Led widget how to setTitle

[qtlearner123]

Hi all,

i have downloaded the source code for LED program from Qt applications website. i was successful in using the Led i was able to change the color to red, green etc. Now my main problem is i have created 20 similar Led's and i want to give some title to each led like led1, led2 etc to recognize which is ON or OFF, but i am not able to do it using setTitle function. could somebody please help me how to modify the program to give the title to each led. i am very much new to QT and i do not how to do it. i have been struggling to do this for the past several weeks, but not successful.

Thanks in advance for any support,

regards,
Satya

[ChrisW67]

QLabel and a layout of some sort.

Unless you want to tell us exactly what you downloaded, where from, and what you have done with it there is little chance of more specific answers.

[qtlearner123]

sorry for the incomplete information this is the path from which i have downloaded the source code from the following link http://qt-apps.org/content/download....1&tan=36155544. In the downloaded folder i used led related files into my project which i have attached in the present reply. Currently i am facing the problem of setting the text. please guide me or please send me the modified code so that i can set the text of led which i plan to implement like [code]Led *led1 = new Led("LED1")[\code]. (First time i am using BB code as i got warning last time. please correct me if i have not properly used it).

thanks in advance,
regards,
satya

[qtlearner123]

Hi all,

Could somebody please suggest me how to solve the above problem?

thanks and regards,
Satya

[ChrisW67]

You already have it.

The LED widget you are using does not have a facility to label itself. You have to label it separately, which is why I suggested a QLabel and layout above.

[qtlearner123]

Thank you for the help. yeah some how i managed to do it with QLabel and gridlayout but i could not get confidence on what i am doing, but is it possible for me to implement Led to label itself. i tried using QProperty but was not successful. Also i tried to qlabel with absolute positioning and led with grid layout but the absolute positioning does not seem to work as it always positions at a fixed position even if i change the position using setGeometry().

thanks and regards,
satya

[ChrisW67]

but is it possible for me to implement Led to label itself

Yes, you would have to modify the LED API to give you a label getter/setter, some good size hinting, and the paintEvent() to render the text in the relevant location with respect to the LED graphic. It would be easier to leave the LED code alone and create your own composite widget class with a layout containing a label and LED. The composite class should expose a way to set the label text, perhaps through the constructor, and LED colour/state. This is very basic C++ and Qt.

i tried to qlabel with absolute positioning and led with grid layout but the absolute positioning does not seem to work as it always positions at a fixed position even if i change the position using setGeometry().

The point of layouts is that you do not worry about positioning... that's the job of the layout using the constraints and content you give it.

Something like this (untested):

class MyLED: public QWidget {
  Q_OBJECT
public:
  MyLED(QWidget *p = 0): QWidget(p) {
    m_LED = new LED(this);
    m_label = new QLabel(this);
    VBoxLayout *layout = new QVBoxLayout;
    layout->addWidget(m_led);
    layout->addWidget(m_label);
    // tweak layout constraints as required
    setLayout(layout);
  }
  void setText(const QString &text) { m_label->setText(text); }
  void setLEDColour(...) { } 
  void setLEDState(...) { } 
 
private:
  LED *m_led;
  QLabel *m_label;
};

class MyLED: public QWidget {
  Q_OBJECT
public:
  MyLED(QWidget *p = 0): QWidget(p) {
    m_LED = new LED(this);
    m_label = new QLabel(this);
    VBoxLayout *layout = new QVBoxLayout;
    layout->addWidget(m_led);
    layout->addWidget(m_label);
    // tweak layout constraints as required
    setLayout(layout);
  }
  void setText(const QString &text) { m_label->setText(text); }
  void setLEDColour(...) { } 
  void setLEDState(...) { } 

private:
  LED *m_led;
  QLabel *m_label;
};

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