【QTdesigner】课时40.下拉列表控件（QComboBox）【pyqt5+QTdesigner模式】

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视频链接

P39课时40.下拉列表控件（QComboBox）

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课程重点

下拉列表

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代码位置

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完整代码

'''

下拉列表控件（QComboBox）

1. 如果将列表项添加到QComboBox控件中

2. 如何获取选中的列表项

'''

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

class QComboBoxDemo(QWidget):
    def __init__(self):
        super(QComboBoxDemo,self).__init__()
        self.initUI()

    def initUI(self):
        self.setWindowTitle('下拉列表控件演示')
        self.resize(300,100)

        layout = QVBoxLayout()

        self.label = QLabel('请选择编程语言')

        self.cb = QComboBox()
        self.cb.addItem('C++')
        self.cb.addItem('Python')
        self.cb.addItems(['Java','C#','Ruby'])

        self.cb.currentIndexChanged.connect(self.selectionChange)

        layout.addWidget(self.label)
        layout.addWidget(self.cb)

        self.setLayout(layout)

    def selectionChange(self,i):
        self.label.setText(self.cb.currentText())
        self.label.adjustSize()

        for count in range(self.cb.count()):
            print('item' + str(count) + '=' + self.cb.itemText(count))

        print('current index',i,'selection changed', self.cb.currentText())

if __name__ == '__main__':
    app = QApplication(sys.argv)
    main = QComboBoxDemo()
    main.show()
    sys.exit(app.exec_())

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遇到的问题

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改写效果展示

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改写注意点

双击窗口，弹出添加框

测试功能：sizeAdjustPolicy

说明这个设置优先级高一些！

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改写代码（QTdesigner模式）

# -*- coding:utf-8 -*-
'''
@Author: knocky
@Blog: https://blog.csdn.net/zzx188891020
@E-mail: [email protected]
@File: class_X.py
@CreateTime: 2020/5/11 23:36
'''

import sys
from PyQt5.QtWidgets import QApplication
from PyQt5 import uic


class my_form():
    def __init__(self):
        super().__init__()
        self.ui = uic.loadUi("../ui_package/class40.ui")
        self.ui.comboBox.currentIndexChanged.connect(self.selectionChange)

    def selectionChange(self, i): # 这里的i应该是接受信号，说明currentIndexChanged有返回值
        self.ui.label.setText(self.ui.comboBox.currentText())
        self.ui.label.adjustSize()

        for count in range(self.ui.comboBox.count()):
            print('item' + str(count) + '=' + self.ui.comboBox.itemText(count))

        print('current index', i, 'selection changed', self.ui.comboBox.currentText())


if __name__ == '__main__':
    app = QApplication(sys.argv)
    main = my_form()
    main.ui.show()
    sys.exit(app.exec_())