PyQt5 setLayout函数导致程序崩溃

Question

我正在使用Mark Summerfield的Rapid GUI编程书，该书是为PyQt4编写的，我正在使用PyQt5。有些事情肯定不一样。

有人能理解为什么这在我运行Ubuntu 13.04的Linux机器上失败吗？它在Mint 15上运行，但有时会以分段错误结束。我认为这与PyQt4和PyQt5之间的差异有关，我一直在qt-project.org网站上研究C++的实现。到目前为止，我可以看出QVBoxLayout确实继承了QDialog，并且它确实有一个setLayout函数。但是，注释掉_init_函数中的最后一行将允许程序在不崩溃的情况下运行，但也不会在QDialog框中添加任何小部件。

import sys
import PyQt5.QtCore
import PyQt5.QtGui
import PyQt5.QtWidgets
class Form(PyQt5.QtWidgets.QDialog):
    def __init__(self, parent=None):
        super(Form, self).__init__(parent)
        self.browser = PyQt5.QtWidgets.QTextBrowser()
        self.lineEdit = PyQt5.QtWidgets.QLineEdit("default statement here")
        self.lineEdit.selectAll()
        layout = PyQt5.QtWidgets.QVBoxLayout()
        layout.addWidget(self.browser)
        layout.addWidget(self.lineEdit)
        self.setLayout(layout)    # <--- program seems to crash here

app = PyQt5.QtWidgets.QApplication(sys.argv)
form = Form()
form.show()
app.exec_()

我收到一条初始错误消息，重复了大约10次：

(python3:9896): Gtk-CRITICAL **: IA__gtk_widget_style_get: assertion `GTK_IS_WIDGET (widget)' failed

然后是下面的块，它重复直到我杀死程序：

QXcbShmImage: shmget() failed (22) for size -524284 (65535x65535)
QWidget::paintEngine: Should no longer be called
QPainter::begin: Paint device returned engine == 0, type: 1
QWidget::paintEngine: Should no longer be called
QPainter::begin: Paint device returned engine == 0, type: 1
QPainter::translate: Painter not active
QPainter::save: Painter not active
QPainter::setClipRect: Painter not active
QPainter::pen: Painter not active
QPainter::setPen: Painter not active
QPainter::pen: Painter not active
QPainter::setPen: Painter not active
QPainter::restore: Unbalanced save/restore
QWidget::paintEngine: Should no longer be called
QPainter::begin: Paint device returned engine == 0, type: 1
QPainter::setClipRect: Painter not active
[etc, etc, etc...]

Answer 1

问题在于QTextBrowser的大小。

看到这个错误：

https://bugreports.qt-project.org/browse/QTBUG-32527