLOT(itemEnteredSlot(QListWidgetItem*))); connect(_cluster,SIGNAL(itemClicked(QListWidgetItem*)),this,SLOT(itemClickedSlot(QListWidgetItem*))); connect(_cluster,SIGNAL(currentRowChanged(int)),this,SLOT(rowChanged(int))); //this->setFocus(); //this->installEventFilter(this);}void ClusterListWidget::setListWidget(){ _cluster->setStyleSheet("QListWidget{background-color:transparent;color:#19649F;border:0px solid gray;}" "QListWidget::item{background-color:transparent;border:0px solid gray;padding-left:28px;color:#b4e5fd}" //"QListWidget::item:!selected{border:0px solid gray;padding-left:28px;color:#b4e5fd}" //"QListWidget::item:selected:active{background-image:url(:/images/handleMenu_lixt_bg_selected.png);color:#b4e5fd;border-width:0;}" "QListWidget::item:selected{background-image:url(:/images/handleMenu_lixt_bg_selected.png);}" ); _cluster->move(0,62); _cluster->resize(183,540); _cluster->clear(); pageChange(1);}void ClusterListWidget::setTitle(QString title){ lb2->setText(title);}void ClusterListWidget::setImgs(const QString &normal, const QString &abnormal, const QString &error){ _normal = normal; _abnormal = abnormal; __error = error;}void ClusterListWidget::setVmImgs(const QString &linux_normal, const QString &linux_abnormal, const QString &linux_error, const QString &linux_off, const QString &windows_normal, const QString &windows_abnormal, const QString &windows_error, const QString &windows_off){ _linux_normal = linux_normal; _linux_abnormal = linux_abnormal; _linux_error = linux_error; _linux_off = linux_off; _windows_normal = windows_normal; _windows_abnormal = windows_abnormal; _windows_error = windows_error; _windows_off = windows_off;}void ClusterListWidget::editClicked(){ _searchLineEdit->setStyleSheet("background-image:url(:/images/handleMenu_searchInput_click.png);border:1px solid #536874;"); _searchLineEdit->update(); _btn->setVisible(true);}void ClusterListWidget::btnClicked(){ _searchLineEdit->clear(); _searchLineEdit->setStyleSheet("background-image:url(:/images/handleMenu_searchInput.png);border:1px solid #536874;"); this->setFocus();}void ClusterListWidget::itemEnteredSlot(QListWidgetItem *i){ _n = _cluster->row(i); if(_n == _cluster->currentRow()) { _enter = false; }else{ _enter = true;} _x = 0; _y = _cluster->row(i)*33 +62; _enterPixmap = QPixmap(":/images/handleMenu_lixt_bg_hover.png"); _cluster->update();}void ClusterListWidget::itemClickedSlot(QListWidgetItem *i){ int row =_cluster->row(i); qDebug()<< (_currentNum -1)*16 + row; _enter = false;//选中跟悬停 只显示选中背景图片 _cluster->update();}void ClusterListWidget::rowChanged(int row){ //qDebug()<< (_currentNum -1)*16 + row; _enter = false;//选中跟悬停 只显示选中背景图片 _cluster->update(); _n = row;}//bool ClusterListWidget::eventFilter(QObject *obj, QEvent *e)//{// if(obj == _cluster){// if(e->type() == QEvent::Leave)// {// _enter = false;// _cluster->update();// _n = _cluster->currentRow();// return true;// }// }// return false;// QWidget::eventFilter(obj,e);//}void ClusterListWidget::textChange(QString text){ _cluster->clear(); _list.clear(); _searchList.clear(); for(int i = 0;i < NameList.count();i++){ if(NameList.at(i).contains(text)) { _searchList.append(NameList.at(i)); } } _list = _searchList; _maxNum = (_list.count() - 1) / 16 +1; _currentNum = 1; _page->setTotalPage(_maxNum); pageChange(1); _cluster->update();}void ClusterListWidget::pageChange(int currentnumber){ _currentNum = currentnumber; _cluster->clear(); switch (_type) { case 0: setTitle(tr("all cluster")); setImgs(":/images/handleMenu_clusters.png", ":/images/handleMenu_clusters_abnormal.png",":/images/handleMenu_clusters_error.png"); if(_currentNum != _maxNum) { for(int i= (_currentNum -1) * 16;i <(_currentNum) * 16 ;i++ ) { QListWidgetItem *item = new QListWidgetItem; item->setSizeHint(QSize(183,33)); item->setText(" "+_list.at(i)); item->setIcon(QIcon(_normal)); _cluster->addItem(item); } }else{ for(int i = (_currentNum -1) * 16;i < _list.count();i++) { QListWidgetItem *item = new QListWidgetItem; item->setSizeHint(QSize(183,33)); item->setText(" "+_list.at(i)); item->setIcon(QIcon(__error)); _cluster->addItem(item); } } break; case 1: setImgs(":/images/handleMenu_host.png", ":/images/handleMenu_host_abnormal.png",":/images/handleMenu_host_error.png"); if(_currentNum != _maxNum) { for(int i= (_currentNum -1) * 16;i <(_currentNum) * 16 ;i++ ) { QListWidgetItem *item = new QListWidgetItem; item->setSizeHint(QSize(183,33)); item->setText(" "+_list.at(i)); item->setIcon(QIcon(_abnormal)); _cluster->addItem(item); } }else{ for(int i = (_currentNum -1) * 16;i < _list.count();i++) { QListWidgetItem *item = new QListWidgetItem; item->setSizeHint(QSize(183,33)); item->setText(" "+_list.at(i)); item->setIcon(QIcon(__error)); _cluster->addItem(item); } } break; case 2: setVmImgs(":/images/handleMenu_vm.png",":/images/handleMenu_vm_linux_abnormal.png",":/images/handleMenu_vm_linux_error.png", ":/images/handleMenu_vm_linux_shutdown.png",":/images/handleMenu_vm_windows.png",":/images/handleMenu_vm_windows_abnormal.png", ":/images/handleMenu_vm_windows_error.png",":/images/handleMenu_vm_windows_shutdown.png"); if(_currentNum != _maxNum) { for(int i= (_currentNum -1) * 16;i <(_currentNum) * 16 ;i++ ) { QListWidgetItem *item = new QListWidgetItem; item->setSizeHint(QSize(183,33)); item->setText(" "+_list.at(i)); item->setIcon(QIcon(_linux_abnormal)); _cluster->addItem(item); } }else{ for(int i = (_currentNum -1) * 16;i < _list.count();i++) { QListWidgetItem *item = new QListWidgetItem; item->setSizeHint(QSize(183,33)); item->setText(" "+_list.at(i)); item->setIcon(QIcon(_windows_error)); _cluster->addItem(item); } } break; default: break; } _cluster->setCurrentRow(0);}void ClusterListWidget::paintEvent(QPaintEvent *e){ QPainter painter(this); painter.drawPixmap(0, 0, backGroundPix.width(), backGroundPix.height(), backGroundPix); if(_enter) { painter.drawPixmap(_x,_y,183,33,_enterPixmap); } //painter.setPen(QColor("#b4e5fd"));}void ClusterListWidget::showEvent(QShowEvent *e){ setListWidget();}void ClusterListWidget::keyPressEvent(QKeyEvent *e){ qDebug()<<"aaaaaaaaaaaaaaaaaaaaaa"<<_n; //n = _cluster->currentRow(); if(e->key() == Qt::Key_Up) { if(_n > 0) { _n -= 1; } itemEnteredSlot(_cluster->item(_n)); //_cluster->setCurrentRow(n); return; } if(e->key() == Qt::Key_Down) { if( _n < _cluster->count() -1){ _n += 1; itemEnteredSlot(_cluster->item(_n)); } //_cluster->setCurrentRow(n); return; } if(e->key() == Qt::Key_Enter || e->key() == Qt::Key_Return) { qDebug()<<"777777777777777"; _cluster->setCurrentRow(_n); return; } QWidget::keyPressEvent(e);}SearchLineEdit::SearchLineEdit(QWidget *parent) :QLineEdit(parent){}void SearchLineEdit::focusInEvent(QFocusEvent *e){ emit pressed(); QLineEdit::focusInEvent(e);}void SearchLineEdit::focusOutEvent(QFocusEvent *e){ QLineEdit::focusInEvent(e);} （3）clusterlistitem.h
#ifndef CLUSTERLISTITEM_H#define CLUSTERLISTITEM_H#include#include "graphicsitembutton.h"#include "clusterlistwidget.h"#include #include class clusterListItem : public QObject, public QGraphicsItem{ Q_OBJECTpublic: explicit clusterListItem(QGraphicsItem *parent = 0); QRectF boundingRect() const;signals:protected: void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget); bool eventFilter(QObject *obj, QEvent *event);private slots: void slotBtnClicked();private: int _width; int _height; GraphicsItemButton * _listBtn; ClusterListWidget * _clusterWidget; QGraphicsProxyWidget *_proxy; bool _show; bool _focus;};#endif // CLUSTERLISTITEM_H
（4）clusterlistitem.cpp
#include "clusterlistitem.h"clusterListItem::clusterListItem(QGraphicsItem *parent) : QGraphicsItem(parent) ,_show(false){ setFiltersChildEvents(true); //setAcceptedMouseButtons(Qt::LeftButton); //setAcceptHoverEvents(true); _width = 22; _height =21; _listBtn = new GraphicsItemButton(":/images/handleMenu_icon.png", ":/images/handleMenu_icon_hover.png", ":/images/handleMenu_icon_hover.png", "", GraphicsItemButton::normal,this); _listBtn->setSize(22,21); _listBtn->setPos(0,0); _listBtn->installEventFilter(this); _clusterWidget = new ClusterListWidget(cluster); _proxy = new QGraphicsProxyWidget(this); _proxy->setWidget(_clusterWidget); _proxy->setPos(0,21); _proxy->setVisible(_show); _clusterWidget->installEventFilter(this); //this->installEventFilter(this); connect(_listBtn,SIGNAL(clicked()),this,SLOT(slotBtnClicked()));}QRectF clusterListItem::boundingRect() const{ return QRectF(0, 0, _width, _height);}void clusterListItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget){ //painter->fillRect(QRectF(0, 0, _width, _height), QColor("#FF0000"));}bool clusterListItem::eventFilter(QObject *obj, QEvent *event){ if (event->type() == QEvent::FocusIn) { qDebug() << "QEvent::FocusIn---" << obj; } if (event->type() == QEvent::FocusOut) { qDebug() << "QEvent::FocusOut---" << obj; } if (event->type() == QEvent::MouseButtonPress) { qDebug() << obj; if (obj == _clusterWidget) { return true; } else { if (_show == true) { _listBtn->setCurrent(false); _show = false; //_clusterWidget->hide(); QPropertyAnimation *animation = new QPropertyAnimation(_clusterWidget, "geometry"); animation->setDuration(300); animation->setStartValue(QRect(0,21,183,602)); animation->setEndValue(QRect(0,21,183,0)); animation->start(); } } } return QObject::eventFilter(obj, event);}void clusterListItem::slotBtnClicked(){ this->setFocus(); _listBtn->setCurrent(true); if(!_show){ //_proxy->setVisible(!_show); _proxy->show(); QPropertyAnimation *animation = new QPropertyAnimation(_clusterWidget, "geometry"); animation->setDuration(300); animation->setStartValue(QRect(0,21,183,0)); animation->setEndValue(QRect(0,21,183,602)); animation->start(); _show = true; } else{ QPropertyAnimation *animation = new QPropertyAnimation(_clusterWidget, "geometry"); animation->setDuration(300); animation->setStartValue(QRect(0,21,183,602)); animation->setEndValue(QRect(0,21,183,0)); animation->start(); _show = false; }} （5）main.cpp
#include "clusterlistwidget.h"#include#include #include #include "clusterlistitem.h"int main(int argc, char *argv[]){ QApplication a(argc, argv); QTextCodec::setCodecForTr(QTextCodec::codecForLocale()); QGraphicsView view; //view.resize(300,800); QGraphicsScene scene; scene.setSceneRect(-100, -300, 200, 600); view.setScene(&scene); view.setSceneRect(0, 0, 200, 600); //view.setCacheMode(QGraphicsView::CacheBackground); //view.setViewportUpdateMode(QGraphicsView::BoundingRectViewportUpdate); clusterListItem *item = new clusterListItem; scene.addItem(item); item->setPos(0, 0); view.resize(314, 814); view.show(); view.installEventFilter(item); return a.exec();}
三、总结
（1）可以在eventFilter的QEvent::FocusIn和QEvent::FocusOut增加当鼠标移出菜单后自动回收的功能。其他的功能还需进一步完善。
（2）若有问题或建议，请留言，在此感谢！
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