signals and slots

[prathibha83]

Hi,
I am developing a small application to illustrate signals and slots.
the application has one button and label.
If I click on button It should change the label's text.

And my application is......


quitApp::quitApp(QWidget *parent)
: QWidget(parent)
{
//ui.setupUi(this);
QPushButton *click = new QPushButton("click me", this);
click->setGeometry(50, 40, 75, 30);
label=new QLabel("one",this);
connect(click, SIGNAL(clicked()), label, SLOT(changeText()));
QVBoxLayout* layout = new QVBoxLayout(this);
layout->addWidget(click);
layout->addWidget(label);
}
void quitApp::changeText()
{
label->setText("two");
}



Thanks,
Prathibha.

[divanov]

Setting custom geometry for button affects application look & feel.

[savaj]

Hi,
I am developing a small application to illustrate signals and slots.
the application has one button and label.
If I click on button It should change the label's text.

And my application is......


quitApp::quitApp(QWidget *parent)
: QWidget(parent)
{
//ui.setupUi(this);
QPushButton *click = new QPushButton("click me", this);
click->setGeometry(50, 40, 75, 30);
label=new QLabel("one",this);
connect(click, SIGNAL(clicked()), label, SLOT(changeText()));
QVBoxLayout* layout = new QVBoxLayout(this);
layout->addWidget(click);
layout->addWidget(label);
}
void quitApp::changeText()
{
label->setText("two");
}



Thanks,
Prathibha.

I didan't get you exactly. What is the exact problem?? Search wiki to get example that show use of signals and slots.

[danhicksbyron]

It's always good practice to capture the return code from "connect" and test it with an assert. Eg:

bool rc = connect(click, SIGNAL(....
Q_ASSERT(rc);
Q_UNUSED(rc);

(The Q_UNUSED prevents the compiler from complaining about unused variables when you compile with assertion checks turned off.)

Doing this check can help detect a lot of irritating errors in signal syntax.