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POC++ /Qt Proper way to access ui from another class in qt //Edited
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  1. POC++ /Qt Proper way to access ui from another class in qt //Edited
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    copied!<p>I'm trying to access the ui member which is private in the MainWindow class.</p> <p>I would like to update a lineEdit (Xvaldisp) when I release the mousebutton (with the amount the mouse moved)from a gl widget. </p> <p>After searching a bit around I found that I need to create a function/Method in mainwindow then access it through a pointer to Mainwindow from my GLWidget</p> <p><strong>The problem:</strong></p> <p>The lineEdit remains blank, The method( displaymessage() ) that should update it seems to get called.</p> <p>To check that I've created a string(str) to see if displaymessage was getting called, this string gets updated with a new value when displaymessage() gets called.</p> <p>The on_Button_clicked() method below displaymessage() also updates the same lineEdit when a pushbutton is clicked and works just fine it displays the content of str </p> <p>Here's my code:</p> <p><strong>glwidget.h</strong></p> <pre><code>#ifndef GLWIDGET_H #define GLWIDGET_H #include &lt;QGLWidget&gt; #include &lt;QTimer&gt; #include &lt;QMouseEvent&gt; #include "mainwindow.h" #include &lt;QObject&gt; #include &lt;QLineEdit&gt; class GLWidget : public QGLWidget { Q_OBJECT public: explicit GLWidget(QWidget *parent = 0); void mousePressEvent(QMouseEvent *e); void mouseReleaseEvent(QMouseEvent *e); void initializeGL(); void paintGL(); void resizeGL(int w, int h); private: QTimer timer; QPoint pointMpressed; QPoint diff; protected: signals: void valueCh(); }; #endif // GLWIDGET_H </code></pre> <p><strong>mainwindow.h</strong></p> <pre><code>#ifndef MAINWINDOW_H #define MAINWINDOW_H #include &lt;QMainWindow&gt; #include &lt;QLineEdit&gt; #include &lt;QObject&gt; #include "glwidget.h" namespace Ui { class MainWindow; } class MainWindow : public QMainWindow { Q_OBJECT public: MainWindow(QWidget *parent = 0); ~MainWindow(); public slots: void on_Button_clicked(); void displayMessage(); protected: void changeEvent(QEvent *e); private: Ui::MainWindow *ui; }; #endif // MAINWINDOW_H </code></pre> <p><strong>glwidget.cpp.</strong></p> <pre><code>#include "glwidget.h" #include &lt;GL/glut.h&gt; GLWidget::GLWidget(QWidget *parent) : QGLWidget(parent) { connect (&amp;timer,SIGNAL(timeout()),this,SLOT(updateGL())); timer.start(16); } void GLWidget::mousePressEvent(QMouseEvent *e){ pointMpressed=e-&gt;pos(); } void GLWidget::mouseReleaseEvent(QMouseEvent *e){ diff=(e-&gt;pos())- pointMpressed ; //calculate position difference between click and release MainWindow *mwd; mwd= new MainWindow; // mwd-&gt;displayMessage(); //tried this first then with signals and slots below same result QObject::connect(this, SIGNAL(valueCh()), mwd ,SLOT(displayMessage()) ); emit valueCh(); delete mwd; } void GLWidget::initializeGL(){ } void GLWidget::resizeGL(int w, int h){ } </code></pre> <p><strong>mainwindow.cpp</strong></p> <pre><code>#include "mainwindow.h" #include "ui_mainwindow.h" #include "glwidget.h" QString str="none activated"; //I used this string to check if the methods were getting called MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow) { ui-&gt;setupUi(this); } MainWindow::~MainWindow() { delete ui; } void MainWindow::changeEvent(QEvent *e) { QMainWindow::changeEvent(e); switch (e-&gt;type()) { case QEvent::LanguageChange: ui-&gt;retranslateUi(this); break; default: break; } } void MainWindow::displayMessage(){ //this method should update the lineEdit (Xvaldisp) the lineEdit however remains blank but str gets updated ui-&gt;Xvaldisp-&gt;setText(str); str ="displayMessage hs rn"; //displaymessage has run } void MainWindow::on_Button_clicked(){ // this is a pushbutton(Button) that once pushed also updates the same lineEdit(Xvaldisp) this works just fine If I clicked and released the mouse before on the GLWidget it would show the by displaymessage() updated string else it would be the orginal value ui-&gt;Xvaldisp-&gt;setText(str); } </code></pre>
 

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