kbruch/src/taskview.cpp

   1 /***************************************************************************
   2                           taskview.cpp  -  The task window
   3                              -------------------
   4     begin                : Tue Feb 08 13:41:00 CET 2002
   5     copyright            : (C) 2001 - 2004 by Sebastian Stein
   6     email                : seb.kde@hpfsc.de
   7  ***************************************************************************/
   8
   9 /***************************************************************************
  10  *                                                                         *
  11  *   This program is free software; you can redistribute it and/or modify  *
  12  *   it under the terms of the GNU General Public License as published by  *
  13  *   the Free Software Foundation; either version 2 of the License, or     *
  14  *   (at your option) any later version.                                   *
  15  *                                                                         *
  16  ***************************************************************************/
  17
  18 #include "taskview.h"
  19 #include "taskview.moc"
  20
  21 /* these includes are needed for KDE support */
  22 #include <klocale.h>
  23 #include <kmessagebox.h>
  24 #include <kapplication.h>
  25 #include <knumvalidator.h>
  26
  27 /* these includes are needed for Qt support */
  28 #include <qlabel.h>
  29 #include <qlayout.h>
  30 #include <qlineedit.h>
  31 #include <qpushbutton.h>
  32 #include <qtooltip.h>
  33 #include <qwhatsthis.h>
  34
  35 /* standard C++ library includes */
  36 #include <math.h>
  37
  38 /* ----- public member functions ----- */
  39
  40 /* constructor */
  41 TaskView::TaskView(QWidget * parent, const char * name, bool padd_sub,
  42                   bool pmul_div, unsigned int pnr_ratios, unsigned int pmax_md):
  43                 ExerciseBase(parent, name), add_sub(padd_sub), mul_div(pmul_div),
  44                 nr_ratios(pnr_ratios), max_md(pmax_md)
  45 {
  46 #ifdef DEBUG
  47         kdDebug() << "constructor TaskView()" << endl;
  48 #endif
  49
  50         curr_nr_ratios = nr_ratios;
  51
  52         /* create a new task */
  53         QApplication::setOverrideCursor(waitCursor); /* show the sand clock */
  54         current_task.create_task(max_md, nr_ratios, add_sub, mul_div);
  55         QApplication::restoreOverrideCursor(); /* show the normal cursor */
  56
  57         // the next thing to do on a button click would be to check the entered
  58         // result
  59         m_currentState = _CHECK_TASK;
  60
  61         baseWidget = new QWidget(this, "baseWidget");
  62         baseGrid = new QGridLayout(this, 1, 1, 0, -1, "baseGrid");
  63         baseGrid->addWidget(baseWidget, 0, 0);
  64
  65         // this is a VBox
  66         realLayout = new QVBoxLayout(baseWidget, 5, 5, "realLayout");
  67
  68         // add a spacer at the top of the VBox
  69         QSpacerItem * v_spacer = new QSpacerItem(1, 1);
  70         realLayout->addItem(v_spacer);
  71
  72         // now a line holding the task, input fields and result
  73         QHBoxLayout * taskLineHBoxLayout = new QHBoxLayout(5, "taskLineHBoxLayout");
  74         realLayout->addLayout(taskLineHBoxLayout);
  75
  76         // first left is the task widget
  77         m_taskWidget = new TaskWidget(baseWidget, "m_taskWidget", current_task);
  78         taskLineHBoxLayout->addWidget(m_taskWidget);
  79
  80         // now we have the input fields aligned in a VBox
  81         QVBoxLayout * inputLayout = new QVBoxLayout(5, "inputLayout");
  82         taskLineHBoxLayout->addLayout(inputLayout);
  83
  84         // to validate, that the input is an int
  85         KIntValidator *valnum = new KIntValidator( this );
  86
  87         /* add input box so the user can enter numerator */
  88         numer_edit = new QLineEdit(baseWidget, "numer_edit");
  89         numer_edit->setValidator( valnum ); // use the int validator
  90         QToolTip::add(numer_edit, i18n("Enter the numerator of your result"));
  91         inputLayout->addWidget(numer_edit);
  92
  93         /* add a line between the edit boxes */
  94         edit_line = new QFrame(baseWidget, "edit_line");
  95         edit_line->setGeometry(QRect(100, 100, 20, 20));
  96         edit_line->setFrameStyle(QFrame::HLine | QFrame::Sunken);
  97         inputLayout->addWidget(edit_line);
  98
  99         /* add input box so the user can enter denominator */
 100         deno_edit = new QLineEdit(baseWidget, "deno_edit");
 101         deno_edit->setValidator( valnum ); // use the int validator
 102         QToolTip::add(deno_edit, i18n("Enter the denominator of your result"));
 103         inputLayout->addWidget(deno_edit);
 104
 105         // next is the result widget
 106         m_resultWidget = new ResultWidget(baseWidget, "m_resultWidget", *new ratio());
 107         taskLineHBoxLayout->addWidget(m_resultWidget);
 108
 109         // at the right end we have a label just showing CORRECT or WRONG
 110         result_label = new QLabel(baseWidget, "result_label");
 111         result_label->setText(i18n("WRONG"));
 112         taskLineHBoxLayout->addWidget(result_label);
 113         result_label->hide();
 114
 115         // add another spacer in the middle of the VBox
 116         v_spacer = new QSpacerItem(1, 1, QSizePolicy::Expanding, QSizePolicy::Minimum);
 117         taskLineHBoxLayout->addItem(v_spacer);
 118
 119         // --- that is the end of the horizontal line ---
 120
 121         // add another spacer in the middle of the VBox
 122         v_spacer = new QSpacerItem(1, 1);
 123         realLayout->addItem(v_spacer);
 124
 125         // the lower part of the VBox holds just a right aligned button
 126         QHBoxLayout * lowerHBox = new QHBoxLayout(1, "lowerHBox");
 127         realLayout->addLayout(lowerHBox);
 128         lowerHBox->addStretch(100);
 129
 130         // the right aligned button
 131         m_checkButton = new QPushButton( baseWidget, "m_checkButton" );
 132         m_checkButton->setText(i18n("&Check Task"));
 133         m_checkButton->setDefault(true); // is the default button of the dialog
 134         QToolTip::add(m_checkButton, i18n("Click on this button to check your result. The button will not work if you have not entered a result yet."));
 135         lowerHBox->addWidget(m_checkButton, 1, Qt::AlignRight);
 136         QObject::connect(m_checkButton, SIGNAL(clicked()), this, SLOT(slotCheckButtonClicked()));
 137
 138         // that the user can start typing without moving the focus
 139         numer_edit->setFocus();
 140
 141         // show the whole layout
 142         baseWidget->show();
 143
 144         // show the whole layout
 145         m_taskWidget->show();
 146         m_resultWidget->hide();
 147
 148         // add tooltip and qwhatsthis help to the widget
 149         QToolTip::add(this, i18n("In this exercise you have to solve a given task with fractions."));
 150         QWhatsThis::add(this, i18n("In this exercise you have to solve the generated task. You have to enter numerator and denominator. You can adjust the difficulty of the task with the boxes in the toolbar. Do not forget to reduce the result!"));
 151 }
 152
 153 /* destructor */
 154 TaskView::~TaskView()
 155 {
 156 #ifdef DEBUG
 157         kdDebug() << "destructor TaskView()" << endl;
 158 #endif
 159
 160         /* no need to delete any child widgets, Qt does it by itself */
 161 }
 162
 163 /** the parameters of task generation can be set with this function */
 164 void TaskView::setTaskParameters(bool padd_sub, bool pmul_div, unsigned int pnr_ratios, unsigned int pmax_md)
 165 {
 166         // at least one operation must be enabled
 167         if ((padd_sub == false) && (pmul_div == false))
 168                 padd_sub = true;
 169
 170         // we need at least 2 ratios
 171         if (pnr_ratios < 2)
 172                 pnr_ratios = 2;
 173
 174         // we can only visualize 5 ratios, so we have to limit it
 175         if (pnr_ratios > 5)
 176                 pnr_ratios = 5;
 177
 178         // the main denominator must be at least 2^pnr_ratios
 179         if (pow(2, pnr_ratios) > pmax_md)
 180                 pmax_md = (unsigned int) pow(2, pnr_ratios);
 181
 182         // so everything seems to be fine, lets set the internal values to the given
 183         // ones
 184         add_sub = padd_sub;
 185         mul_div = pmul_div;
 186         max_md = pmax_md;
 187
 188         nr_ratios = pnr_ratios;
 189
 190         return;
 191 }
 192
 193 /** resets the current state, creates a new task and count the last task as
 194  * wrong, if it wasn't solved (in _NEXT_TASK state) yet
 195  * mainly used after changing the task parameters */
 196 void TaskView::forceNewTask()
 197 {
 198 #ifdef DEBUG
 199         kdDebug() << "forceNewTask TaskView()" << endl;
 200 #endif
 201
 202         if (m_currentState == _CHECK_TASK)
 203         {
 204                 // emit the signal for wrong
 205                 signalTaskSolvedWrong();
 206         }
 207         m_currentState = _CHECK_TASK;
 208         m_checkButton->setText(i18n("&Check Task"));
 209
 210         // generate next task
 211         (void) nextTask();
 212 }
 213
 214
 215 /* ------ public slots ------ */
 216
 217 void TaskView::update()
 218 {
 219         // call update of components
 220         m_taskWidget->updateAndRepaint();
 221         m_resultWidget->updateAndRepaint();
 222
 223         // update for itself
 224         ((QWidget *) this)->update();
 225 }
 226
 227
 228 /* ------ private member functions ------ */
 229
 230 /**     - checks the entered result and compares it to the task's result
 231                 - shows the correct result and informs the user if he was right or wrong
 232                 - if the user entered the result unreduced, he will be informed about it
 233                 - if the user entered a 0 for the denominator, he will be informed about
 234                   it (division by zero)
 235                 - emits signals if task was solved right or wrong */
 236 void TaskView::showResult()
 237 {
 238         QString tmp_str; /* to build a string for a label */
 239         QPalette pal;
 240         QColorGroup cg;
 241
 242         // change the tooltip of the check button
 243         QToolTip::add(m_checkButton, i18n("Click on this button to get to the next task."));
 244
 245         numer_edit->setEnabled(false);
 246         deno_edit->setEnabled(false);
 247
 248         result = current_task.solve();
 249         m_resultWidget->setResult(result);
 250         m_resultWidget->show();
 251
 252         // an empty numerator field will be interpreted as 0
 253         if (numer_edit->text().isEmpty() == true)
 254                 numer_edit->setText("0");
 255
 256         // an empty denominator field will be interpreted as 1
 257         if (deno_edit->text().isEmpty() == true)
 258                 deno_edit->setText("1");
 259
 260         /* store the entered result to check it, but without reducing */
 261         entered_result.setNumerator(numer_edit->text().toInt(), false);
 262         entered_result.setDenominator(deno_edit->text().toInt(), false);
 263
 264         // check the entered result; 0/1 == 0/5 -> true,
 265         // but 0/1 == 0/0 -> false
 266         // a 0 for denominator is never allowed (always counted as wrong)
 267         //
 268         // we have to get the 0 directly from the input field, because
 269         // Ratio::setDenominator(0, false) will set the denominator to 1 to ensure
 270         // the Ratio is valid
 271         if ( (deno_edit->text().toInt() != 0) && ((entered_result == result) ||
 272                   (result.numerator() == 0 && entered_result.numerator() == 0)) )
 273         {
 274                 // emit the signal for correct
 275                 signalTaskSolvedCorrect();
 276
 277                 /* yes, the user entered the correct result */
 278                 result_label->setText(i18n("CORRECT"));
 279                 pal = result_label->palette(); /* set green font color */
 280                 cg = pal.active();
 281                 cg.setColor(QColorGroup::Foreground, QColor(6, 179, 0));
 282                 pal.setActive(cg);
 283                 cg = pal.inactive();
 284                 cg.setColor(QColorGroup::Foreground, QColor(6, 179, 0));
 285                 pal.setInactive(cg);
 286                 result_label->setPalette(pal);
 287                 result_label->show(); /* show the result at the end of the task */
 288         } else {
 289                 // emit the signal for wrong
 290                 signalTaskSolvedWrong();
 291
 292                 /* no, the user entered the wrong result */
 293                 result_label->setText(i18n("WRONG"));
 294                 pal = result_label->palette(); /* set red font color */
 295                 cg = pal.active();
 296                 cg.setColor(QColorGroup::Foreground, QColor(red));
 297                 pal.setActive(cg);
 298                 cg = pal.inactive();
 299                 cg.setColor(QColorGroup::Foreground, QColor(red));
 300                 pal.setInactive(cg);
 301                 result_label->setPalette(pal);
 302
 303                 result_label->show(); /* show the result at the end of the task */
 304
 305                 // if the user entered a 0 for the denominator (division by 0) we have to
 306                 // get the 0 directly from the input field, because
 307                 // Ratio::setDenominator(0, true) will set the denominator to 1 to ensure
 308                 // the Ratio is valid
 309                 if (deno_edit->text().toInt() == 0)
 310                 {
 311                         KMessageBox::information(this,
 312                                                  i18n("You entered a 0 as the denominator. This means division by zero, which is not allowed. This task will be counted as not correctly solved."));
 313                 } else {
 314                         /* maybe the entered ratio was not reduced */
 315                         entered_result.reduce();
 316                         if (entered_result == result)
 317                                 KMessageBox::information(this,
 318                                                          i18n("You entered the correct result, but not reduced.\nAlways enter your results as reduced. This task will be counted as not correctly solved."));
 319                 }
 320         } /* if (entered_result == result) */
 321 }
 322
 323 /** generate the next task and show it to the user */
 324 void TaskView::nextTask()
 325 {
 326         // change the tooltip of the check button
 327         QToolTip::add(m_checkButton, i18n("Click on this button to check your result. The button will not work if you have not entered a result yet."));
 328
 329         numer_edit->setEnabled(true);
 330         deno_edit->setEnabled(true);
 331
 332         result_label->hide(); /* do not show the result at the end of the task */
 333         m_resultWidget->hide();
 334
 335         /* clear user input */
 336         deno_edit->setText("");
 337         numer_edit->setText("");
 338         numer_edit->setFocus();
 339
 340         /* create a new task */
 341         QApplication::setOverrideCursor(waitCursor); /* show the sand clock */
 342         current_task.create_task(max_md, nr_ratios, add_sub, mul_div);
 343         QApplication::restoreOverrideCursor(); /* show the normal cursor */
 344
 345         // update the task widget
 346         m_taskWidget->setTask((const task) (current_task));
 347 }
 348
 349 /* ------ private slots ------ */
 350
 351 void TaskView::slotCheckButtonClicked()
 352 {
 353         if (m_currentState == _CHECK_TASK)
 354         {
 355                 // if nothing has been entered by the user, we don't check the result yet
 356                 if (numer_edit->text().isEmpty() == true && deno_edit->text().isEmpty() ==
 357 true)
 358                         return;
 359                 m_currentState = _NEXT_TASK;
 360                 m_checkButton->setText(i18n("N&ext Task"));
 361                 (void) showResult();
 362         } else {
 363                 m_currentState = _CHECK_TASK;
 364                 m_checkButton->setText(i18n("&Check Task"));
 365                 (void) nextTask();
 366         }
 367 }