Qt's custom configuration file class, QSettings application

Table of contents

I. Introduction

During the Qt development process, it is often necessary to add configurations to the software so that the software will retain the settings when it was closed last time when it is opened next time. Qt's configuration class QSettings, this article implements a custom class by inheriting QSettings, which is convenient for calling at any time in the code. In addition, it is set to singleton mode, which is more convenient to use when the program only needs one configuration file.

Two, header file code

config.h

#pragma once
#pragma execution_character_set("utf-8")
#include <QSettings>
#include <QColor>
#include <QVector>
#include <QTextCodec>
class config : public QSettings
{
public:
    ~config();
    config& operator = (const config&) = delete;
    static config &getInstance(void);
    QSettings *configFile;
    void writeConfig(const QString group, const QString key, QVariant value);
    QVariant readConfig(const QString group, const QString key);
    void removeKey(const QString key);
    QStringList readAllKeys(const QString group);        //读取指定结点下的所有键
    QStringList readAllGroups();        //读取所有结点
private:
    config();
    static config * instance;
};

3. Source file code

config.cpp

#include "config.h"
#include <QTextCodec>
config* config::instance = NULL;

config::config()
{
    configFile = new QSettings("./config/configFile.ini",QSettings::IniFormat);
    configFile->setIniCodec(QTextCodec::codecForName("UTF-8"));

    //可以自行添加一些默认配置
    if (configFile->value("Set/length").isNull())
        configFile->setValue("Set/length", 2);
    if (configFile->value("Set/width").isNull())
        configFile->setValue("Set/width", 2.5);
    if (configFile->value("Set/showLog").isNull())
        configFile->setValue("Set/showLog", true);
    if (configFile->value("Net/ip").isNull())
        configFile->setValue("Net/ip", "127.0.0.1");
    if (configFile->value("Net/port").isNull())
        configFile->setValue("Net/port", 8888);

}

config::~config()
{
    delete configFile;
}

config &config::getInstance()
{
    if(instance == NULL)
        instance = new config();
    return *instance;
}

void config::writeConfig(const QString group, const QString key, QVariant value)
{
    QString str("%1/%2");
    configFile->setValue(str.arg(group,key), value);
}

QVariant config::readConfig(const QString group, const QString key)
{
    QString str("%1/%2");
    QVariant qvar = configFile->value(str.arg(group, key));
    return qvar;
}

void config::removeKey(const QString key)
{
    configFile->remove(key);
}

QStringList config::readAllKeys(const QString group)
{
    QStringList result;
    configFile->beginGroup(group);
    result = configFile->childKeys();
    configFile->endGroup();
    return  result;
}

QStringList config::readAllGroups()
{
    return  configFile->childGroups();
}

The configuration file adds some customized default configuration items in the constructor. These configuration items will be added by default when the configuration file is deleted. Modifying the configuration will not affect it.

4. Example of use

#include "common/loger.h"
#include "common/config.h"

int main(int argc, char *argv[])
{
    //读配置
    if (config::getInstance().readConfig("Set", "showLog").toBool()) {
        setLogPath("./" + LOG_FILE_NAME);
        qInstallMessageHandler(customLogMessageHandler);
    }
    //写配置
    config::getInstance().writeConfig("Set", "port", 8877);

    //..........
}

5. Effect of use

After use, the configFile.ini configuration file is generated in the folder.