如何使用按钮浏览下一个和上一个列表项？

Question

我有一个清单：

files = ["image1.png", "image2.png", "image3.png", "image4.png", "image5.png", "image6.png"]

还有 PyQt5 按钮和一个标签：

我怎样才能将列表的第一项放在标签上，然后逐个浏览列表：

下一步按钮（单击、image2.png、单击、image3.png、单击、image4. png...)

上一个按钮（单击、image3.png、单击、image2.png、单击、image1. png...)

并且标签应该相应地更新。

我已经尝试了一整天并寻找答案，但无法让它发挥作用。 This 可能会有所帮助，不过我的技能不足以利用这些建议。

创建上述按钮窗口的所有代码：

import sys
from PyQt5.QtWidgets import QApplication, QWidget, QPushButton, QLabel
from PyQt5.QtGui import QIcon
from PyQt5.QtCore import pyqtSlot

class App(QWidget):

    def __init__(self):
        super().__init__()
        self._files = deque()
        self._filesCount = len(self._files)
        self._setupUI()
        self._connectSignalsSlots()

    def __init__(self):
        super().__init__()
        self.title = 'PyQt5 button - pythonspot.com'
        self.left = 10
        self.top = 10
        self.width = 320
        self.height = 200
        self.initUI()

    def initUI(self):
        self.setWindowTitle(self.title)
        self.setGeometry(self.left, self.top, self.width, self.height)

        button = QPushButton('Print Files List', self)
        button.move(100,70)
        button.clicked.connect(self.loadFiles)

        self.setWindowTitle(self.title)
        self.setGeometry(self.left, self.top, self.width, self.height)

        button = QPushButton('Print Next Filename', self)
        button.move(160,110)
        button.clicked.connect(self.nextFilename)
        label = QLabel('image1.png (should be first of the list, \n and update with button presses)', self)
        label.move(35,140)

        button = QPushButton('Print Previous Filename', self)
        button.move(10,110)
        button.clicked.connect(self.previousFilename)

        self.show()

    @pyqtSlot()
    def loadFiles(self):
        files = ["image1.png", "image2.png", "image3.png", "image4.png", "image5.png", "image6.png"]
        if len(files) > 0:
            for file in files:
                print(file)

    def nextFilename(self):
        print('nextFilenameButton click')

    def previousFilename(self):
        print('previousFilenameButton click')

if __name__ == '__main__':
    app = QApplication(sys.argv)
    ex = App()
    sys.exit(app.exec_())

Answer 1

解决方案是处理用于获取文件名的索引（或光标）。并且该索引必须通过按钮修改

import sys

from PyQt5.QtGui import QPixmap
from PyQt5.QtWidgets import QApplication, QGridLayout, QLabel, QPushButton, QWidget


class Widget(QWidget):
    def __init__(self, parent=None):
        super().__init__(parent)
        self._current_index = 0
        self._filenames = []

        self.previous_button = QPushButton("Previous")
        self.next_button = QPushButton("Next")
        self.print_button = QPushButton("Print")
        self.label = QLabel()

        lay = QGridLayout(self)
        lay.addWidget(self.previous_button, 0, 0)
        lay.addWidget(self.next_button, 0, 1)
        lay.addWidget(self.print_button, 0, 2)
        lay.addWidget(self.label, 1, 0, 1, 3)

        self.previous_button.clicked.connect(self.handle_previous)
        self.next_button.clicked.connect(self.handle_next)
        self.print_button.clicked.connect(self.handle_print)

        self._update_button_status(False, True)

        self.load_files()

    def load_files(self):
        self._filenames = [
            "image1.png",
            "image2.png",
            "image3.png",
            "image4.png",
            "image5.png",
            "image6.png",
        ]
        self.current_index = 0

    def handle_next(self):
        self.current_index += 1

    def handle_previous(self):
        self.current_index -= 1

    def handle_print(self):
        for filename in self._filenames:
            print(filename)

    @property
    def current_index(self):
        return self._current_index

    @current_index.setter
    def current_index(self, index):
        if index <= 0:
            self._update_button_status(False, True)
        elif index >= (len(self._filenames) - 1):
            self._update_button_status(True, False)
        else:
            self._update_button_status(True, True)

        if 0 <= index < len(self._filenames):
            self._current_index = index
            filename = self._filenames[self._current_index]
            pixmap = QPixmap(filename)
            self.label.setPixmap(pixmap)

    def _update_button_status(self, previous_enable, next_enable):
        self.previous_button.setEnabled(previous_enable)
        self.next_button.setEnabled(next_enable)


if __name__ == "__main__":
    app = QApplication(sys.argv)
    w = Widget()
    w.resize(640, 480)
    w.show()
    sys.exit(app.exec_())

注意：拥有 2 个同名方法是没有用的，因为在 python 中只会使用最后一个实现。