Translate instructions QT Creator in C ++

[bvox]

Good morning.
I do not understand how to write instructions for Qt 5.4 in C ++ if I take as an example the following instructions generated by Qt Creator. Can you give me a hand? (sorry for my english)

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
<class>prova1</class>
<widget class="QMainWindow" name="prova1">
<property name="geometry">
<rect>
<x>0</x>
<y>0</y>
<width>400</width>
<height>300</height>
</rect>
</property>
<property name="windowTitle">
<string>prova1</string>
</property>
<widget class="QWidget" name="centralWidget">
<widget class="QWidget" name="horizontalLayoutWidget">
<property name="geometry">
<rect>
<x>10</x>
<y>10</y>
<width>160</width>
<height>80</height>
</rect>
</property>
<layout class="QHBoxLayout" name="horizontalLayout">
<item>
<widget class="QLineEdit" name="lineEdit_2"/>
</item>
<item>
<widget class="QLineEdit" name="lineEdit_3"/>
</item>
<item>
<widget class="QLineEdit" name="lineEdit"/>
</item>
</layout>
</widget>
</widget>
<widget class="QMenuBar" name="menuBar">
<property name="geometry">
<rect>
<x>0</x>
<y>0</y>
<width>400</width>
<height>22</height>
</rect>
</property>
</widget>
</widget>
<layoutdefault spacing="6" margin="11"/>
<resources/>
<connections/>
</ui>

[sierdzio]

Why do you want to write this code by hand? It is automatically created by Qt Designer and transformed into C++ during compilation (see the ui_*.h files in your build directory if you want to know how that C++ code looks like). It can be written manually, also in pure C++, if there is a need.

[bvox]

to understand how you place widgets on the form. I can not write three labels in position 1,1 - 100,30 - 300,80
thanks.

[sierdzio]

Static UIs are usually not a good idea. Better use layouts:

QVBoxLayout *layout = new QVBoxLayout(this);
QLabel *label1 = new QLabel;
QLabel *label2 = new QLabel;
QLabel *label3 = new QLabel;
layout->addWidget(label1);
layout->addWidget(label2);
layout->addWidget(label3);

This will give you a more flexible and better-looking UI.

[bvox]

I integrated the class prova1 (prova1.cpp) generated by Qt Creator in this way:

#include "prova1.h"
#include "ui_prova1.h"
#include <QVBoxLayout>
#include <QLabel>
#include <QLayout>

prova1::prova1(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::prova1)
{
    ui->setupUi(this);

    int left = 0;
    int top = 0;
    int width = 50;
    int height = 20;

    QHBoxLayout *hboxlabelRONE = new QHBoxLayout();
    hboxlabelRONE->setGeometry(QRect(0,0,100,30));
    left = 0;
    QLabel *LabelNE = new QLabel ("NE");
    LabelNE->setGeometry(QRect(left,top,width,height));
    left += width;
    QLabel *LabelRO = new QLabel ("RO");
    LabelRO->setGeometry(QRect(left,top,width,height));
    hboxlabelRONE->addWidget(LabelNE);
    hboxlabelRONE->addWidget(LabelRO);

    QHBoxLayout *hboxlabelPADI = new QHBoxLayout();
    hboxlabelPADI->setGeometry(QRect(100,0,80,30));
    left += width;
    QLabel *LabelPA = new QLabel ("PA");
    LabelPA->setGeometry(QRect(left,top,width,height));
    left += width;
    QLabel *LabelDI = new QLabel ("DI");
    LabelDI->setGeometry(QRect(left,top,width,height));
    hboxlabelPADI->addWidget(LabelPA);
    hboxlabelPADI->addWidget(LabelDI);

    QHBoxLayout *hboxlabelBAAL = new QHBoxLayout();
    hboxlabelBAAL->setGeometry(QRect(180,0,80,30));
    left += width;
    QLabel *LabelBA = new QLabel ("BA");
    LabelBA->setGeometry(QRect(left,top,width,height));
    left += width;
    QLabel *LabelAL = new QLabel ("AL");
    LabelAL->setGeometry(QRect(left,top,width,height));
    hboxlabelBAAL->addWidget(LabelBA);
    hboxlabelBAAL->addWidget(LabelAL);

    QWidget *centralWidget = this->centralWidget();
    centralWidget->setLayout(hboxlabelRONE);
    centralWidget->setLayout(hboxlabelPADI);
    centralWidget->setLayout(hboxlabelBAAL);

}

prova1::~prova1()
{
    delete ui;
}

But I just get a form with the label "NE" in position around (0, 1/2 height form) and the label "RO" in position approximately (1/2 width, 1/2 height).
The labels "PA", "DI", "BA", "AL" does not appear on the form.
I do not know how to make them look all 6 labels on the top left. Help me? Thanks.