通过制作简单的图片查看器PyQ学习

Question

我有一个方法检测按键事件，然后想调用对话框检索一个文件（稍后添加其他选项显示某些文件或全部）

但我必须去我的根使一些物体像全球

pic_as_label = QLabel(self)

请随便指出其他的问题。这是工作，虽然我知道全球是坏形式

import sys, os

from PyQt5.QtWidgets import QApplication, QWidget, QLabel, QDesktopWidget, QFileDialog, QAction, QTextEdit
from PyQt5.QtGui import QIcon, QPixmap
from PyQt5.QtCore import Qt

class App(QWidget):

    def __init__(self):
        super().__init__()
        self.title = 'Image Viewer'
        self.left = 10
        self.top = 10
        self.width = 640
        self.height = 480
        self.initUI()

    def openFileNameDialog(self):
        self.textEdit = QTextEdit()
        self.setCentralWidget(self.textEdit)
        self.statusBar()

        openFile = QAction(QIcon('open.png'), 'Open', self)
        openFile.setShortcut('Ctrl+O')
        openFile.setStatusTip('Open new File')
        openFile.triggered.connect(self.showDialog)

        menubar = self.menuBar()
        fileMenu = menubar.addMenu('&File')
        fileMenu.addAction(openFile)       

        self.setGeometry(300, 300, 350, 300)
        self.setWindowTitle('File dialog')
        self.show()

    def initUI(self):
        global desktop
        global ScrWidth
        global ScrHeight
        global pic_as_label

        desktop = os.environ['USERPROFILE'] + '\Desktop'
        self.setWindowTitle(self.title)
        self.setGeometry(self.left, self.top, self.width, self.height)
        self.setAutoFillBackground


        ScrWidth=QDesktopWidget().availableGeometry().width()
        ScrHeight=QDesktopWidget().availableGeometry().height()    

        #pallete color Black
        p = self.palette()
        p.setColor(self.backgroundRole(), Qt.black)
        self.setPalette(p)
        self.resize(ScrWidth, ScrHeight)

        pic_as_label = QLabel(self)
        pixmap = QPixmap("image.jpg")

        pixmap = pixmap.scaled (ScrWidth, ScrHeight, Qt.KeepAspectRatio, transformMode=Qt.SmoothTransformation)
        pic_as_label.move(((ScrWidth-pixmap.width())/2), ((ScrHeight-pixmap.height())/2))
        pic_as_label.setPixmap(pixmap)
        self.show()

    def get_pic_name(self):
        #Open File dialogue
        fname = (QFileDialog.getOpenFileName(self, 'Open file',desktop, 'Images (*.jpg)'))[0]
        App.setWindowTitle(self, os.path.split(fname)[1])
        return fname

    def display_photo(self, fname,w,h):
        pixmap = QPixmap(fname)
        pixmap = pixmap.scaled (w, h, Qt.KeepAspectRatio, transformMode=Qt.SmoothTransformation)
        pic_as_label.move(((w-pixmap.width())/2), ((h-pixmap.height())/2))
        pic_as_label.setPixmap(pixmap)



    def keyPressEvent(self,k):
        if k.key() == Qt.Key_O:
            fname = App.get_pic_name(self)
            if fname:
                picture_dir=os.path.split(fname)[0]
                App.setWindowTitle(self, picture_dir)
                App.display_photo(self,fname,ScrWidth, ScrHeight)
        if k.key() == Qt.Key_X:
            sys.exit(0)

if __name__ == '__main__': 
    app = QApplication(sys.argv)
    ex = App()
    sys.exit(app.exec_())