Python GUI框架中的PyQt详解

from PyQt5.QtCore import QTimer, QObject, pyqtSignal
class Worker(QObject):
    update_signal = pyqtSignal(str)
    def __init__(self):
        super().__init__()
        self.timer = QTimer()
        self.timer.timeout.connect(self.update_time)
    def update_time(self):
        from datetime import datetime
        self.update_signal.emit(datetime.now().strftime("%H:%M:%S"))
    def start(self):
        self.timer.start(1000)  # 每秒触发

 
from PyQt5.QtWidgets import QApplication, QMainWindow, QPushButton
class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        self.setWindowTitle("PyQt Demo")
        self.setGeometry(100, 100, 400, 300)
        btn = QPushButton("点击我", self)
        btn.move(150, 150)
        btn.clicked.connect(self.on_click)
    def on_click(self):
        print("按钮被点击！")
if __name__ == "__main__":
    app = QApplication([])
    window = MainWindow()
    window.show()
    app.exec_()

from PyQt5.QtWidgets import QWidget
from PyQt5.QtGui import QPainter, QColor
class Canvas(QWidget):
    def paintEvent(self, event):
        painter = QPainter(self)
        painter.setBrush(QColor(255, 0, 0))
        painter.drawEllipse(50, 50, 100, 100)  # 绘制红色圆形

from PyQt5.QtNetwork import QNetworkAccessManager, QNetworkRequest
from PyQt5.QtCore import QUrl
class Downloader:
    def __init__(self):
        self.manager = QNetworkAccessManager()
        self.manager.finished.connect(self.handle_response)
    def fetch(self, url):
        request = QNetworkRequest(QUrl(url))
        self.manager.get(request)
    def handle_response(self, reply):
        data = reply.readAll()
        print(f"收到 {len(data)} 字节数据")

 
from PyQt5.QtSql import QSqlDatabase, QSqlQuery
# 创建数据库连接
db = QSqlDatabase.addDatabase("QSQLITE")
db.setDatabaseName("mydatabase.db")
if db.open():
    query = QSqlQuery()
    query.exec_("CREATE TABLE IF NOT EXISTS users (id INTEGER PRIMARY KEY, name TEXT)")
    query.exec_("INSERT INTO users (name) VALUES ('Alice')")
    db.close()

 
from PyQt5.QtWebEngineWidgets import QWebEngineView
from PyQt5.QtWidgets import QMainWindow
class BrowserWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        self.browser = QWebEngineView()
        self.setCentralWidget(self.browser)
        self.browser.load(QUrl("https://www.example.com"))

# 包含网络请求、UI控件、JSON解析的完整示例
import sys
import json
from PyQt5.QtWidgets import (QApplication, QWidget, QVBoxLayout, 
                             QLineEdit, QLabel, QPushButton)
from PyQt5.QtNetwork import QNetworkAccessManager
class WeatherApp(QWidget):
    def __init__(self):
        super().__init__()
        self.manager = QNetworkAccessManager()
        self.manager.finished.connect(self.handle_response)
        self.init_ui()
    def init_ui(self):
        layout = QVBoxLayout()
        self.city_input = QLineEdit("输入城市")
        self.result_label = QLabel("等待查询...")
        btn = QPushButton("查询天气")
        btn.clicked.connect(self.query_weather)
        layout.addWidget(self.city_input)
        layout.addWidget(btn)
        layout.addWidget(self.result_label)
        self.setLayout(layout)
    def query_weather(self):
        city = self.city_input.text()
        url = f"http://weather-api.com/{city}"
        self.manager.get(QNetworkRequest(QUrl(url)))
    def handle_response(self, reply):
        data = json.loads(reply.readAll().data())
        temp = data['main']['temp']
        self.result_label.setText(f"当前温度：{temp}°C")
if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = WeatherApp()
    window.show()
    sys.exit(app.exec_())

pip install pyqt5  # 基本安装
pip install pyqt5-tools  # 包含Qt Designer等工具