First, hello to all. My name is Juan Carlos and this is my first message.

I have an MDI application (QT 4.5.3) that opens a widget that contains a table (QTableWidget) My problem is that the widget does not fit the size of the table when it opens, but if I try to increase the size of the widget, it automatically adjusts to the correct size. What am I doing wrong?

The problematic code is:

main.cpp

Qt Code: 
  1. #include <QApplication>
  2.  
  3. #include "mainwindow.h"
  4.  
  5. int main(int argc, char *argv[])
  6. {
  7.     QApplication app(argc, argv);
  8.  
  9.     MyMDI mainMDI;
  10.     mainMDI.show();
  11.  
  12.     return app.exec();
  13. }
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mainwindow.cpp

Qt Code: 
  1. #include "mainwindow.h"
  2.  
  3. #include <QHeaderView>
  4. #include <QMenuBar>
  5.  
  6. MyTableWidget::MyTableWidget(QWidget *parent) : QWidget(parent)
  7. {
  8.     m_tableValues = 0;
  9.     m_layout = 0;
  10. }
  11.  
  12. void MyTableWidget::showData()
  13. {
  14.     QStringList headers;
  15.     headers << tr("C1") << tr("C2") << ("C3");
  16.  
  17.     int maxrows = 300;
  18.  
  19.     m_tableValues = new QTableWidget(maxrows, 3, this);
  20.     m_layout = new QGridLayout(this);
  21.  
  22.     m_tableValues->verticalHeader()->hide();
  23.     m_tableValues->setHorizontalHeaderLabels(headers);
  24.     m_tableValues->verticalHeader()->setUpdatesEnabled(false);
  25.  
  26.     for(int i = 0; i < maxrows; i++) {
  27.         QTableWidgetItem *newItem = new QTableWidgetItem(tr("%L1").arg(1000*i+1));
  28.         newItem->setTextColor(Qt::black);
  29.         newItem->setTextAlignment(Qt::AlignRight | Qt::AlignVCenter);
  30.         m_tableValues->setItem(i, i % 3, newItem);
  31.     }
  32.  
  33.     m_tableValues->resizeColumnsToContents();
  34.     m_tableValues->resizeRowsToContents();
  35.  
  36.     m_tableValues->setMinimumSize(m_tableValues->minimumSizeHint());
  37.  
  38.     m_tableValues->verticalHeader()->setUpdatesEnabled(true);
  39.  
  40.     m_layout->addWidget(m_tableValues);
  41. }
  42.  
  43. QSize MyTableWidget::minimumSizeHint() const
  44. {
  45.     QSize size;
  46.  
  47.     if(!m_tableValues) {
  49.         size = aux.minimumSizeHint();
  50.         return size;
  51.     }
  52.  
  53.     int width = 0;
  54.     for(int c = 0; c < m_tableValues->columnCount(); c++) {
  55.         width += m_tableValues->columnWidth(c);
  56.     }
  57.  
  58.     size.setWidth(width+50);
  59.     size.setHeight(200);
  60.  
  61.     return size;
  62. }
  63.  
  64. QSize MyTableWidget::sizeHint() const
  65. {
  66.     return minimumSizeHint();
  67. }
  68.  
  69. /* -------------------------------------------------- */
  70. /* -------------------------------------------------- */
  71. /* -------------------------------------------------- */
  72.  
  73. MyMdiWindow::MyMdiWindow(QWidget *parent) : QWidget(parent)
  74. {
  75.     m_layout = new QVBoxLayout(this);
  76.     m_table = new MyTableWidget(this);
  77.     m_layout->addWidget(m_table);
  78.     setLayout(m_layout);
  79. }
  80.  
  81. void MyMdiWindow::showMyTableWidget()
  82. {
  83.     m_table->showData();
  84.     m_table->setMinimumSize(m_table->sizeHint());
  85. }
  86.  
  87. /* -------------------------------------------------- */
  88. /* -------------------------------------------------- */
  89. /* -------------------------------------------------- */
  90.  
  91. MyMDI::MyMDI()
  92. {
  93.     m_mdiArea = new QMdiArea;
  94.     m_mdiArea->setHorizontalScrollBarPolicy(Qt::ScrollBarAsNeeded);
  95.     m_mdiArea->setVerticalScrollBarPolicy(Qt::ScrollBarAsNeeded);
  96.     setCentralWidget(m_mdiArea);
  97.  
  98.     m_openAct = new QAction(tr("Open"), this);
  99.     connect(m_openAct, SIGNAL(triggered()),this, SLOT(open()));
  100.  
  101.     m_Menu = menuBar()->addMenu(tr("&Menu"));
  102.     m_Menu->addAction(m_openAct);
  103. }
  104.  
  105. void MyMDI::open()
  106. {
  107.     MyMdiWindow* mdiWindow = new MyMdiWindow(this);
  108.     m_mdiArea->addSubWindow(mdiWindow);
  109.     mdiWindow->showMyTableWidget();
  110.     mdiWindow->show();
  111. }
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mainwindow.h

Qt Code: 
  1. #ifndef MAINWINDOW_H
  2. #define MAINWINDOW_H
  3.  
  4. #include <QMainWindow>
  5. #include <QMdiArea>
  6. #include <QAction>
  7. #include <QMenu>
  8. #include <QWidget>
  9. #include <QTableWidget>
  10. #include <QGridLayout>
  11.  
  12. class MyTableWidget : public QWidget
  13. {
  14.     Q_OBJECT
  15.  
  16. protected:
  17.     QTableWidget* m_tableValues;
  18.     QGridLayout* m_layout;
  19.  
  20. public:
  21.     MyTableWidget(QWidget* parent = 0);
  22.     void showData();
  23.  
  24.     QSize minimumSizeHint() const;
  25.     QSize sizeHint() const;
  26. };
  27.  
  28. /* -------------------------------------------------- */
  29. /* -------------------------------------------------- */
  30. /* -------------------------------------------------- */
  31.  
  32. class MyMdiWindow : public QWidget
  33. {
  34.     Q_OBJECT
  35.  
  36. protected:
  37.     MyTableWidget* m_table;
  38.     QVBoxLayout* m_layout;
  39.  
  40. public:
  41.     MyMdiWindow(QWidget *parent = 0);
  42.     void showMyTableWidget();
  43.  
  44. };
  45.  
  46. /* -------------------------------------------------- */
  47. /* -------------------------------------------------- */
  48. /* -------------------------------------------------- */
  49.  
  50. class MyMDI : public QMainWindow
  51. {
  52.     Q_OBJECT
  53.  
  54. public:
  55.     MyMDI();
  56.  
  57. private slots:
  58.     void open();
  59.  
  60. private:
  61.     QMdiArea *m_mdiArea;
  62.  
  63.     QMenu *m_Menu;
  64.     QAction *m_openAct;
  65.     QAction *m_exitAct;
  66.  
  67. };
  68.  
  69. #endif // MAINWINDOW_H
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Thanks in advance.

P.D. Sorry for my English.