QT learning 23 layout manager (II)

Qt Study 23 Layout manager （ Two ）

Layout manager

• In layout manager ratio
• By default, in an equal proportion Update the size of the component
• You can customize Component size update ratio
• QBoxLayout Scale factor setting in
  • void setStretch(int index, int stretch)
  • bool setStretchFactor(QWidget* widget, int stretch)
  • bool setStretchFactor(QLayout* layout, int stretch)

Programming experiment - A preliminary study of the proportional coefficient

Add the function of setting the scale factor to the code in the previous section

void Widget::testVBoxLayout()
{
    
    //  Add window controls to layout manager 
    //  Layout manager sets the spacing between controls 
    //  Set the scale factor 
    layout->setStretch(0, 1);
    layout->setStretch(1, 2);
    layout->setStretch(2, 3);
    layout->setStretch(3, 4);
    //  Set the layout manager of the current window 
}
void Widget::testHBoxLayout()
{
    
    //  Add window controls to layout manager 
    //  Layout manager sets the spacing between controls 
    //  Set the scale factor 
    layout->setStretchFactor(&TestBtn1, 1);
    layout->setStretchFactor(&TestBtn2, 3);
    layout->setStretchFactor(&TestBtn3, 1);
    layout->setStretchFactor(&TestBtn4, 4);
    //  Set the layout manager of the current window 
}
void Widget::testVHBoxLayout()
{
    
    // ...
    vLayout->setStretchFactor(hLayout1, 1);
    vLayout->setStretchFactor(hLayout2, 2);
    // ...
}

• The initial size of the component is Independent of layout manager Set up , therefore There is no guarantee that the size of the component always conforms to the setting of the scale factor

QGridLayout Layout manager

• With grid （ A two-dimensional ） Manage interface components in a way

• QGridLayout Scale factor setting in
  • void setColumnStretch(int column, int stretch)
  • void setRowStretch(int row, int stretch)

Programming experiment - QGridLayout

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include <QPushButton>

class Widget : public QWidget
{
    
    Q_OBJECT
private:
    QPushButton TestBtn1;
    QPushButton TestBtn2;
    QPushButton TestBtn3;
    QPushButton TestBtn4;
    void initBtn();
    void testGridLayout1();
    void testGridLayout2();
public:
    Widget(QWidget *parent = 0);
    ~Widget();
};

#endif // WIDGET_H

#include "Widget.h"
#include <QGridLayout>

Widget::Widget(QWidget *parent) : QWidget(parent),
    TestBtn1(this), TestBtn2(this), TestBtn3(this), TestBtn4(this)
{
    
    initBtn();
// testGridLayout1();
    testGridLayout2();
}

Widget::~Widget()
{
    

}

void Widget::initBtn()
{
    
    TestBtn1.setText("Test Button 1");
    TestBtn1.setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
    TestBtn1.setMinimumSize(160, 30);

    TestBtn2.setText("Test Button 2");
    TestBtn2.setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
    TestBtn2.setMinimumSize(160, 30);

    TestBtn3.setText("Test Button 3");
    TestBtn3.setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
    TestBtn3.setMinimumSize(160, 30);

    TestBtn4.setText("Test Button 4");
    TestBtn4.setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
    TestBtn4.setMinimumSize(160, 30);
}

void Widget::testGridLayout1()
{
    
    QGridLayout* layout = new QGridLayout();
    layout->setSpacing(10);
    //  Grid layout management add button components 
    layout->addWidget(&TestBtn1, 0, 0);
    layout->addWidget(&TestBtn2, 0, 1);
    layout->addWidget(&TestBtn3, 1, 0);
    layout->addWidget(&TestBtn4, 1, 1);
    //  Set row scale factor 
    layout->setRowStretch(0, 1);
    layout->setRowStretch(1, 2);
    //  Set the column scale factor 
    layout->setColumnStretch(0, 3);
    layout->setColumnStretch(1, 4);
    setLayout(layout);
}

void Widget::testGridLayout2()
{
    
    QGridLayout* layout = new QGridLayout();
    layout->setSpacing(10);
    //  Grid layout management add button components across grids 
    layout->addWidget(&TestBtn1, 0, 0, 2, 1);
    layout->addWidget(&TestBtn2, 0, 1, 2, 1);
    layout->addWidget(&TestBtn3, 2, 0, 1, 2);
    layout->addWidget(&TestBtn4, 3, 0, 1, 2);
    setLayout(layout);
}

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

int main(int argc, char *argv[])
{
    
    QApplication a(argc, argv);
    Widget w;
    w.show();

    return a.exec();
}

• Nesting of layout managers
  • QGridLayout Support Nest other layout managers Become its management object

Summary

• QGridLayout With Grid mode Manage components
• QGridLayout Components in can Span multiple grids as needed
• QBoxLayout and QGridLayout Support ratio The concept of
• ratio Determines the size of the component Relative change