問題描述

我有以下代碼來創建一個 QTreeWidget 和一個包含 2 個操作的上下文菜單.

I have the following code to create a QTreeWidget and a contextmenu with 2 actions.

import sys
from PyQt5 import QtCore, QtWidgets

class Dialog(QtWidgets.QDialog):
    def __init__(self, parent=None):
        super(Dialog, self).__init__()

        self.tw = QtWidgets.QTreeWidget()
        self.tw.setHeaderLabels(['Name', 'Cost ($)'])
        cg = QtWidgets.QTreeWidgetItem(['carrots', '0.99'])
        c1 = QtWidgets.QTreeWidgetItem(['carrot', '0.33'])
        self.tw.addTopLevelItem(cg)
        self.tw.addTopLevelItem(c1)
        self.tw.installEventFilter(self)
        layout = QtWidgets.QVBoxLayout(self)
        layout.addWidget(self.tw)

    def eventFilter(self, source: QtWidgets.QTreeWidget, event):
        if (event.type() == QtCore.QEvent.ContextMenu and
            source is self.tw):
            menu = QtWidgets.QMenu()
            AAction = QtWidgets.QAction("AAAAA")
            AAction.triggered.connect(lambda :self.a(source.itemAt(event.pos())))
            BAction = QtWidgets.QAction("BBBBBB")
            BAction.triggered.connect(lambda :self.b(source, event))
            menu.addAction(AAction)
            menu.addAction(BAction)
            menu.exec_(event.globalPos())
            return True
        return super(Dialog, self).eventFilter(source, event)

    def a(self, item):
        if item is None:
            return
        print("A: {}".format([item.text(i) for i in range(self.tw.columnCount())]))
    def b(self, source, event):
        item = source.itemAt(event.pos())
        if item is None:
            return
        print("B: {}".format([item.text(i) for i in range(source.columnCount())]))

if __name__ == '__main__':
    app = QtWidgets.QApplication(sys.argv)
    window = Dialog()
    window.setGeometry(600, 100, 300, 200)
    window.show()
    sys.exit(app.exec_())

當打開標題中的上下文菜單并單擊其中一個操作時，它會打印胡蘿卜或胡蘿卜，具體取決于我在上下文菜單中單擊的位置.但是我把右鍵事件的位置給了函數.

When opening the contextmenu in the header and clicking on one of the actions it prints either carrot or carrots, depending on where in the contextmenu I click. But I give the position of right click event to the functions.

那么為什么會發生這種情況，我該怎么做才能阻止它?

So why is this happening and what can I do to stop it?

推薦答案

你的代碼有2個錯誤:

• 主要錯誤是 itemAt() 方法使用相對于 viewport() 的坐標，而不是相對于視圖(QTreeWidget)，所以你會得到不正確的項目(標題占用空間相對于 QTreeWidget 和 viewport() 的位置有一個偏移量).

• The main error is that the itemAt() method uses the coordinates with respect to the viewport() and not with respect to the view (the QTreeWidget) so you will get incorrect items (the header occupies a space making the positions with respect to the QTreeWidget and the viewport() have an offset).

你不應該阻塞事件循環，例如阻塞 eventFilter 你可能阻塞了其他會導致難以調試的錯誤的事件，在這種情況下最好使用信號.

You should not block the eventloop, for example blocking the eventFilter you may be blocking other events that would cause errors that are difficult to debug, in this case it is better to use a signal.

class Dialog(QtWidgets.QDialog):
    rightClicked = QtCore.pyqtSignal(QtCore.QPoint)

    def __init__(self, parent=None):
        super(Dialog, self).__init__()

        self.tw = QtWidgets.QTreeWidget()
        self.tw.setHeaderLabels(["Name", "Cost ($)"])
        cg = QtWidgets.QTreeWidgetItem(["carrots", "0.99"])
        c1 = QtWidgets.QTreeWidgetItem(["carrot", "0.33"])
        self.tw.addTopLevelItem(cg)
        self.tw.addTopLevelItem(c1)

        self.tw.viewport().installEventFilter(self)

        layout = QtWidgets.QVBoxLayout(self)
        layout.addWidget(self.tw)

        self.rightClicked.connect(self.handle_rightClicked)

    def eventFilter(self, source: QtWidgets.QTreeWidget, event):
        if event.type() == QtCore.QEvent.ContextMenu and source is self.tw.viewport():
            self.rightClicked.emit(event.pos())
            return True

        return super(Dialog, self).eventFilter(source, event)

    def handle_rightClicked(self, pos):
        item = self.tw.itemAt(pos)
        if item is None:
            return
        menu = QtWidgets.QMenu()
        print_action = QtWidgets.QAction("Print")
        print_action.triggered.connect(lambda checked, item=item: self.print_item(item))
        menu.addAction(print_action)
        menu.exec_(self.tw.viewport().mapToGlobal(pos))

    def print_item(self, item):
        if item is None:
            return
        texts = []
        for i in range(item.columnCount()):
            text = item.text(i)
            texts.append(text)

        print("B: {}".format(",".join(texts)))

雖然沒有必要使用 eventFilter 來處理 contextmenu，因為更簡單的解決方案是將 QTreeWidget 的 contextMenuPolicy 設置為 Qt::CustomContextMenu 并使用 customContextMenuRequested 信號:

Although it is unnecessary that you use an eventFilter to handle the contextmenu since a simpler solution is to set the contextMenuPolicy of the QTreeWidget to Qt::CustomContextMenu and use the customContextMenuRequested signal:

class Dialog(QtWidgets.QDialog):
    def __init__(self, parent=None):
        super(Dialog, self).__init__()

        self.tw = QtWidgets.QTreeWidget()
        self.tw.setHeaderLabels(["Name", "Cost ($)"])
        cg = QtWidgets.QTreeWidgetItem(["carrots", "0.99"])
        c1 = QtWidgets.QTreeWidgetItem(["carrot", "0.33"])
        self.tw.addTopLevelItem(cg)
        self.tw.addTopLevelItem(c1)

        self.tw.setContextMenuPolicy(QtCore.Qt.CustomContextMenu)
        self.tw.customContextMenuRequested.connect(self.handle_rightClicked)

        layout = QtWidgets.QVBoxLayout(self)
        layout.addWidget(self.tw)

    def handle_rightClicked(self, pos):
        item = self.tw.itemAt(pos)
        if item is None:
            return
        menu = QtWidgets.QMenu()
        print_action = QtWidgets.QAction("Print")
        print_action.triggered.connect(lambda checked, item=item: self.print_item(item))
        menu.addAction(print_action)
        menu.exec_(self.tw.viewport().mapToGlobal(pos))

    def print_item(self, item):
        if item is None:
            return
        texts = []
        for i in range(item.columnCount()):
            text = item.text(i)
            texts.append(text)

        print("B: {}".format(",".join(texts)))

這篇關于帶有上下文菜單的 QTreeWidget，無法獲取正確的項目的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！