Torben at 20:21, 30 October 2024

2024-10-30T20:21:55Z

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[[Category:Coding]][[Category:Python]]
see [http://www.commandprompt.com/community/pyqt/]
==Basic Application==
import sys
from PyQt4 import QtGui
from PyQt4.QtCore import SIGNAL
from Ui_gui import Ui_MainWindow # load my QT Window ui, created by QT4-Designer + pyuic4

class MainWindowGUI(QtGui.QMainWindow, Ui_ofetGUI):
def __init__(self, parent=None):
QtGui.QMainWindow.__init__(self, parent)
self.setupUi(self)

# connect qt-signals to functions
self.connect(self.ButtonStart,SIGNAL("clicked()"),self.clickedButtonStart) # ButtonStart is a name given by me

def closeEvent(self, event): # define what to do when closing the window (e.g. via X-Button)
""

def clickedButtonStart(self):
""

if __name__ == "__main__": # ============= Starting Point
app = QtGui.QApplication(sys.argv)
mainWindow = MainWindowGUI()
mainWindow.show()
sys.exit(app.exec_())

==Widgets==
====QPushButton====
=std. Buttons
setEnabled(True)
setEnabled(False)
Signal: "clicked()"

====QCheckBox====
setCheckState ( int )
int checkState () == 2 : # 0=unchecked, 1=partly, 2=checked

====QSpinBox====
enter int numbers
setValue( int )
int value()

====QDoubleSpinBox====
enter float numbers
setValue( float )
float value()
Signal: "valueChanged()"

====QLineEdit====
1-line textfield
QString text ()
setText ( String )

====QLCDNumber====
display(int)
display(float)

====QProcessBar====
int value () const
void setValue ( int value )

int minimum () const
void setMinimum ( int minimum )

int maximum () const
void setMaximum ( int maximum )

====QLabel====
setText( String )

====QTableWidget====
row = rowCount ()
insertRow(row)
while self.Table.rowCount () > 0:
self.Table.removeRow(0)

tItem = QtGui.QTableWidgetItem()
tItem.setText( str( round(tA, 1) ))
#tItem.setBackground (QtGui.QColor("green"))
setItem(row,column,tItem)
# disable editing of table
self.Table.setEditTriggers(QAbstractItemView.NoEditTriggers)

====QMessageBox====
if ( os.path.isfile( file ) ):
reply = QMessageBox.warning(self, # choose: (warning, about, critical, question)
"Output file already exists!", # title
"Overwrite the file " + file + " ?", # message text
QMessageBox.Yes|QMessageBox.No # choose: (Yes, No, Cancel, Ok)
)
if reply != QMessageBox.Yes : # if not "Yes" cancel here
return

====File Dialog====
myFileDialog = QtGui.QFileDialog(self)
dirname = str ( myFileDialog.getExistingDirectory(self, 'Open dir', myVarStartDir) )

==Signals==
QObject.connect(self.ButtonStart, SIGNAL("clicked()"),self.myFunction)

# QThread notifies main gui:
self.emit(SIGNAL("MoinMoin"))
# gui:
QObject.connect(self.thread, SIGNAL("MoinMoin"), self.myFunction)

# QThread sends values to main gui
# in Thread
self.emit(SIGNAL("temperatureChanged(PyQt_PyObject)"),[self.t1, self.t2])
# main gui:
QObject.connect(self.thread, SIGNAL("temperatureChanged(PyQt_PyObject)"), self.temperatureChanged)
# ...
def temperatureChanged(self, temps):
self.lcdTemp1.display(temps[0])
self.lcdTemp2.display(temps[1])

==Threads==
===Main File===
# import my thread class MeasuringThread from file MeasuringThread
from MeasuringThread import MeasuringThread

self.thread = MeasuringThread(self) # give mainwindow as parameter to thread in order do be able to run its methods
self.connect(self.thread,SIGNAL("myUpdateSignal"),self.updateCalled)

def updateCalled(self)
""

Now the thread can be started and stopped via
self.thread.start()
self.thread.stop()

===Thread File===
from PyQt4.QtCore import SIGNAL, QThread

class MeasuringThread(QThread):
# A thread is started by calling QThread.start() never by calling run() directly!
def __init__(self, mainwindowUebergabe, parent = None):
QThread.__init__(self, parent)
self.MainWindow = mainwindowUebergabe
self.exiting = False # custum variable that is used to stop the thread

def stop(self):
self.exiting = True
self.wait() # waits until run stops on his own

def run(self):
self.exiting = False
while self.exiting == False :
""
self.emit(SIGNAL("myUpdateSignal")) # send a signal to the main window
# exit position of run function of thread. if exiting == true we end up here
""

Python - QT - Revision history

Torben at 20:21, 30 October 2024