QComboBox下拉列表的宽度自适应

参考资料：https://blog.csdn.net/qq_31073871/article/details/79851430

comboboxex.h

#ifndef COMBOBOXEX_H
#define COMBOBOXEX_H
#include <QWidget>
#include<QComboBox>
class ComboBoxEx : public QComboBox
{
    Q_OBJECT
public:
    explicit ComboBoxEx(QWidget *parent = nullptr);
    void adjustItemWidth();
signals:
public slots:
};
#endif // COMBOBOXEX_H

comboboxex.c

#include "comboboxex.h"
#include<QAbstractItemView>
ComboBoxEx::ComboBoxEx(QWidget *parent):
    QComboBox(parent)
{
}
void ComboBoxEx::adjustItemWidth()
{
    int max_len=0;
    for(int idx=0;idx < this->count();idx++)
    {
        if(max_len < this->itemText(idx).length())
            max_len = this->itemText(idx).length();
    }
    int pt_val = this->font().pointSize();//获取字体的磅值
    this->view()->setFixedWidth(max_len*pt_val*0.75);//（字符数*每个字符的宽度(磅)*0.75）个像素
}

mainwindow.c

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "commonfunction.h"
#include "comboboxex.h"
#include <QDebug>
#include <QSerialPortInfo>
#define debug qDebug() << "[" << __FILE__ << ":" << __LINE__ << "]" // 调试
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    // 智能识别当前系统的有效串口号
    QList<QSerialPortInfo> serialPortInfo = QSerialPortInfo::availablePorts();
    int count = serialPortInfo.count();
    for(int i = 0; i<count; i++)
    {
        // serialPortInfo.at(i).portName() 获取端口号
        // serialPortInfo.at(i).description() 获取端口号描述
        QString comStr = QString("%1 %2").arg(serialPortInfo.at(i).portName())
                                        .arg(serialPortInfo.at(i).description());
        ui->comPortName->addItem(comStr);
        debug << serialPortInfo.at(i).description();
    }
    ui->comPortName->adjustItemWidth(); // 设置下拉框的宽度跟随内容变化
}
MainWindow::~MainWindow()
{
    delete ui;
}
......

将端口号的下拉框提升为自定义的ComboBoxEx类

comboboxex.h
comboboxex.cpp
DevConfig.zip