QT 笔记

2024-08-04

本文作者原创，首发在本博客；CSDN 上的同名文章已标注为转载并回链到本页：https://blog.csdn.net/qq_30220519/article/details/140909372

HTTPS SSL配置
- 下载
- 配置
子父对象

QTimer *timer = new QTimer;         // QTimer inherits QObject
timer->inherits("QTimer");          // returns true
timer->inherits("QObject");         // returns true
timer->inherits("QAbstractButton"); // returns false

文件权限

extern Q_CORE_EXPORT int qt_ntfs_permission_lookup;
qt_ntfs_permission_lookup++; // turn checking on
qt_ntfs_permission_lookup--; // turn it off again

QFile::Permissions pers;    

QFile file("D:/DOWN/f.txt");  

file.open(QFile::ReadOnly);    

pers =file.permissions();    

qDebug() <<pers;  

file.setPermissions(QFile::ReadOwner);    

qDebug() <<file.permissions();    

file.setPermissions(pers);

QMediaPlayer本地解码器

WIN上下载k-lite或者LAV Filters安装即可。

// 创建实例 
QObjectCleanupHandler *cleaner = new QObjectCleanupHandler; 
// 创建窗口 
QPushButton *w = new QPushButton("Remove Me"); 
w->show(); 
// 注册第一个按钮 
cleaner->add(w); 
// 如果第一个按钮点击之后，删除自身 
connect(w, SIGNAL(clicked()), w, SLOT(deleteLater())); 
// 创建第二个按钮，注意，这个按钮没有任何动作 
w = new QPushButton("Nothing"); 
cleaner->add(w); 
w->show(); 
// 创建第三个按钮，删除所有 
w = new QPushButton("Remove All"); 
cleaner->add(w); 
connect(w, SIGNAL(clicked()), cleaner, SLOT(deleteLater())); 
w->show();

弱指针

// QPointer 表现类似普通指针 
QDate *mydate = new QDate(QDate::currentDate()); 
QPointer mypointer = mydata; 
mydate->year();    // -> 2005 
mypointer->year(); // -> 2005 
  
// 当对象 delete 之后，QPointer 会有不同的表现 
delete mydate; 
  
if(mydate == NULL) 
    printf("clean pointer"); 
else 
    printf("dangling pointer"); 
// 输出 dangling pointer 
  
if(mypointer.isNull()) 
    printf("clean pointer"); 
else 
    printf("dangling pointer"); 
// 输出 clean pointer

内置图标

1	QStyle::SP_TitleBarMenuButton

pro文件解析

宏定义

QScroller

1 2	ui->listWidget->setHorizontalScrollMode(QListWidget::ScrollPerPixel); QScroller::grabGesture(ui->listWidget,QScroller::LeftMouseButtonGesture);

代码重构
QtCreator软件的配置文件

C:\Users\Administrator\AppData\Roaming\QtProject

QtCreator UI
守护进程


/*为了使得兼容任意程序，特意提炼出来共性，增加了多种设置。

可设置检测的程序名称。

可设置udp通信端口。

可设置超时次数。

自动记录已重启次数。

自动记录最后一次重启时间。

是否需要重新刷新桌面。

可重置当前重启次数和最后重启时间。

自动隐藏的托盘运行或者后台运行。

提供界面设置程序名称已经开启和暂停服务。*/

1#pragma execution_character_set("utf-8")
2#include "frmmain.h"
3#include "ui_frmmain.h"
4#include "qtimer.h"
5#include "qudpsocket.h"
6#include "qsharedmemory.h"
7#include "qprocess.h"
8#include "qdatetime.h"
9#include "qapplication.h"
10#include "qdesktopservices.h"
11#include "qmessagebox.h"
12#if (QT_VERSION > QT_VERSION_CHECK(5,0,0))
13#include "qstandardpaths.h"
14#endif
15
16#include "app.h"
17
18frmMain::frmMain(QWidget *parent) : QWidget(parent), ui(new Ui::frmMain)
19{
20    ui->setupUi(this);
21    this->initForm();
22}
23
24frmMain::~frmMain()
25{
26    delete ui;
27}
28
29void frmMain::changeEvent(QEvent *event)
30{
31    //隐藏当前界面,最小化到托盘
32    if(event->type() == QEvent::WindowStateChange) {
33        if(windowState() & Qt::WindowMinimized) {
34            hide();
35        }
36    }
37
38    QWidget::changeEvent(event);
39}
40
41void frmMain::initForm()
42{
43    count = 0;
44    ok = false;
45
46    //每秒钟定时询问心跳
47    timerHeart = new QTimer(this);
48    timerHeart->setInterval(2000);
49    connect(timerHeart, SIGNAL(timeout()), this, SLOT(sendHearData()));
50
51    //从6050端口开始,如果绑定失败则将端口加1,直到绑定成功
52    udp = new QUdpSocket(this);
53    int port = 6050;
54    while(!udp->bind(port)) {
55        port++;
56    }
57
58    connect(udp, SIGNAL(readyRead()), this, SLOT(readData()));
59
60    if (App::TargetAppName.isEmpty()) {
61        ui->btnStart->setText("启动");
62        ui->btnStart->setEnabled(false);
63        timerHeart->stop();
64    } else {
65        ui->btnStart->setText("暂停");
66        ui->btnStart->setEnabled(true);
67        timerHeart->start();
68    }
69
70    ui->txtAppName->setText(App::TargetAppName);
71    ui->txtAppName->setFocus();
72}
73
74void frmMain::sendHearData()
75{
76    udp->writeDatagram("hello", QHostAddress::LocalHost, App::TargetAppPort);
77
78    //判断当前是否没有回复
79    if (!ok) {
80        count++;
81    } else {
82        count = 0;
83        ok = false;
84    }
85
86    //如果超过规定次数没有收到心跳回复,则超时重启
87    if (count >= App::TimeoutCount) {
88        timerHeart->stop();
89
90        QSharedMemory mem(App::TargetAppName);
91        if (!mem.create(1)) {
92            killApp();
93        }
94
95        QTimer::singleShot(1000 , this, SLOT(killOther()));
96        QTimer::singleShot(3000 , this, SLOT(startApp()));
97        QTimer::singleShot(4000 , this, SLOT(startExplorer()));
98    }
99}
100
101void frmMain::killApp()
102{
103    QProcess *p = new QProcess;
104    p->start(QString("taskkill /im %1.exe /f").arg(App::TargetAppName));
105}
106
107void frmMain::killOther()
108{
109    QProcess *p = new QProcess;
110    p->start(QString("taskkill /im %1.exe /f").arg("WerFault"));
111
112    //重建缓存,彻底清除托盘图标
113    if (App::ReStartExplorer) {
114        QProcess *p1 = new QProcess;
115        p1->start("taskkill /f /im explorer.exe");
116    }
117}
118
119void frmMain::startApp()
120{
121    if (ui->btnStart->text() == "开始" || ui->btnStart->text() == "启动") {
122        count = 0;
123        return;
124    }
125
126    QProcess *p = new QProcess;
127    p->start(QString(""%1/%2.exe"").arg(qApp->applicationDirPath()).arg(App::TargetAppName));
128
129    count = 0;
130    ok = true;
131    timerHeart->start();
132
133    App::ReStartCount++;
134    App::ReStartLastTime = QDateTime::currentDateTime().toString("yyyy-MM-dd HH:mm:ss");
135    App::writeConfig();
136
137    ui->labCount->setText(QString("已重启 %1 次").arg(App::ReStartCount));
138    ui->labInfo->setText(QString("最后一次重启在 %1").arg(App::ReStartLastTime));
139}
140
141void frmMain::startExplorer()
142{
143    //取得操作系统目录路径,指定操作系统目录下的explorer程序,采用绝对路径,否则在64位操作系统下无效
144#if (QT_VERSION > QT_VERSION_CHECK(5,0,0))
145    QString str = QStandardPaths::writableLocation(QStandardPaths::ApplicationsLocation);
146#else
147    QString str = QDesktopServices::storageLocation(QDesktopServices::ApplicationsLocation);
148#endif
149
150    if (App::ReStartExplorer) {
151        str = QString("%1\\Windows\\explorer.exe").arg(str.mid(0, 2));
152        QProcess *p = new QProcess(this);
153        p->start(str);
154    }
155}
156
157void frmMain::readData()
158{
159    QByteArray tempData;
160    do {
161        tempData.resize(udp->pendingDatagramSize());
162        udp->readDatagram(tempData.data(), tempData.size());
163        QString data = QLatin1String(tempData);
164        if (data.right(2) == "OK") {
165            count = 0;
166            ok = true;
167        }
168    } while (udp->hasPendingDatagrams());
169}
170
171void frmMain::on_btnOk_clicked()
172{
173    App::TargetAppName = ui->txtAppName->text();
174    if (App::TargetAppName == "") {
175        QMessageBox::critical(this, "提示", "应用程序名称不能为空!");
176        ui->txtAppName->setFocus();
177        return;
178    }
179
180    App::writeConfig();
181    ui->btnStart->setEnabled(true);
182}
183
184void frmMain::on_btnStart_clicked()
185{
186    count = 0;
187    if (ui->btnStart->text() == "暂停") {
188        timerHeart->stop();
189        ui->btnStart->setText("开始");
190    } else {
191        timerHeart->start();
192        ui->btnStart->setText("暂停");
193    }
194}
195
196void frmMain::on_btnReset_clicked()
197{
198    App::ReStartCount = 0;
199    App::ReStartLastTime = "2019-01-01 12:00:00";
200    App::writeConfig();
201
202    ui->txtAppName->setText(App::TargetAppName);
203    ui->labCount->setText(QString("已重启 %1 次").arg(App::ReStartCount));
204    ui->labInfo->setText(QString("最后一次重启在 %1").arg(App::ReStartLastTime));
205    QMessageBox::information(this, "提示", "重置配置文件成功!");
206}
主程序使用核心代码：
1#include "applive.h"
2#include "qmutex.h"
3#include "qudpsocket.h"
4#include "qstringlist.h"
5#include "qapplication.h"
6#include "qdatetime.h"
7#include "qdebug.h"
8
9#define TIMEMS qPrintable(QTime::currentTime().toString("HH:mm:ss zzz"))
10
11QScopedPointer<AppLive> AppLive::self;
12AppLive *AppLive::Instance()
13{
14    if (self.isNull()) {
15        QMutex mutex;
16        QMutexLocker locker(&mutex);
17        if (self.isNull()) {
18            self.reset(new AppLive);
19        }
20    }
21
22    return self.data();
23}
24
25AppLive::AppLive(QObject *parent) : QObject(parent)
26{
27    udpServer  = new QUdpSocket(this);
28
29    QString name = qApp->applicationFilePath();
30    QStringList list = name.split("/");
31    appName = list.at(list.count() - 1).split(".").at(0);
32}
33
34void AppLive::readData()
35{
36    QByteArray tempData;
37
38    do {
39        tempData.resize(udpServer->pendingDatagramSize());
40        QHostAddress sender;
41        quint16 senderPort;
42        udpServer->readDatagram(tempData.data(), tempData.size(), &sender, &senderPort);
43        QString data = QLatin1String(tempData);
44
45        if (data == "hello") {
46            udpServer->writeDatagram(QString("%1OK").arg(appName).toLatin1(), sender, senderPort);
47        }
48    } while (udpServer->hasPendingDatagrams());
49}
50
51bool AppLive::start(int port)
52{
53    bool ok = udpServer->bind(port);
54    if (ok) {
55        connect(udpServer, SIGNAL(readyRead()), this, SLOT(readData()));
56        qDebug() << TIMEMS << "Start AppLive Ok";
57    }
58
59    return ok;
60}
61
62void AppLive::stop()
63{
64    udpServer->abort();
65    disconnect(udpServer, SIGNAL(readyRead()), this, SLOT(readData()));
66}

Qt密钥生成器


在很多商业软件中，需要提供一些可以试运行的版本，这样就需要配套密钥机制来控制，纵观大部分的试用版软件，基本上采用以下几种机制来控制。


远程联网激活，每次启动都联网查看使用时间等，这种方法最完美，缺点是没法联网的设备就歇菜了。

通过获取本地的硬盘+CPU等硬件的编号，做一个运算，生成一个激活码，超过半数的软件会采用此方法，缺点是不能自由控制软件的其他参数，比如软件中添加的设备数量的控制。

设定一个运行到期时间+数量限制+已运行时间的密钥文件，发给用户配套软件使用，缺点是如果仅仅设置的是运行到期时间，用户可以更改电脑时间来获取更长的使用时间，在电脑不联网的情况下。

本demo采用抛砖引玉的形式，用第三种方法来实现，密钥文件采用最简单的异或加密，可以自行改成其他加密方法。
核心代码：
1#include "frmmain.h"
2#include "ui_frmmain.h"
3#include "qmessagebox.h"
4#include "qfile.h"
5
6frmMain::frmMain(QWidget *parent) : QWidget(parent), ui(new Ui::frmMain)
7{
8    ui->setupUi(this);
9    this->initForm();
10}
11
12frmMain::~frmMain()
13{
14    delete ui;
15}
16
17void frmMain::initForm()
18{
19    QStringList min;
20    min << "1" << "5" << "10" << "20" << "30";
21    for (int i = 1; i <= 24; i++) {
22        min << QString::number(i * 60);
23    }
24
25    ui->cboxMin->addItems(min);
26    ui->cboxMin->setCurrentIndex(1);
27    ui->dateEdit->setDate(QDate::currentDate());
28
29    for (int i = 5; i <= 150; i = i + 5) {
30        ui->cboxCount->addItem(QString("%1").arg(i));
31    }
32}
33
34QString frmMain::getXorEncryptDecrypt(const QString &data, char key)
35{
36    //采用异或加密,也可以自行更改算法
37    QByteArray buffer = data.toLatin1();
38    int size = buffer.size();
39    for (int i = 0; i < size; i++) {
40        buffer[i] = buffer.at(i) ^ key;
41    }
42
43    return QLatin1String(buffer);
44}
45
46void frmMain::on_btnOk_clicked()
47{
48    bool useDate = ui->ckDate->isChecked();
49    bool useRun = ui->ckRun->isChecked();
50    bool useCount = ui->ckCount->isChecked();
51
52    if (!useDate && !useRun && !useCount) {
53        if (QMessageBox::question(this, "询问", "确定要生成没有任何限制的密钥吗?") != QMessageBox::Yes) {
54            return;
55        }
56    }
57
58    QString strDate = ui->dateEdit->date().toString("yyyy-MM-dd");
59    QString strRun = ui->cboxMin->currentText();
60    QString strCount = ui->cboxCount->currentText();
61    QString key = QString("%1|%2|%3|%4|%5|%6").arg(useDate).arg(strDate).arg(useRun).arg(strRun).arg(useCount).arg(strCount);
62
63    QFile file(QApplication::applicationDirPath() + "/key.db");
64    file.open(QFile::WriteOnly | QIODevice::Text);
65    file.write(getXorEncryptDecrypt(key, 110).toLatin1());
66    file.close();
67    QMessageBox::information(this, "提示", "生成密钥成功,将 key.db 文件拷贝到对应目录即可!");
68}
69
70void frmMain::on_btnClose_clicked()
71{
72    this->close();
73}

MiniDump
扩展库
获取硬件信息

QString frmMain::getWMIC(const QString &cmd)
{
    //获取cpu名称：wmic cpu get Name
    //获取cpu核心数：wmic cpu get NumberOfCores
    //获取cpu线程数：wmic cpu get NumberOfLogicalProcessors
    //查询cpu序列号：wmic cpu get processorid
    //查询主板序列号：wmic baseboard get serialnumber
    //查询BIOS序列号：wmic bios get serialnumber
    //查看硬盘：wmic diskdrive get serialnumber
    QProcess p;
    p.start(cmd);
    p.waitForFinished();
    QString result = QString::fromLocal8Bit(p.readAllStandardOutput());
    QStringList list = cmd.split(" ");
    result = result.remove(list.last(), Qt::CaseInsensitive);
    result = result.replace("\r", "");
    result = result.replace("\n", "");
    result = result.simplified();
    return result;
}
QString frmMain::getCpuName()
{
    return getWMIC("wmic cpu get name");
}
QString frmMain::getCpuId()
{
    return getWMIC("wmic cpu get processorid");
}
QString frmMain::getDiskNum()
{
    return getWMIC("wmic diskdrive where index=0 get serialnumber");
}

QProcess使用

bat进程启动运行

QProcess process;
process.start("del /s *.txt");
// same as process.start("del", QStringList() << "/s" << "*.txt");

空格不用管在要执行的路径前和后加上双引号就可以。
比如process.start("D:\Program Files\XiaZaiBa.exe");
写成process.start("\"D:\Program Files\XiaZaiBa.exe\"");就可以了。

process.setWorkingDirectory( "./subdir" );  

process.start( QApplication::applicationDirPath() + "subdir/sub.exe" );  

不用vbs的bat启动，给入监控端口参数启动

QProcess process; QProcessEnvironment env = QProcessEnvironment::systemEnvironment(); 
env.insert("TMPDIR", "C:\\MyApp\\temp"); // Add an environment variable 
process.setProcessEnvironment(env); 
process.start("myapp");

//启用VBS脚本
wscript.exe

		//system("WScript.exe  ../engine/HideRun.vbs");
		SHELLEXECUTEINFOA ShExecInfo;

		ShExecInfo.cbSize = sizeof(SHELLEXECUTEINFOA);
		ShExecInfo.fMask = SEE_MASK_NOCLOSEPROCESS;
		ShExecInfo.hwnd = NULL;
		ShExecInfo.lpVerb = NULL;
		ShExecInfo.lpFile = "I:/QTCreator/meidayunpan/prj_meida/git_lsx/MideaDisk/engine/aria2c.exe";
		ShExecInfo.lpParameters = "--conf-path=aria2.conf";//传出去的参数
		ShExecInfo.lpDirectory = NULL;
		ShExecInfo.nShow = SW_SHOW;
		ShExecInfo.hInstApp = NULL;

		BOOL b_ret = ShellExecuteExA(&ShExecInfo);
		
		
			QProcess* process = new QProcess(this);
	process->start("../engine/aria2c.exe", QStringList() << "--conf-path=aria2.conf");
	QObject::connect(process, SIGNAL(errorOccurred(QProcess::ProcessError)), this, SLOT([&](QProcess::ProcessError){
		switch (error)
		{
		case QProcess::FailedToStart:
			QMessageBox::information(0, "FailedToStart", "FailedToStart");
			break;
		case QProcess::Crashed:
			QMessageBox::information(0, "Crashed", "Crashed");
			break;
		case QProcess::Timedout:
			QMessageBox::information(0, "FailedToStart", "FailedToStart");
			break;
		case QProcess::WriteError:
			QMessageBox::information(0, "Timedout", "Timedout");
			break;
		case QProcess::ReadError:
			QMessageBox::information(0, "ReadError", "ReadError");
			break;
		case QProcess::UnknownError:
			QMessageBox::information(0, "UnknownError", "UnknownError");
			break;
		default:
			QMessageBox::information(0, "default", "default");
			break;
		}
	}));
	//启动
	QObject::connect(process, SIGNAL(started()), this, SLOT([&](){
		QMessageBox::information(0, "start", "start");
	}));
	//状态改变
	QObject::connect(process, SIGNAL(stateChanged(QProcess::ProcessState)), this, SLOT([&](QProcess::ProcessState newState){
		QMessageBox::information(0, "startChange", QString::number(newState));
	}));
	//退出
	QObject::connect(process, SIGNAL(finished(int, QProcess::ExitStatus)), this, SLOT([&](int exitCode, QProcess::ExitStatus exitStatus){
		QMessageBox::information(0, QString::number(exitCode), QString::number(exitStatus));
	}));

界面美化
自定义皮肤
Qt最小化后恢复界面假死冻结

void showEvent(QShowEvent *e){
setAttribute(Qt::WA_Mapped);
QWidget::showEvent(e);
}

QML加载

m_pQuickWidget = new QQuickWidget(this);
m_pQuickWidget->setFixedSize(1131,586);
m_pQuickWidget->setAttribute(Qt::WA_AlwaysStackOnTop);
m_pQuickWidget->setClearColor(QColor(Qt::transparent));
m_pQuickWidget->setSource(QUrl(QStringLiteral("qrc:/UI/Viewer.qml")));
m_pQuickWidget->rootObject()->setWidth(1131);
m_pQuickWidget->rootObject()->setHeight(586);
m_pQuickWidget->move(this->width()/2.0 - m_pQuickWidget->width()/2.0,342);
m_pQuickWidget->show();

内存SQL

1 2	QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE"); db.setDatabaseName(":memory:");

http服务器
大师
Z-order assignment is not a valid widget

用记事本打开对应的ui文件，找到为空的地方，删除即可

常见问题

图片访问，需编辑qrc文件，添加资源，使用：/全路径名访问。
Vs下qt/Qt setting选择项添加相应模块
QPalette::Window表示背景色，QPalette::WindowText表示前景色
qmake -tp vc，qt工程转vc工程，同理，vs下qt选项也可以转qt工程
无法打开stddef与corecrt等文件，需要安装win kits 10 sdk，配置pro目录。或者直接使用vs2017安装更新vs sdk
Qml计时：console.time()  console.endtime()\
Qmake执行失败，路径必须为全英文
类成员线程快速创建，头文件QtConcurrentrun，命名空间QtConcurrent::run
编码换行符错误：
QTextCodec *codec = QTextCodec::codecForName("UTF-8");//情况2
QTextCodec::setCodecForTr(codec);
QTextCodec::setCodecForLocale(codec);
QTextCodec::setCodecForCStrings(codec);
选项/设置/文本编辑：主要是设置成UTF-8格式，再把BOM设置成都添加。
10.构造与析构函数无法解析，执行qmake

指示器样式

1	例如 ::down-arrow,::menu-indicator{} ::up-arrow:disabled,::up-arrow:off{}。

管理员运行

1 2	QMAKE_LFLAGS += /MANIFESTUAC:\"level=\'requireAdministrator\' uiAccess=\'false\'\" #以管理员运行 QMAKE_LFLAGS += /SUBSYSTEM:WINDOWS,\"5.01\" #VS2013 在XP运行

标题栏高度

1	style()->pixelMetric(QStyle::PM_TitleBarHeight); PM_TitleBarHeight点进去你会发现新大陆

获取类属性

const QMetaObject *metaobject = object->metaObject();
int count = metaobject->propertyCount();
for (int i = 0; i < count; ++i) {
QMetaProperty metaproperty = metaobject->property(i);
const char *name = metaproperty.name();
QVariant value = object->property(name);
qDebug() << name << value;
}

每个控件都有ID

1	a.setAttribute(Qt::AA_NativeWindows);可以让每个控件都拥有独立的句柄。

2K,4K屏支持

1
2
3

#if (QT_VERSION > QT_VERSION_CHECK(5,6,0))
QGuiApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
#endif

线程

QThread用法：启动与退出_qthread restart-CSDN博客

http://m.codes51.com/itwd/1338157.html

QT：最简单的方法实现多线程_正在拉磨_新浪博客

Qt使用多线程的一些心得_qt emit 处理时间长-CSDN博客

QT：最简单的方法实现多线程_正在拉磨_新浪博客

换肤

//移除原有样式
style()->unpolish(ui->btn);
//重新设置新的该控件的样式。
style()->polish(ui->btn);

webengine模块发布

1	发布程序的时候带上QtWebEngineProcess.exe+translations文件夹+resources文件夹

启用独立控制台

1	运行文件附带调试输出窗口 CONFIG += console pro

中文编译乱码

#if _MSC_VER >= 1600
#pragma execution_character_set("utf-8")
#endif

Qt creator 的菜单里 编辑-Select Encoding,可以选择编码。以及工具-选项->文本编辑器->行为->文件编码里要选择UTF-8，BOM: 如果是UTF-8则自动添加。

QString::fromLocal8Bit

重复文件保存

QString path = "F:/down/";
QFile m_saveFile(path + strFileName);
int i = 1;
while (m_saveFile.exists()) {
	m_saveFile.setFileName(path + strFileName + QString::number(i));
	++i;
}
int indexPt = strFileName.lastIndexOf('.');
path.append(strFileName.mid(0, indexPt));
path.append(QString::number(i));
path.append(strFileName.mid(indexPt, strFileName.length() - indexPt));
m_saveFile.setFileName(path);

if (m_saveFile.open(QIODevice::WriteOnly))
{	//打开失败
	m_saveFile.write(stuBytes.m_pChar, stuBytes.m_size);
	m_saveFile.close();
}