Unable to focus and give input to widgets in Qt5 - c++

Question

Issue Resolved: Q_OBJECT macro was necessary and proper signal slot declarations are also important for any other handles.
I am unable to focus on any input type widgets like QTextEdit,QListWidget etc.
Note: There are no compile time or runtime errors.
Update: QSplitter is working properly! I have a QListWidget, whose items I click but they are highlighted only when I make the next move with the splitter.
I have a MainWindow class derived from QMainWindow as declared in main_window.h:
class MainWindow : public QMainWindow{
Q_OBJECT
public:
MainWindow(QWidget *parent = 0);
//some other members like menu and statusbar here
}
I have another class called Stack derived from QWidget defined in stack.h:
class Stack: public QWidget{
public:
Stack(QWidget *parent=0);
//some other members
}
Constructor of Stack as in stack.cpp :
Stack::Stack(QWidget *parent):QWidget(parent){
main = new QHBoxLayout;
handle = new QSplitter;
setupList();
setupScreens();
//above functions add the widgets to the handle splitter
main->addWidget(handle);
setLayout(main);
}
If i open up this widget in a separate window from the MainWindow using test->show(), the things work as expected/as i want.
But doing this in the MainWindow constructor, renders it unclickable.
MainWindow::MainWindow(QWidget *parent):QMainWindow(parent){
Stack *test = new Stack(this);
//test->show();
setCentralWidget(test);
}
This is strange. Why am i not able to focus any widget that can take input e.g. QTextEdit,QListWidget or click any QPushButton widget?

Answer 1

Please compile following code, it was working..you are getting focus and edit on QTextEdit...
stack.h
#include <QWidget>
class Stack: public QWidget
{
Q_OBJECT
public:
Stack(QWidget *parent = 0);
~Stack(void);
};
stack.cpp
#include "Stack.h"
#include<QTextEdit>
#include<QHBoxLayout>
Stack::Stack(QWidget *parent):QWidget(parent){
QHBoxLayout* main = new QHBoxLayout;
QTextEdit *test = new QTextEdit;
main->addWidget(test);
//other things added to main layout
setLayout(main);
}
Stack::~Stack(void)
{
}
mainwindow1.h
#ifndef MAINWINDOW1_H
#define MAINWINDOW1_H
#include <QtGui/QMainWindow>
//#include "ui_mainwindow1.h"
class Mainwindow1 : public QMainWindow
{
Q_OBJECT
public:
Mainwindow1(QWidget *parent = 0, Qt::WFlags flags = 0);
~Mainwindow1();
private:
//Ui::Mainwindow1Class ui;
};
#endif // MAINWINDOW1_H
mainwindow1.cpp
#include "mainwindow1.h"
#include "Stack.h"
#include <QTextEdit>
Mainwindow1::Mainwindow1(QWidget *parent, Qt::WFlags flags)
: QMainWindow(parent, flags)
{
Stack *test = new Stack;
setCentralWidget(test);
}
Mainwindow1::~Mainwindow1()
{
}
main.cpp
#include "mainwindow1.h"
#include <QtGui/QApplication>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
Mainwindow1 w;
w.show();
return a.exec();
}

Answer 2

If some1 would find this looking for answer on how to set focus on input widget from UI in QT5 you can just use:
ui->plainTextEdit->setFocus();