PySide6 GUI 编程（9）：QComboBox的使用

from datetime import datetime

from PySide6.QtWidgets import QApplication, QComboBox, QLabel, QMainWindow, QVBoxLayout, QWidget


class MyCombobox(QMainWindow):
    def __init__(self):
        super().__init__()

        self.my_label_item = QLabel()
        self.my_label_index = QLabel()
        self.current_time = QLabel()

        self.my_combobox = QComboBox()
        self.my_combobox.addItems(['aes-cbc', 'aes-gcm', 'aes-ofb', 'rsa-2048', 'rsa-4096', 'ecc'])
        self.my_combobox.currentTextChanged.connect(self.text_changed)
        self.my_combobox.currentIndexChanged.connect(self.index_changed)

        self.my_label_item.setText(
            'now, current item: {}'.format(
                self.my_combobox.currentText()))

        self.my_label_index.setText(
            'now, current index: {}'.format(
                self.my_combobox.currentIndex()))

        self.current_time.setText(
            datetime.now().strftime('%Y-%m-%d %H:%M:%S %z')
        )

        layout = QVBoxLayout()
        layout.addWidget(self.my_label_item)
        layout.addWidget(self.my_label_index)
        layout.addWidget(self.current_time)
        layout.addWidget(self.my_combobox)

        container = QWidget()
        container.setLayout(layout)

        self.setCentralWidget(container)

    def text_changed(self, data: str):
        self.my_label_item.setText('chose item: {}'.format(data))

    def index_changed(self, index: int):
        self.my_label_index.setText('chose index: {}'.format(index))
        self.current_time.setText(
            datetime.now().strftime('%Y-%m-%d %H:%M:%S %z')
        )


if __name__ == '__main__':
    app = QApplication()
    ins = MyCombobox()
    ins.show()
    app.exec()

from datetime import datetime

from PySide6.QtWidgets import QApplication, QComboBox, QLabel, QMainWindow, QVBoxLayout, QWidget


class MyCombobox(QMainWindow):
    def __init__(self):
        super().__init__()

        self.my_label_item = QLabel()
        self.my_label_index = QLabel()
        self.current_time = QLabel()

        self.my_combobox = QComboBox()
        self.my_combobox.addItems(['aes-cbc', 'aes-gcm', 'aes-ofb', 'rsa-2048', 'rsa-4096', 'ecc'])
        self.my_combobox.currentTextChanged.connect(self.text_changed)
        self.my_combobox.currentIndexChanged.connect(self.index_changed)
        self.my_combobox.editTextChanged.connect(self.edit_text_changed)

        self.my_combobox.setMaxCount(100)  # 可以存储的最大项数
        self.my_combobox.setMaxVisibleItems(10)  # 每次下拉时最大的展示项数

        # 当设置为True时，用户可以在下拉列表的文本框中输入文本
        # 而不仅仅是从列表中选择现有的项
        # 这允许用户输入一个可能不在当前列表中的值
        self.my_combobox.setEditable(True)

        # 无论 QComboBox 是否可编辑，都可以使用此方法设置当前显示在编辑框中的文本
        # 使用 setEditText 可以快速设置 QComboBox 显示的文本，而不需要用户从列表中选择
        self.my_combobox.setEditText('edit text here')

        self.my_label_item.setText(
            'now, current item: {}'.format(
                self.my_combobox.currentText()))

        self.my_label_index.setText(
            'now, current index: {}'.format(
                self.my_combobox.currentIndex()))

        self.current_time.setText(
            datetime.now().strftime('%Y-%m-%d %H:%M:%S %z')
        )

        layout = QVBoxLayout()
        layout.addWidget(self.my_label_item)
        layout.addWidget(self.my_label_index)
        layout.addWidget(self.current_time)
        layout.addWidget(self.my_combobox)

        container = QWidget()
        container.setLayout(layout)

        self.setCentralWidget(container)

    def text_changed(self, data: str):
        self.my_label_item.setText('chose item: {}'.format(data))

    def index_changed(self, index: int):
        self.my_label_index.setText('chose index: {}'.format(index))
        self.current_time.setText(
            datetime.now().strftime('%Y-%m-%d %H:%M:%S %z')
        )

    def edit_text_changed(self, data: str):
        self.my_label_item.setText('edit text changed to: {}'.format(data))


if __name__ == '__main__':
    app = QApplication()
    ins = MyCombobox()
    ins.show()
    app.exec()

from PySide6.QtWidgets import QApplication, QComboBox, QVBoxLayout, QWidget


def main():
    app = QApplication([])

    # 创建一个QWidget作为主窗口
    window = QWidget()
    layout = QVBoxLayout(window)

    # 创建一个QComboBox实例
    comboBox = QComboBox()
    comboBox.setEditable(True)  # 使下拉列表可编辑

    # 添加一些选项
    comboBox.addItems(["选项1", "选项2", "选项3"])

    # 设置占位符文本
    # 在 macOS 系统上，QComboBox 的 setPlaceholderText 方法可能不会按预期工作
    # 因为 macOS 的用户界面指南通常不支持在组合框中使用占位符文本
    # Qt 的某些版本可能没有完全支持在 macOS 上为 QComboBox 显示占位符文本
    comboBox.setPlaceholderText("请选择或输入一个选项")

    # 将QComboBox添加到布局中
    layout.addWidget(comboBox)

    # 显示窗口
    window.show()

    # 启动应用程序
    app.exec()


if __name__ == "__main__":
    main()

    class InsertPolicy(enum.Enum):

        NoInsert                 : QComboBox.InsertPolicy = ... # 0x0
        InsertAtTop              : QComboBox.InsertPolicy = ... # 0x1
        InsertAtCurrent          : QComboBox.InsertPolicy = ... # 0x2
        InsertAtBottom           : QComboBox.InsertPolicy = ... # 0x3
        InsertAfterCurrent       : QComboBox.InsertPolicy = ... # 0x4
        InsertBeforeCurrent      : QComboBox.InsertPolicy = ... # 0x5
        InsertAlphabetically     : QComboBox.InsertPolicy = ... # 0x6

from PySide6.QtWidgets import QApplication, QComboBox, QMainWindow


class MyComboBox(QMainWindow):
    def __init__(self):
        super().__init__()
        self.setWindowTitle('ComboBox设置写入策略')

        my_box = QComboBox()
        my_box.addItems(['a', 'b', 'c'])
        my_box.setEditable(True)
        my_box.setMaxCount(26)
        my_box.setInsertPolicy(QComboBox.InsertPolicy.InsertAlphabetically)
        self.setCentralWidget(my_box)


if __name__ == '__main__':
    app = QApplication()
    ins = MyComboBox()
    ins.show()
    app.exec()