如何在QGIS插件中从1打印到10？ （不是一次）

Question

for i in range(1, 10):
    QgsMessageLog.logMessage(str(i), tag="Validating", level=QgsMessageLog.INFO)
    time.sleep(1)

QGIS will wait for the plugin to finish. ( 123456789 )

It is bring to me result after finished work.

So i can't see step by step logging at QGIS. ( 1... 2... 3... 4... ... 9 )

I would like to see it printed each time it is executed.

How can i do that?

Answer 1

Never use time.sleep() in the main thread of the GUI, that function is block the execution of the GUI so you get that behavior, in your particular case you can use QTimeLine :

def onframeChanged(val):
    msg = str(val)
    QgsMessageLog.logMessage(msg, tag="Validating", level=QgsMessageLog.INFO)

n = 9
self.timeline = QtCore.QTimeLine(n*1000)
self.timeline.setFrameRange(0, n)
self.timeline.frameChanged.connect(onframeChanged)
self.timeline.finished.connect(self.timeline.deleteLater)
self.timeline.start()

---

If you want the task to run periodically you can use QTimer :

def onTimeout():
    msg = QtCore.QDateTime.currentDateTime().toString()
    QgsMessageLog.logMessage(msg, tag="Validating", level=QgsMessageLog.INFO)

self.timer = QtCore.QTimer(interval=1000)
self.timer.timeout.connect(onTimeout)

self.timer.start()