PyQt5 删除按钮

Question

In the list_widget I have added a add button I also want to add a remove button which asks which item you wants to remove and remove the chosen item. I was trying it to do but I didn't had any idea to do so .Also, please explain the solution I am a beginner with pyqt5 or I'd like to say absolute beginner.

from PyQt5 import QtWidgets
from PyQt5.QtWidgets import QApplication,QMainWindow, 
QListWidget, QListWidgetItem
import sys

class MyWindow(QMainWindow):
    def __init__(self):
        super(MyWindow, self).__init__()
        self.x = 200
        self.y = 200
        self.width = 500
        self.length = 500
        self.setGeometry(self.x, self.y, self.width, 
        self.length)
        self.setWindowTitle("Stock managment")

        self.iniTUI()

    def iniTUI(self):
        # buttons
        self.b1 = QtWidgets.QPushButton(self)
        self.b1.setText("+")
        self.b1.move(450, 100)
        self.b1.resize(50, 25)
        self.b1.clicked.connect(self.take_inputs)
        # This is the button I want to define.
        self.btn_minus = QtWidgets.QPushButton(self)
        self.btn_minus.setText("-")
        self.btn_minus.move(0, 100)
        self.btn_minus.resize(50, 25)


        # list
        self.list_widget = QListWidget(self)

        self.list_widget.setGeometry(120, 100, 250, 300)

        self.item1 = QListWidgetItem("A")
        self.item2 = QListWidgetItem("B")
        self.item3 = QListWidgetItem("C")

        self.list_widget.addItem(self.item1)
        self.list_widget.addItem(self.item2)
        self.list_widget.addItem(self.item3)

        self.list_widget.setCurrentItem(self.item2)



    def take_inputs(self):
        self.name, self.done1 = 
 QtWidgets.QInputDialog.getText(
            self, 'Add Item to List', 'Enter The Item you want 
in 
            the list:')
        self.roll, self.done2 = QtWidgets.QInputDialog.getInt(
            self, f'Quantity of {str(self.name)}', f'Enter 
            Quantity of {str(self.name)}:')

        if self.done1 and self.done2:
            self.item4 = QListWidgetItem(f"{str(self.name)}              
            Quantity{self.roll}")
            self.list_widget.addItem(self.item4)
            self.list_widget.setCurrentItem(self.item4)
               

    def clicked(self):
        self.label.setText("You clicked the button")
        self.update()

    def update(self):
        self.label.adjustSize()


def clicked():
    print("meow")
def window():
    apk = QApplication(sys.argv)
    win = MyWindow()





    win.show()
    sys.exit(apk.exec_())
window()

Answer 1

The core issue here is the lack of separation of the view and the data . This makes it very hard to reason about how to work with graphical elements. You will almost certainly want to follow the Model View Controller design paradigm https://en.wikipedia.org/wiki/Model%E2%80%93view%E2%80%93controller which offers a systematic way to handle this separation.

Once you do so, it immediately becomes very straight forward how to proceed with the question: You essentially just have a list, and you either want to add a thing to this list, or remove one based on a selection.

I include an example here which happens to use the built-in classes QStringListModel and QListView in Qt5, but it is simple to write your own more specialized widgets and models. They all just use a simple signal to emit to the view that it needs to refresh the active information.

from PyQt5.QtWidgets import *
from PyQt5.QtCore import *
import sys

class StuffViewer(QMainWindow):
    def __init__(self, model):
        super().__init__()
        self.setWindowTitle("Stock managment")

        # 1: Use layouts.
        hbox = QHBoxLayout()
        widget = QWidget()
        widget.setLayout(hbox)
        self.setCentralWidget(widget)

        # 2: Don't needlessly store things in "self"
        vbox = QVBoxLayout()
        add = QPushButton("+")
        add.clicked.connect(self.add_new_stuff)
        vbox.addWidget(add)
        sub = QPushButton("-")
        sub.clicked.connect(self.remove_selected_stuff)
        vbox.addWidget(sub)
        vbox.addStretch(1)
        hbox.addLayout(vbox)

        # 3: Separate the view of the data from the data itself. Use Model-View-Controller design to achieve this.
        self.model = model
        self.stuffview = QListView()
        self.stuffview.setModel(self.model)
        hbox.addWidget(self.stuffview)

    def add_new_stuff(self):
        new_stuff, success = QInputDialog.getText(self, 'Add stuff', 'Enter new stuff you want')
        if success:
            self.stuff.setStringList(self.stuff.stringList() + [new_stuff])

    def remove_selected_stuff(self):
        index = self.stuffview.currentIndex()
        all_stuff = self.stuff.stringList()
        del all_stuff[index.column()]
        self.stuff.setStringList(all_stuff)


def window():
    apk = QApplication(sys.argv)
    # Data is clearly separated:
    # 4: Never enumerate variables! Use lists!
    stuff = QStringListModel(["Foo", "Bar", "Baz"])
    # The graphical components is just how you interface with the data with the user!
    win = StuffViewer(stuff)
    win.show()
    sys.exit(apk.exec_())

window()