Qt5开发及实例学习之位置函数

一、新建GUI应用，项目名称"Geometry"，基类选择"QDialog",类名为"Geometry",取消"建立界面"。

main.cpp不变：

#include "geometry.h"
#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Geometry w;
    w.show();
    
    return a.exec();
}

二、Geometry类继承自QDialog类，在头文件中声明须要的控件[QLabel]以及所须要的函数

#ifndef GEOMETRY_H
#define GEOMETRY_H

#include <QDialog>
#include <QLabel>
#include <QGridLayout>

class Geometry : public QDialog
{
    Q_OBJECT
    
public:
    Geometry(QWidget *parent = 0);
    ~Geometry();
    void updateLabel();
private:
    QLabel *xLabel;
    QLabel *xValueLabel;
    QLabel *yLabel;
    QLabel *yValueLabel;
    QLabel *FrmLabel;
    QLabel *FrmValueLabel;
    QLabel *posLabel;
    QLabel *posValueLabel;
    QLabel *geoLabel;
    QLabel *geoValueLabel;
    QLabel *widthLabel;
    QLabel *widthValueLabel;
    QLabel *heightLabel;
    QLabel *heightValueLabel;
    QLabel *rectLabel;
    QLabel *rectValueLabel;
    QLabel *sizeLabel;
    QLabel *sizeValueLabel;
    QGridLayout *mainLayout;
protected:
    void moveEvent(QMoveEvent *);
    void resizeEvent(QResizeEvent *);
};

#endif // GEOMETRY_H

三、在构造函数中完成控件的建立以及初始化工做
四、updateLabel()函数完成得到各位置函数的信息并显示功能
五、重定义QWidget的moveEvent()函数，响应对话框的移动事件，使得窗体在被移动时可以同步更新个函数的显示结果。
六、重定义QWidget的resizeEvent()函数，响应对话框的大小调整事件，使得窗体大小改变时可以同步更新个函数的显示结果。

#include "geometry.h"

Geometry::Geometry(QWidget *parent)
    : QDialog(parent)
{
    setWindowTitle(tr("Geometry"));
    xLabel =new QLabel(tr("x():"));
    xValueLabel =new QLabel;
    yLabel =new QLabel(tr("y():"));
    yValueLabel =new QLabel;
    FrmLabel =new QLabel(tr("Frame:"));
    FrmValueLabel =new QLabel;
    posLabel =new QLabel(tr("pos():"));
    posValueLabel =new QLabel;
    geoLabel =new QLabel(tr("geometry():"));
    geoValueLabel =new QLabel;
    widthLabel =new QLabel(tr("width():"));
    widthValueLabel =new QLabel;
    heightLabel =new QLabel(tr("height():"));
    heightValueLabel =new QLabel;
    rectLabel =new QLabel(tr("rect():"));
    rectValueLabel =new QLabel;
    sizeLabel =new QLabel(tr("size():"));
    sizeValueLabel =new QLabel;

    mainLayout =new QGridLayout(this);
    mainLayout->addWidget(xLabel,0,0);
    mainLayout->addWidget(xValueLabel,0,1);
    mainLayout->addWidget(yLabel,1,0);
    mainLayout->addWidget(yValueLabel,1,1);
    mainLayout->addWidget(posLabel,2,0);
    mainLayout->addWidget(posValueLabel,2,1);
    mainLayout->addWidget(FrmLabel,3,0);
    mainLayout->addWidget(FrmValueLabel,3,1);
    mainLayout->addWidget(geoLabel,4,0);
    mainLayout->addWidget(geoValueLabel,4,1);
    mainLayout->addWidget(widthLabel,5,0);
    mainLayout->addWidget(widthValueLabel,5,1);
    mainLayout->addWidget(heightLabel,6,0);
    mainLayout->addWidget(heightValueLabel,6,1);
    mainLayout->addWidget(rectLabel,7,0);
    mainLayout->addWidget(rectValueLabel,7,1);
    mainLayout->addWidget(sizeLabel,8,0);
    mainLayout->addWidget(sizeValueLabel,8,1);

    updateLabel();
}

Geometry::~Geometry()
{
    
}

void Geometry::updateLabel()
{
    QString xStr;                      	//得到x()函数的结果并显示
    xValueLabel->setText(xStr.setNum(x()));

    QString yStr;                      	//得到y()函数的结果并显示
    yValueLabel->setText(yStr.setNum(y()));

    QString frameStr;                 	//得到frameGeometry()函数的结果并显示
    QString tempStr1,tempStr2,tempStr3,tempStr4;
    frameStr = tempStr1.setNum(frameGeometry().x())+","+tempStr2.setNum(frameGeometry().y())+","+tempStr3.setNum(frameGeometry().width())+","+tempStr4.setNum(frameGeometry().height());
    FrmValueLabel->setText(frameStr);

    QString positionStr;            	//得到pos()函数的结果并显示
    QString tempStr11,tempStr12;
    positionStr =tempStr11.setNum(pos().x())+","+tempStr12.setNum(pos().y());
    posValueLabel->setText(positionStr);

    QString geoStr;               		//得到geometry()函数的结果并显示
    QString tempStr21,tempStr22,tempStr23,tempStr24;
    geoStr =tempStr21.setNum(geometry().x())+","+tempStr22.setNum(geometry().y())+","+tempStr23.setNum(geometry().width())+","+tempStr24.setNum(geometry().height());
    geoValueLabel->setText(geoStr);

    QString wStr,hStr;                  //得到width()、height()函数的结果并显示
    widthValueLabel->setText(wStr.setNum(width()));
    heightValueLabel->setText(hStr.setNum(height()));

    QString rectStr;                    //得到rect()函数的结果并显示
    QString tempStr31,tempStr32,tempStr33,tempStr34;
    rectStr =tempStr31.setNum(rect().x())+","+tempStr32.setNum(rect().y())+","+tempStr33.setNum(/*rect().width()*/width())+","+tempStr34.setNum(height()/*rect().height()*/);
    rectValueLabel->setText(rectStr);

    QString sizeStr;                 	//得到size()函数的结果并显示
    QString tempStr41,tempStr42;
    sizeStr =tempStr41.setNum(size().width())+","+tempStr42.setNum(size().height());
    sizeValueLabel->setText(sizeStr);
}

void Geometry:: moveEvent(QMoveEvent *)
{
    updateLabel();
}

void Geometry::resizeEvent(QResizeEvent *)
{
    updateLabel();
}