限制父小部件中的子小部件移动范围

Question

我正在执行拖放小部件功能。我在Internet上复制了一段代码，并重写了三个类mousePressEvent，mouseReleaseEvent和mouseMoveEvent。

当子窗口小部件移动到父窗口小部件的边界时，它将覆盖父窗口小部件的边界。我不希望这样。我想保留父窗口小部件的边框。有没有办法使子窗口小部件仅在父窗口小部件的内容区域中移动？

我尝试了几种方法，但都失败了

首先：设置父控件布局的setContentsMargins属性

第二：设置父控件的填充

第三：设置子控件的边距

import sys
from PyQt4 import QtGui, QtCore
from PyQt4.QtCore import Qt, QMimeData, QDataStream, QIODevice, QByteArray, QPoint, QSize
from PyQt4.QtGui import QLabel, QWidget, QHBoxLayout, QStyleOption, QPainter, QStyle, QDrag, QListWidgetItem, QIcon, \
    QFontMetricsF, QColor


class Label(QWidget):
    def __init__(self):
        super(Label, self).__init__()

        self.setStyleSheet("""
            *{             border-width: 1px;
             border-style: solid;
             border-color: #cdcdcd;
             background-color:blue
             }
        """)
        self.setFixedSize(300, 300)

    def paintEvent(self, event):
        super(Label, self).paintEvent(event)
        opt = QStyleOption()
        opt.initFrom(self)
        painter = QPainter(self)
        painter.setRenderHint(QPainter.Antialiasing)
        self.style().drawPrimitive(QStyle.PE_Widget, opt, painter, self)

    def mousePressEvent(self, event):
        self.__mousePressPos = None
        self.__mouseMovePos = None
        if event.button() == QtCore.Qt.LeftButton:
            self.__mousePressPos = event.globalPos()
            self.__mouseMovePos = event.globalPos()

        super(Label, self).mousePressEvent(event)

    def mouseMoveEvent(self, event):
        if event.buttons() == QtCore.Qt.LeftButton:
            # adjust offset from clicked point to origin of widget
            currPos = self.mapToGlobal(self.pos())
            globalPos = event.globalPos()
            diff = globalPos - self.__mouseMovePos
            newPos = self.mapFromGlobal(currPos + diff)
            self.move(newPos)

            self.__mouseMovePos = globalPos

        super(Label, self).mouseMoveEvent(event)

    def mouseReleaseEvent(self, event):
        if self.__mousePressPos is not None:
            moved = event.globalPos() - self.__mousePressPos
            if moved.manhattanLength() > 3:
                event.ignore()
                return

        super(Label, self).mouseReleaseEvent(event)


class Widget(QWidget):
    def __init__(self):
        super(Widget, self).__init__()
        box = QHBoxLayout()
        box.setContentsMargins(20, 20, 20, 20)
        self.setLayout(box)
        box.addWidget(Label())
        self.setFixedSize(500, 500)

        self.setStyleSheet("""
            *{             border-width: 10px;
             border-style: solid;
             border-color: red;}
        """)

    def paintEvent(self, event):
        super(Widget, self).paintEvent(event)
        opt = QStyleOption()
        opt.initFrom(self)
        painter = QPainter(self)
        painter.setRenderHint(QPainter.Antialiasing)
        self.style().drawPrimitive(QStyle.PE_Widget, opt, painter, self)


class Example(QtGui.QWidget):

    def __init__(self):
        super(Example, self).__init__()

        self.initUI()

    def initUI(self):
        h = QtGui.QHBoxLayout()
        h.addWidget(Widget())
        self.setLayout(h)
        self.setGeometry(100, 100, 900, 000)
        self.setWindowTitle("PyQt")
        self.show()


def main():
    app = QtGui.QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec_())


if __name__ == '__main__':
    main()

我正在执行拖放小部件功能。我在Internet上复制了一段代码，并重写了三个类mousePressEvent，mouseReleaseEvent和mouseMoveEvent。当子窗口小部件移到...

Answer 1

父QWidget总是绘制在孩子的下方，因此您会看到这种效果。解决方案是在包含红色边框的蓝色子项之上创建另一个子项，该子项的大小与父项相同（通过布局实现）