【qt学习002】各类位置信息和各类标准输入框

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【qt学习002】各类位置信息和各类标准输入框

2024-07-02 01:26:03 223人阅读

不得不吐（赞）槽（扬）一下《Linux窗口程序设计—Qt4精彩实例分析》，书中的示例基本上是不完整的，只给出了相应知识点的实现，若要完整地运行整个工程，这需要读者来添加其余代码。在添加代码的过程中，因为不熟，常常是战战兢兢的，查很多资料，然后才敢往上写点代码，有时候挺浪费时间的。

今天学示例3和4，各类位置信息，各类标准输入框。

在编译时遇见一个错误：undefined reference to vtable for。

查资料找到解决方法，先qmake然后再构建，再运行即可。虽然解决了这个问题，但我完全不清楚错在哪里，网上的意见也都莫衷一是，只能等经验积累了，再来分析问题。

代码：

// geometry.h

#ifndef GEOMETRY_H

#define GEOMETRY_H

#include <QDialog>

#include <QWidget>

#include <QGridLayout>

#include <QFrame>

#include <QString>

#include <QLabel>

class Geometry: public QDialog

{

Q_OBJECT

public:

Geometry(QWidget *parent = 0, Qt::WindowFlags f = 0);

~Geometry();

// 声明所需的空间，主要为QLabel类

QLabel * xLabel;

QLabel * xString;

QLabel * yLabel;

QLabel * yString;

QLabel * frameGeoLabel;

QLabel * frameGeoString;

QLabel * posLabel;

QLabel * posString;

QLabel * geoLabel;

QLabel * geoString;

QLabel * widthLabel;

QLabel * widthString;

QLabel * heightLabel;

QLabel * heightString;

QLabel * rectLabel;

QLabel * rectString;

QLabel * sizeLabel;

QLabel * sizeString;

QGridLayout *layout;

void updateLabel();

protected:

void moveEvent(QMoveEvent*);

void resizeEvent(QResizeEvent*);

};

#endif // GEOMETRY_H

//geometry.cpp

#include "geometry.h"

Geometry::Geometry(QWidget *parent, Qt::WindowFlags f)

:QDialog(parent, f)

{

setWindowTitle("Geometry");

// 创建程序所需的各控件

xString = new QLabel;

xString->setText(tr("x():"));

xLabel = new QLabel;

yString = new QLabel;

yString->setText(tr("y():"));

yLabel = new QLabel;

frameGeoString = new QLabel;

frameGeoString->setText(tr("frameGeometry():"));

frameGeoLabel = new QLabel;

posString = new QLabel;

posString->setText(tr("pos():"));

posLabel = new QLabel;

geoString = new QLabel;

geoString->setText(tr("geometry():"));

geoLabel = new QLabel;

widthString = new QLabel;

widthString->setText(tr("width():"));

widthLabel = new QLabel;

heightString = new QLabel;

heightString->setText(tr("height()"));

heightLabel = new QLabel;

rectString = new QLabel;

rectString->setText(tr("rect():"));

rectLabel = new QLabel;

sizeString = new QLabel;

sizeString->setText(tr("size():"));

sizeLabel = new QLabel;

// 布局

setWindowTitle(tr("GeoMetrys "));

layout = new QGridLayout(this);

layout->addWidget(xString, 0, 0);

layout->addWidget(xLabel,0, 1);

layout->addWidget(yString, 1,0);

layout->addWidget(yLabel, 1, 1);

layout->addWidget(frameGeoString, 2, 0);

layout->addWidget(frameGeoLabel, 2, 1);

layout->addWidget( posString, 3, 0);

layout->addWidget( posLabel, 3, 1);

layout->addWidget( geoString, 4, 0);

layout->addWidget( geoLabel, 4, 1);

layout->addWidget( widthString, 5, 0);

layout->addWidget( widthLabel, 5, 1);

layout->addWidget( heightString, 6, 0);

layout->addWidget( heightLabel, 6, 1);

layout->addWidget( rectString, 7, 0);

layout->addWidget( rectLabel, 7, 1);

layout->addWidget( sizeString, 8, 0);

layout->addWidget( sizeLabel, 8, 1);

layout->setMargin(15);

layout->setSpacing(10);

updateLabel();

}

Geometry::~Geometry()

{

delete xLabel;

delete xString;

delete yLabel;

delete yString;

delete frameGeoLabel;

delete frameGeoString;

delete posLabel;

delete posString;

delete geoLabel;

delete geoString;

delete widthLabel;

delete widthString;

delete heightLabel;

delete heightString;

delete rectLabel;

delete rectString;

delete sizeLabel;

delete sizeString;

delete layout;

}

void Geometry::updateLabel()

{

QString temp;

QString str_x;

xLabel->setText(str_x.setNum(x()));

QString str_y;

yLabel->setText(str_y.setNum(y()));

QString frameGeo;

frameGeo = temp.setNum(frameGeometry().x()) + "," +

temp.setNum(frameGeometry().y()) + "," +

temp.setNum(frameGeometry().width()) + "," +

temp.setNum(frameGeometry().height());

frameGeoLabel->setText(frameGeo);

QString position;

position = temp.setNum(pos().x()) + "," +temp.setNum(pos().y());

posLabel->setText(position);

QString geo;

geo = temp.setNum(geometry().x()) + "," +

temp.setNum(geometry().y()) + "," +

temp.setNum(geometry().width()) + "," +

temp.setNum(geometry().height());

geoLabel->setText(geo);

QString w;

widthLabel->setText(w.setNum(width()));

QString h;

heightLabel->setText(h.setNum(height()));

QString r;

r = temp.setNum(rect().x()) + "," + temp.setNum(rect().y()) + "," +

temp.setNum(rect().width()) + "," + temp.setNum(rect().height());

rectLabel->setText(r);

QString s;

s = temp.setNum(size().width()) + "," + temp.setNum(size().height());

sizeLabel->setText(s);

}

void Geometry::moveEvent(QMoveEvent *) //下面两个函数继承自QWidget，所以毋须再Geometry构造函数中显式调用

{

updateLabel();

}

void Geometry::resizeEvent(QResizeEvent *)

{

updateLabel();

}

//main.cpp

#include <QApplication>

#include <QPushButton>

#include <QLabel>

#include "standarddialogs.h"

#include "geometry.h"

int main(int argc, char *argv[])

{

QApplication a(argc, argv);

// StandardDialogs ct;

// ct.show();

// QPushButton b("Hello World!");

// b.show();

// QObject::connect(&b, SIGNAL(clicked()), &a, SLOT(quit()));

Geometry my;

my.show();

return a.exec();

}

// inputdialog.h

#ifndef INPUTDIALOG_H

#define INPUTDIALOG_H

#include <QDialog>

#include <QLabel>

#include <QPushButton>

#include <QGridLayout>

#include <QString>

#include <QInputDialog>

#include <QLineEdit>

class InputDlg: public QDialog

{

Q_OBJECT

public:

InputDlg();

~InputDlg();

public:

QPushButton *nameButton;

QPushButton *sexButton;

QPushButton *ageButton;

QPushButton *statureButton;

QLabel *label1;

QLabel *label2;

QLabel *label3;

QLabel *label4;

QLabel *nameLabel;

QLabel *sexLabel;

QLabel *ageLabel;

QLabel *statureLabel;

QGridLayout *layout;

private slots:

void slotName();

void slotSex();

void slotAge();

void slotStature();

};

#endif // INPUTDIALOG_H

// inputdialog.cpp

#include "inputdialog.h"

InputDlg::InputDlg()

{

setWindowTitle(tr("Input Dialog"));

// 创建各标签对象

label1 = new QLabel(tr("Name:"));

label2 = new QLabel(tr("Sex:"));

label3 = new QLabel(tr("Age:"));

label4 = new QLabel(tr("High:"));

// 创建各显示标签

nameLabel = new QLabel(tr("LiMing"));

nameLabel->setFrameStyle(QFrame::Panel|QFrame::Sunken); //QFrame::Panel 0x0002 QFrame draws a panel to make the contents appear raised or sunken

sexLabel = new QLabel(tr("Male"));

sexLabel->setFrameStyle(QFrame::Panel | QFrame::Raised);

ageLabel = new QLabel(tr("25"));

ageLabel->setFrameStyle(QFrame::Panel | QFrame::Raised);

statureLabel = new QLabel(tr("175.5"));

statureLabel->setFrameStyle(QFrame::Panel | QFrame::Raised);

// 创建各修改按钮

nameButton = new QPushButton;

// nameButton->setIcon(QIcon("btn.png"));

sexButton = new QPushButton;

// sexButton->setIcon(QIcon("btn.png"));

ageButton = new QPushButton;

// ageButton->setIcon(QIcon("btn.png"));

statureButton = new QPushButton;

// statureButton->setIcon(QIcon("btn.png"));

// 布局

layout = new QGridLayout(this);

layout->addWidget(label1, 0, 0);

layout->addWidget(nameLabel, 0, 1);

layout->addWidget(nameButton, 0, 2);

layout->addWidget(label2, 1, 0);

layout->addWidget(sexLabel, 1, 1);

layout->addWidget(sexButton, 1, 2);

layout->addWidget(label3, 2, 0);

layout->addWidget(ageLabel, 2, 1);

layout->addWidget(ageButton, 2, 2);

layout->addWidget(label4, 3, 0);

layout->addWidget(statureLabel, 3, 1);

layout->addWidget(statureButton, 3, 2);

// 连接信号与槽函数

connect(nameButton, SIGNAL(clicked()), this, SLOT(slotName()));

connect(sexButton, SIGNAL(clicked()), this, SLOT(slotSex()));

connect(ageButton, SIGNAL(clicked()), this, SLOT(slotAge()));

connect(statureButton, SIGNAL(clicked()), this, SLOT(slotStature()));

}

InputDlg::~InputDlg()

{

delete label1;

delete label2;

delete label3;

delete label4;

delete layout;

delete nameLabel;

delete ageLabel;

delete sexLabel;

delete statureLabel;

delete nameButton;

delete sexButton;

delete ageButton;

delete statureButton;

}

void InputDlg::slotName()

{

bool ok;

QString name = QInputDialog::getText(this, tr("User Name"), // this 表示父窗口，是QWidget对象指针, The QWidget class is the base class of all user interface objects.

tr("Please input new name:"), QLineEdit::Normal, nameLabel->text(), &ok);

if(ok & !name.isEmpty()) // 此处书中有错误，将&写成了&&，查了qt的help文档，没发现有&&这个运算符号

{

nameLabel->setText(name);

}

void InputDlg::slotSex()

{

QStringList list;

list << tr("male") << tr("female");

bool ok;

QString sex = QInputDialog::getItem(this, tr("Sex"),

tr("Please select sex:"), list, 0, false, &ok);

if(ok)

sexLabel->setText(sex);

}

void InputDlg::slotAge()

{

bool ok;

int age = QInputDialog::getInteger(this, tr("User Age"),

tr("Please input age:"), ageLabel->text().toInt(), 0, 150, 1, &ok);

if (ok)

ageLabel->setText(QString(tr("%1")).arg(age));

// 数字显示成字符串的方法，也说明setText必须接收字符串输入，原型为 void setText(const QString &)

}

void InputDlg::slotStature()

{

bool ok;

double d = QInputDialog::getDouble(this, tr("Stature"),

tr("Please input stature:"), 175.00, 0, 230.00, 1, &ok);

if(ok)

statureLabel->setText(QString(tr("%1")).arg(d));

}

// main.cpp

#include <QApplication>

#include <QPushButton>

#include <QLabel>

#include "standarddialogs.h"

#include "geometry.h"

#include "inputdialog.h"

int main(int argc, char *argv[])

{

QApplication a(argc, argv);

// StandardDialogs ct;

// ct.show();

// QPushButton b("Hello World!");

// b.show();

// QObject::connect(&b, SIGNAL(clicked()), &a, SLOT(quit()));

// Geometry my;

// my.show();

InputDlg person;

person.show();

return a.exec();

}

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