写在前面

这里自定义一个搜索控件，通过自定义LineEdit的textChange信号，搜索指定内容，并以QCheckBox的方式显示在QListWidget中。

开发版本

Qt: 5.15.2
Qt: Creator10.0.2

编译环境：msvc2019_64bit release

效果

代码

自定义LineEdit，带前缀图标。

//MLineEdit.h
#ifndef MLINEEDIT_H
#define MLINEEDIT_H

#include <QLineEdit>
#include <QHBoxLayout>

class MLineEdit : public QLineEdit
{
    Q_OBJECT
public:
    explicit MLineEdit(QWidget *parent = nullptr);

signals:

private:
    QHBoxLayout* layout;

};

#endif // MLINEEDIT_H

//MLineEdit.cpp
#include "mlineedit.h"
#include <QLabel>
#include <QDebug>

MLineEdit::MLineEdit(QWidget *parent)
    : QLineEdit{parent}
{
    layout = new QHBoxLayout(this);

    QLabel* prefixIcon = new QLabel(this);
    QPixmap pix(":/icons/search.svg");
    prefixIcon->setPixmap(pix);
    prefixIcon->setFixedSize(pix.size());

    layout->addWidget(prefixIcon);
    layout->setContentsMargins(1, 1, 1, 1);
    layout->addStretch();
    layout->setDirection(QBoxLayout::LeftToRight);

    qDebug() << font();

    setFont(QFont("SimSun", 15));

    setTextMargins(prefixIcon->width(), 1, 1, 1);

    QString qss = QString("QLineEdit{border:1px solid gray;border-radius:10px;}");
    setStyleSheet(qss);
}

应用实现：

//MyWidgets.h
#ifndef MYWIDGETS_H
#define MYWIDGETS_H

#include <QWidget>

QT_BEGIN_NAMESPACE
namespace Ui { class MyWidgets; }
QT_END_NAMESPACE

class MyWidgets : public QWidget
{
    Q_OBJECT

public:
    MyWidgets(QWidget *parent = nullptr);
    ~MyWidgets();

public slots:
    void textChangeSlot(const QString& text);

private:
    Ui::MyWidgets *ui;

    QStringList qlCheck;
};
#endif // MYWIDGETS_H

//MyWidgets.cpp
#include "mywidgets.h"
#include "ui_mywidgets.h"

#include <QPushButton>
#include <QIcon>
#include <QCheckBox>
#include <QDebug>
#include <QListWidgetItem>
#include "mlineedit.h"

MyWidgets::MyWidgets(QWidget *parent)
    : QWidget(parent)
    , ui(new Ui::MyWidgets)
{
    ui->setupUi(this);
    
    qlCheck << tr("whatsApp") << tr("weChat") << tr("QQ") << tr("Telegram") << tr("twitter");
    connect(ui->lineEdit, &QLineEdit::textChanged, this, &MyWidgets::textChangeSlot);
}

MyWidgets::~MyWidgets()
{
    delete ui;
}

void MyWidgets::textChangeSlot(const QString& text)
{
    QString qsInput = ui->lineEdit->text();

    qDebug() << qsInput;

    ui->listWidget->clear();

    if (qsInput.isEmpty())
    {
        return;
    }

    for (QString qs : qlCheck)
    {
        if (qs.contains(qsInput, Qt::CaseInsensitive))
        {
            QCheckBox* checkBox = new QCheckBox(this);
            checkBox->setText(qs);

            QListWidgetItem* listItem = new QListWidgetItem();
            ui->listWidget->addItem(listItem);
            ui->listWidget->setItemWidget(listItem, checkBox);
        }
    }
}