Qt自定义Combobox实现列表上拉展示

废话

由于最近项目需要，想用一个能够上拉的Combobox,但是试了各种方法发现QCombobox并不能达到我需要的效果，所以决定自己写一个。

方法

其实很简单，combobox可认为是按钮和一个列表组成，按钮由QPushButton来实现，列表由QListView代替。

先来看看效果

![这里写图片描述](http://img.blog.csdn.net/20170609204717828?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvdTAxMDY1NTI4OA==/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast)

代码

.h文件

#ifndef PUSHCOMBOX_H#define PUSHCOMBOX_H#include <QPushButton>#include <QWidget>#include <QListView>#include <qstringlistmodel.h>#include <QModelIndex>class pushcombox : public QPushButton{    Q_OBJECTpublic:    pushcombox(QWidget *widget=0);    Q_PROPERTY(int currentIndex READ currentIndex WRITE setCurrentIndex NOTIFY currentIndexChanged)    Q_PROPERTY(QString currentText READ currentText WRITE setCurrentText NOTIFY currentTextChanged)    void addtextItem(QString );    void addtextItems(QStringList);    int currentIndex(){return  m_currindex;}    QString currentText(){return m_currenttext;}    void setCurrentIndex(int i);    void setCurrentText(QString  str);signals:    void    activated(int index);    void    activated(const QString & text);    void    currentIndexChanged(int index);    void    currentTextChanged(const QString text);public slots:    void    on_clicked();    void    on_showPopup();private:    QListView *listview;    QStringListModel *model;    int m_currindex;    QString m_currenttext;    QWidget *widt;    int parentwith;    int parentheight;};#endif // PUSHCOMBOX_H

.cpp文件

#include "pushcombox.h"#include <QVBoxLayout>#include <QDebug>#include <QDesktopWidget>pushcombox::pushcombox(QWidget *widget) : QPushButton(widget){    m_currindex=0;    m_currenttext="";    widt=new QWidget(widget);    listview=new QListView;    QVBoxLayout *layout=new QVBoxLayout;    layout->addWidget(listview);    layout->setContentsMargins(0,0,0,0);    widt->setLayout(layout);    model=new QStringListModel;    listview->setModel(model);    listview->setEditTriggers(QAbstractItemView::NoEditTriggers);    widt->hide();    connect(listview,SIGNAL(clicked(QModelIndex)),SLOT(on_clicked()));    connect(this,SIGNAL(clicked(bool)),this,SLOT(on_showPopup()));}void pushcombox::addtextItem(QString str){    QStringList list;    list=model->stringList();    list+=str;    model->setStringList(list);    this->setText(list.at(m_currindex));}void pushcombox::on_clicked(){    QStringList list;    list=model->stringList();    this->setText(list.at(listview->currentIndex().row()));    setCurrentIndex(listview->currentIndex().row());    setCurrentText(list.at(listview->currentIndex().row()));    widt->hide();}void pushcombox::on_showPopup(){    if(!widt->isHidden())    {        widt->hide();        return;    }    int height=20*listview->model()->rowCount();    if(height>window()->height()-this->y())        height=this->y();    widt->resize(this->width(),height);    widt->move(this->x(),this->y()-height);    widt->show();}void pushcombox::addtextItems(QStringList list){    model->setStringList(list);    this->setText(list.at(m_currindex));}void pushcombox::setCurrentIndex(int i){    if(i==m_currindex)        return;    m_currindex=i;    QStringList list;    list=model->stringList();    this->setText(list.at(m_currindex));    emit currentIndexChanged(m_currindex);}void pushcombox::setCurrentText(QString str){    if(str==m_currenttext)        return;    m_currenttext=str;    emit currentTextChanged(m_currenttext);}

测试

 pushcombox *com=new pushcombox(this); QStringList list; list<<"1"<<"2"<<"3"<<"4"<<"a"<<"b"<<"c"<<"d"<<"e"<<"f"<<"h"; QStringListModel *model=new QStringListModel; model->setStringList(list); ui->listView->setModel(model); com->addtextItems(list); com->addtextItem("5"); com->addtextItem("6"); connect(com,SIGNAL(currentIndexChanged(int)),this,SLOT(on_mycombobx(int))); connect(com,SIGNAL(currentTextChanged(QString)),this,SLOT(on_mycombobx(QString)));

最后

关于上拉Combobox就这些，其他方向（下拉、侧拉），光标移动时候按钮上文字也跟随光标，控件失去焦点时关闭控件等等由于时间关系没有完善，在这先做个记录希望有时间了会来完成吧！