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Update a Qt SLOT

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  • R Offline
    R Offline
    Rajni
    wrote on 2 Jun 2016, 04:46 last edited by
    #3

    ThankYou Jsulm, for your quick reply.

    I am doing the same as you suggested but it doesn't work.
    At run time when i am changing the value of spinbox it will not showing any changes in value .```
    as shown below in code flag is a variable where i want to store the value of qspinbox and switch that value in function fuelbar() to show some images.

    //your code here

    #include "widget.h"
#include "ui_widget.h"
#include<QtTest/QTest>
#include<QDebug>
#include<QSerialPortInfo>

int flag ;

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

   connect(ui->FuelspinBox, SIGNAL(valueChanged(int)),this, SLOT(on_FuelspinBox_valueChanged(int)));
fuelbar();
}
void Widget:: fuelbar()
{
       ui->bar2->setVisible(false);
    ui->bar3->setVisible(false);
    ui->bar4->setVisible(false);
    ui->bar5->setVisible(false);
    ui->bar6->setVisible(false);
    ui->bar7->setVisible(false);
    ui->bar8->setVisible(false);
    ui->bar9->setVisible(false);
    ui->bar10->setVisible(false);
   // qDebug()<<"flag in fuelbar"<<flag;
    switch (flag)
    {

    case 0:

        ui->bar1->setVisible(true);
        ui->led->setVisible(true);
        ui->FuelIcon->setVisible(true);
       // lit=false;
        timer1s->start(1000);
        connect(timer1s,SIGNAL(timeout()),this,SLOT(barOFF()));
        break;

    case 1:
        ui->bar1->setVisible(true);
        ui->bar2->setVisible(true);
        ui->led->setVisible(false);
         ui->FuelIcon->setVisible(true);
        timer1s->start(1000);
        connect(timer1s,SIGNAL(timeout()),this,SLOT(bar2OFF()));
        break;

    case 2:
        ui->bar1->setVisible(true);
        ui->bar2->setVisible(true);
        ui->bar3->setVisible(true);
        ui->led->setVisible(false);

        break;

    case 3:
        ui->bar1->setVisible(true);
        ui->bar2->setVisible(true);
        ui->bar3->setVisible(true);
        ui->bar4->setVisible(true);
        ui->led->setVisible(false);
        break;

    case 4:
        ui->bar1->setVisible(true);
        ui->bar2->setVisible(true);
        ui->bar3->setVisible(true);
        ui->bar4->setVisible(true);
        ui->bar5->setVisible(true);
        ui->led->setVisible(false);
        break;

    case 5:
        ui->bar1->setVisible(true);
        ui->bar2->setVisible(true);
        ui->bar3->setVisible(true);
        ui->bar4->setVisible(true);
        ui->bar5->setVisible(true);
        ui->bar6->setVisible(true);
        ui->led->setVisible(false);
        break;

    case 6:
        ui->bar1->setVisible(true);
        ui->bar2->setVisible(true);
        ui->bar3->setVisible(true);
        ui->bar4->setVisible(true);
        ui->bar5->setVisible(true);
        ui->bar6->setVisible(true);
        ui->bar7->setVisible(true);
        ui->led->setVisible(false);
        break;

    case 7:
        ui->bar1->setVisible(true);
        ui->bar2->setVisible(true);
        ui->bar3->setVisible(true);
        ui->bar4->setVisible(true);
        ui->bar5->setVisible(true);
        ui->bar6->setVisible(true);
        ui->bar7->setVisible(true);
        ui->bar8->setVisible(true);
        ui->led->setVisible(false);
        break;

    case 8:
        ui->bar1->setVisible(true);
        ui->bar2->setVisible(true);
        ui->bar3->setVisible(true);
        ui->bar4->setVisible(true);
        ui->bar5->setVisible(true);
        ui->bar6->setVisible(true);
        ui->bar7->setVisible(true);
        ui->bar8->setVisible(true);
        ui->bar9->setVisible(true);
        ui->led->setVisible(false);
        break;

    case 9:
        ui->bar1->setVisible(true);
        ui->bar2->setVisible(true);
        ui->bar3->setVisible(true);
        ui->bar4->setVisible(true);
        ui->bar5->setVisible(true);
        ui->bar6->setVisible(true);
        ui->bar7->setVisible(true);
        ui->bar8->setVisible(true);
        ui->bar9->setVisible(true);
        ui->bar10->setVisible(true);
        ui->led->setVisible(false);
      break;
    }
}

void Widget::on_FuelspinBox_valueChanged(int arg1)
{
   flag=arg1;
  // flag=ui->FuelspinBox->value();
   qDebug()<<"flag"<<flag;
   update();
}
    1 Reply Last reply
    0
    • J Offline
      J Offline
      jsulm
      Lifetime Qt Champion
      wrote on 2 Jun 2016, 08:18 last edited by jsulm 6 Feb 2016, 08:21
      #4

      Make sure your connect was successful:

      qDebug() << connect(ui->FuelspinBox, SIGNAL(valueChanged(int)),this, SLOT(on_FuelspinBox_valueChanged(int)));

      this should print true.

      Is on_FuelspinBox_valueChanged(int) declared as slot?
      Another thing to check: in on_FuelspinBox_valueChanged(int) you do not call fuelbar()! So a new flag value will not change anything! You have to call fuelbar() in on_FuelspinBox_valueChanged(int).
      Does

      qDebug()<<"flag"<<flag;

      print something? You can place a break point there to see whether it is called.

      https://forum.qt.io/topic/113070/qt-code-of-conduct

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      0
      • J Offline
        J Offline
        jsulm
        Lifetime Qt Champion
        wrote on 2 Jun 2016, 08:28 last edited by
        #5

        One more thing: your flag is not initialized! It could contain any number. You should assign it a value. And it would be better to put it in your Widget class as private property and initialize it in constructor.

        https://forum.qt.io/topic/113070/qt-code-of-conduct

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        0
        • R Offline
          R Offline
          Rajni
          wrote on 2 Jun 2016, 08:52 last edited by
          #6

          Thanks again Jsulm ..:)

          yes I have put on_FuelspinBox_valueChanged(int) in SLOT.

          when I call fuelbar() in on_FuelspinBox_valueChanged(int) flag value changes and it shows the respective images but in case when flag value is 0 and 1 where i have to toggle image and i am using 1 sec timer for that is misbehaving it blinks for all the cases.

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          0
          • R Offline
            R Offline
            Rajni
            wrote on 2 Jun 2016, 08:59 last edited by
            #7

            and I have to transmit that updated value of flag in serial port so do i have also write on on_FuelspinBox_valueChanged(int) .

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            0
            • R Offline
              R Offline
              Rajni
              wrote on 3 Jun 2016, 03:22 last edited by
              #8

              please help me......

              1 Reply Last reply
              0
              • J Offline
                J Offline
                jsulm
                Lifetime Qt Champion
                wrote on 3 Jun 2016, 04:17 last edited by
                #9

                What do you mean by "that is misbehaving it blinks for all the cases"?
                One thing I see is: you connect the timeout() signal each time case 0 or 1 is executed!
                You should do it once (preferably in the constructor).
                What does barOFF() do?

                https://forum.qt.io/topic/113070/qt-code-of-conduct

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                • R Offline
                  R Offline
                  Rajni
                  wrote on 3 Jun 2016, 04:41 last edited by
                  #10

                  I want to to toggle the image if flag is 0 and 1, but if i am calling fuelbar() in on_FuelspinBox_valueChanged(int) then the both image are toggling for all the case either the flag is value is 2 to 9.I have include the code below may be this will help you to understand .

                  Please give me some solution how can i handle it.
                  Thankyou..:)

                  void Widget:: barOFF()
                  {

                   ui->bar1->setVisible(false);
 ui->led->setVisible(false);
  ui->FuelIcon->setVisible(false);
 timer1s->stop();
 QTest::qWait(500);
 timer1s->start(500);
 connect(timer1s,SIGNAL(timeout()),this,SLOT(barON()));

                  }

                  void Widget:: barON()
                  {
                  ;
                  ui->bar1->setVisible(true);
                  ui->led->setVisible(true);
                  ui->FuelIcon->setVisible(true);
                  timer1s->stop();
                  QTest::qWait(500);
                  timer1s->start(500);
                  connect(timer1s,SIGNAL(timeout()),this,SLOT(barOFF()));

                  }
                  void Widget:: bar2OFF()
                  {
                  ui->bar1->setVisible(false);
                  ui->bar2->setVisible(false);
                  ui->led->setVisible(false);
                  ui->FuelIcon->setVisible(false);
                  timer1s->stop();
                  QTest::qWait(500);
                  timer1s->start(500);
                  connect(timer1s,SIGNAL(timeout()),this,SLOT(bar2ON()));

                  }

                  void Widget:: bar2ON()
                  {
                  ui->bar1->setVisible(true);
                  ui->bar2->setVisible(true);
                  ui->led->setVisible(false);
                  ui->FuelIcon->setVisible(true);
                  timer1s->stop();
                  QTest::qWait(500);
                  timer1s->start(500);
                  connect(timer1s,SIGNAL(timeout()),this,SLOT(bar2OFF()));

                  }

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                  • E Offline
                    E Offline
                    euchkatzl
                    wrote on 3 Jun 2016, 07:58 last edited by euchkatzl 6 Mar 2016, 07:59
                    #11

                    as @jsulm said :

                    put these lines :

                    connect(timer1s,SIGNAL(timeout()),this,SLOT(bar2OFF()));
connect(timer1s,SIGNAL(timeout()),this,SLOT(barON()));

                    in your constructor because you should do that only once !!! When you call connect multiple times then your slot get called as often as your code executes the lines above !

                    For your approach is ist better not to use a single Timer because you have to call different slots !

                    Take a look at QTimer single shot function ! That ist a static function so you dont need a QTimer object :
                    http://doc.qt.io/qt-5/qtimer.html#singleShot

                    as a example for your code

                    void Widget:: barOFF()
{

 ui->bar1->setVisible(false);
 ui->led->setVisible(false);
  ui->FuelIcon->setVisible(false);
// timer1s->stop(); --> not needed anymore
 QTest::qWait(500);
// timer1s->start(500);
 //connect(timer1s,SIGNAL(timeout()),this,SLOT(barON()));
QTimer::singleShot(500,this,SLOT(barON()));
}
                    1 Reply Last reply
                    2
                    • S Offline
                      S Offline
                      SGaist
                      Lifetime Qt Champion
                      wrote on 3 Jun 2016, 21:56 last edited by
                      #12

                      Hi,

                      Important side note: Don't ever use QTest in production code. Like the name of the module suggests, it's only to be used for writing unit tests.

                      Interested in AI ? www.idiap.ch
                      Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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                      0

                      12/12

                      3 Jun 2016, 21:56

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