Question

尝试为包含像素图的小部件添加滚动条，但看不到滚动条。

这是我的代码：-

import sys
from PyQt4 import QtGui, QtCore, Qt

class Canvas(QtGui.QWidget):
    def __init__(self, *args, **kwargs):
        super(Canvas, self).__init__()
        self.pixmap = QtGui.QPixmap()

    def paintEvent(self, event):
        print 'paintevent'
        painter = QtGui.QPainter(self)
#         painter.scale(3,3)
#         painter.translate(200, 200)
        painter.drawPixmap(QtCore.QPoint(), self.pixmap)

class Window(QtGui.QMainWindow):

    def __init__(self):
        super(Window, self).__init__()
        self.setGeometry(50, 50, 500, 300)
        self.setWindowTitle("PyQT tuts!")
        self.setWindowIcon(QtGui.QIcon('pythonlogo.png'))
        openFile = QtGui.QAction("Open File", self)
        openFile.setShortcut("Ctrl+O")
        openFile.setStatusTip('Open File')
        openFile.triggered.connect(self.file_open)
        zoomIn = QtGui.QAction("Zoom", self)
        zoomIn.setShortcut("Ctrl+z")
        zoomIn.setStatusTip('Open File')
        zoomIn.triggered.connect(self.zoom_in)
        self.scrollArea = QtGui.QScrollArea()
        self.scrollBars = {
            QtCore.Qt.Vertical: self.scrollArea.verticalScrollBar(),
            QtCore.Qt.Horizontal: self.scrollArea.horizontalScrollBar(),
        }
        self.statusBar()
        mainMenu = self.menuBar()

        fileMenu = mainMenu.addMenu('&File')
        fileMenu.addAction(openFile)
        fileMenu.addAction(zoomIn)
        self.canvas = Canvas()
        self.scrollArea.setWidget(self.canvas)
        self.scrollArea.setWidgetResizable(True)
        self.setCentralWidget(self.scrollArea)
        self.home()
        self.resize(200, 200)

    def home(self):
        self.show()

    def file_open(self):
        name = QtGui.QFileDialog.getOpenFileName(self, 'Open File')
        file = open(name,'r')
        with file:
            imageData = file.read()        
            image = QtGui.QImage.fromData(imageData)
            print(image.isNull())
            self.load_pixmap(image)

    def load_pixmap(self, image):
        self.canvas.pixmap = QtGui.QPixmap.fromImage(image)

    def zoom_in(self):
        print 'zoom in'
        self.canvas.update()
        print self.scrollArea
        print self.scrollBars[QtCore.Qt.Horizontal].value()
        self.scrollBars[QtCore.Qt.Horizontal].setValue(10)
        print self.scrollBars[QtCore.Qt.Horizontal].value()
        print self.scrollArea.horizontalScrollBarPolicy()

def run():
    app = QtGui.QApplication(sys.argv)
    GUI = Window()
    sys.exit(app.exec_())

run()

Answer 1

此链接将非常有用：http://doc.qt.io/archives/qt-4.8/qscrollarea.html

我的建议是：默认情况下，在滚动区域中，滚动条仅在需要时显示。您是否尝试将滚动条策略设置为Qt.ScrollBarAlwaysOn？

pyqt4滚动条不可见

1 个答案: