QFileDialog预览

Question

我试图让 Qt5 QFileDialog 在选择打开图像时显示图像预览。

方法 1：扩展 QFileDialog
我使用了该对话框的实现，它与 Qt 5.6.1 一起使用。

现在我使用 Qt 5.9.2，它不再工作，给出以下错误：

Traceback (most recent call last):
  File "main.py", line 74, in mouseDoubleClickEvent
    self.openFileDialog()
  File "main.py", line 123, in openFileDialog
    openDialog = QFileDialogPreview(self, 'Open file', './', self.getDialogFilter())
  File "QFileDialogPreview.py", line 22, in __init__
    self.layout().addLayout(box, 1, 3, 1, 1)
TypeError: addLayout(self, QLayout, stretch: int = 0): too many arguments

这是翻译后的类。我正在使用Python 3.5.2：

from PyQt5.QtWidgets import QFileDialog, QLabel, QVBoxLayout
from PyQt5.QtGui import QPixmap
from PyQt5.QtCore import Qt

class QFileDialogPreview(QFileDialog):
    def __init__(self, parent, caption, direcotry, filter):
        super().__init__(parent, caption, direcotry, filter)

        self.setObjectName("FileDialogPreview")
        box = QVBoxLayout(self)

        self.setFixedSize(self.width() + 250, self.height())

        self.mpPreview = QLabel("Preview", self)
        self.mpPreview.setFixedSize(250, 250)
        self.mpPreview.setAlignment(Qt.AlignCenter)
        self.mpPreview.setObjectName("labelPreview")
        box.addWidget(self.mpPreview)

        box.addStretch()

        self.layout().addLayout(box, 1, 3, 1, 1)

        self.currentChanged.connect(self.onChange)
        self.fileSelected.connect(self.onFileSelected)
        self.filesSelected.connect(self.onFilesSelected)

        self._fileSelected = None
        self._filesSelected = None

    def onChange(self, path):
        pixmap = QPixmap(path)

        if(pixmap.isNull()):
            self.mpPreview.setText("Preview")
        else:
            self.mpPreview.setPixmap(pixmap.scaled(self.mpPreview.width(), self.mpPreview.height(), Qt.KeepAspectRatio, Qt.SmoothTransformation))

    def onFileSelected(self, file):
        self._fileSelected = file

    def onFilesSelected(self, files):
        self._filesSelected = files

    def getFileSelected(self):
        return self._fileSelected

    def getFilesSelected(self):
        return self._filesSelected

方法2：单独窗口预览

我还尝试添加一个单独的预览窗口。虽然它在 QFileDialog 中选择时显示图像，但我无法将其附加到对话框本身的一侧。
我无法使用dialog.gemoetry() 上的mapToGlobal 方法获取映射到全局屏幕坐标的对话框的位置。在本例中，我得到的只是一个包含位置 0,0 且大小不匹配 100x30 的 QRect，而对话框的大小约为 800x600，大致为 2000、500。

Answer 1

当你 put 时box = QVBoxLayout(self)，你正在放置一个新的布局，你必须做的是使用自己的 Qt，为此，除了从 box 语句中删除 self 之外，QFileDialog我们还启用该标志：DontUseNativeDialog

class QFileDialogPreview(QFileDialog):
    def __init__(self, *args, **kwargs):
        QFileDialog.__init__(self, *args, **kwargs)
        self.setOption(QFileDialog.DontUseNativeDialog, True)

        box = QVBoxLayout()

        self.setFixedSize(self.width() + 250, self.height())

        self.mpPreview = QLabel("Preview", self)
        self.mpPreview.setFixedSize(250, 250)
        self.mpPreview.setAlignment(Qt.AlignCenter)
        self.mpPreview.setObjectName("labelPreview")
        box.addWidget(self.mpPreview)

        box.addStretch()

        self.layout().addLayout(box, 1, 3, 1, 1)

        self.currentChanged.connect(self.onChange)
        self.fileSelected.connect(self.onFileSelected)
        self.filesSelected.connect(self.onFilesSelected)

        self._fileSelected = None
        self._filesSelected = None

    def onChange(self, path):
        pixmap = QPixmap(path)

        if(pixmap.isNull()):
            self.mpPreview.setText("Preview")
        else:
            self.mpPreview.setPixmap(pixmap.scaled(self.mpPreview.width(), self.mpPreview.height(), Qt.KeepAspectRatio, Qt.SmoothTransformation))

    def onFileSelected(self, file):
        self._fileSelected = file

    def onFilesSelected(self, files):
        self._filesSelected = files

    def getFileSelected(self):
        return self._fileSelected

    def getFilesSelected(self):
        return self._filesSelected

输出：