from PyQt5.QtWidgets import QMainWindow, QLabel
from PyQt5.QtCore import Qt

class ProfessionalApp(QMainWindow):
    def __init__(self):
        super().__init__()
        self.setWindowTitle("專業(yè)級應用示例")
        self.resize(1000, 700)

        # ? 唯一必須設置的部分：中央部件
        central = QLabel("這里是你的主界面", alignment=Qt.AlignCenter)
        self.setCentralWidget(central)

        # ?? 下面這些，隨你開不開，全由你控制
        self._setup_menu_bar()
        self._setup_tool_bars()
        self._setup_status_bar()
        self._setup_dock_widgets()

from PyQt5.QtWidgets import QStackedWidget, QWidget, QVBoxLayout, QPushButton

class PageController(QStackedWidget):
    def __init__(self):
        super().__init__()
        self._pages = {}  # 緩存頁面實例
        self.init_pages()

    def init_pages(self):
        # 頁面0 - 主頁
        home = QWidget()
        layout = QVBoxLayout()
        layout.addWidget(QPushButton("去設置"))
        home.setLayout(layout)
        self.addWidget(home)
        self._pages['home'] = home

        # 頁面1 - 設置頁
        settings = QWidget()
        layout = QVBoxLayout()
        layout.addWidget(QPushButton("回主頁"))
        settings.setLayout(layout)
        self.addWidget(settings)
        self._pages['settings'] = settings

        # 默認顯示首頁
        self.setCurrentIndex(0)

# 監(jiān)聽頁面切換
self.currentChanged.connect(self.on_page_changed)

def on_page_changed(self, index):
    print(f"?? 用戶進入了第 {index} 個頁面")
    page_map = {0: "主頁", 1: "設置頁"}
    self.parent().statusBar().showMessage(f"進入: {page_map.get(index, '未知')}")

    # 更進一步：根據(jù)頁面類型執(zhí)行不同邏輯
    current_widget = self.widget(index)
    if hasattr(current_widget, 'on_enter'):
        current_widget.on_enter()  # 觸發(fā)頁面專屬的“進入”行為

class LazyStackedWidget(QStackedWidget):
    def __init__(self):
        super().__init__()
        self._factories = {}  # 存儲“造頁面”的函數(shù)
        self._loaded = set()  # 記錄已加載的頁面索引

    def add_lazy_page(self, index: int, create_func, placeholder_text="加載中..."):
        """注冊一個延遲加載的頁面"""
        placeholder = QLabel(placeholder_text, alignment=Qt.AlignCenter)
        self.insertWidget(index, placeholder)
        self._factories[index] = create_func

        # 當該頁面首次被激活時，才真正創(chuàng)建
        def load_once():
            if index not in self._loaded:
                real_page = create_func()
                self.removeWidget(placeholder)
                self.insertWidget(index, real_page)
                self._loaded.add(index)
                placeholder.deleteLater()

        # 使用一次性的連接，避免重復觸發(fā)
        from functools import partial
        self.widgetRemoved.connect(partial(lambda i, f=load_once: f() if i == index else None))

    def setCurrentIndex(self, index):
        # 強制刷新：先移除再設回，觸發(fā) widgetRemoved 信號
        if index in self._factories and index not in self._loaded:
            old_idx = self.currentIndex()
            self.parent().setCentralWidget(QWidget())  # 臨時替換
            self.parent().setCentralWidget(self)       # 再換回來
            super().setCurrentIndex(old_idx)
            super().setCurrentIndex(index)
        else:
            super().setCurrentIndex(index)

def create_heavy_page():
    # 模擬耗時操作
    import time; time.sleep(1)
    page = QWidget()
    page.setLayout(QVBoxLayout())
    page.layout().addWidget(QLabel("這是個重型頁面，加載花了1秒"))
    return page

stack = LazyStackedWidget()
stack.add_lazy_page(0, lambda: QLabel("輕量首頁"), "首頁")
stack.add_lazy_page(1, create_heavy_page, "重型頁面...")

btn.clicked.connect(lambda: stack.setCurrentIndex(1))  # ? 硬編碼！

settings_page = SettingsWidget()
stack.addWidget(settings_page)

btn.clicked.connect(lambda: stack.setCurrentWidget(settings_page))  # ? 推薦！

from PyQt5.QtCore import pyqtSignal

class NavigationRequest(QObject):
    goto_login = pyqtSignal()
    goto_main = pyqtSignal()
    goto_settings = pyqtSignal()
    goto_help = pyqtSignal()

# 全局信號總線（或作為主窗口成員）
nav = NavigationRequest()

class LoginPage(QWidget):
    def __init__(self):
        super().__init__()
        btn = QPushButton("登錄")
        btn.clicked.connect(self.try_login)

    def try_login(self):
        # 模擬驗證
        if self.validate():
            nav.goto_main.emit()  # 發(fā)信號：我要去主頁面！

class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        self.stack = QStackedWidget()
        self.setCentralWidget(self.stack)

        # 創(chuàng)建頁面
        self.login_page = LoginPage()
        self.main_page = MainPage()
        self.settings_page = SettingsPage()

        self.stack.addWidget(self.login_page)
        self.stack.addWidget(self.main_page)
        self.stack.addWidget(self.settings_page)

        # 統(tǒng)一處理導航信號
        nav.goto_main.connect(lambda: self.stack.setCurrentWidget(self.main_page))
        nav.goto_settings.connect(lambda: self.stack.setCurrentWidget(self.settings_page))
        nav.goto_help.connect(lambda: self.stack.setCurrentWidget(self.help_page))

class MainPage(QWidget):
    def __init__(self, user: User):
        super().__init__()
        self.user = user
        layout = QVBoxLayout()
        layout.addWidget(QLabel(f"歡迎回來，{user.username}！"))
        self.setLayout(layout)

# 登錄成功后
user = User(username="alice", role="admin")
main_page = MainPage(user)
stack.addWidget(main_page)
nav.goto_main.emit()

main_page.user = user  # 在 emit 前設置
nav.goto_main.emit()

class AppState(QObject):
    user_changed = pyqtSignal(User)

    def __init__(self):
        super().__init__()
        self._current_user = None

    @property
    def current_user(self):
        return self._current_user

    @current_user.setter
    def current_user(self, value):
        self._current_user = value
        self.user_changed.emit(value)

# 全局狀態(tài)
app_state = AppState()

# 任何頁面監(jiān)聽用戶變化
app_state.user_changed.connect(lambda u: print(f"用戶變更為: {u.username}"))

pyuic5 -x ui/login.ui -o views/ui_login.py

class Ui_LoginForm(object):
    def setupUi(self, LoginForm):
        LoginForm.setObjectName("LoginForm")
        LoginForm.resize(400, 300)
        self.lineEdit_username = QLineEdit(LoginForm)
        self.lineEdit_username.setGeometry(...)
        self.lineEdit_password = QLineEdit(LoginForm)
        self.lineEdit_password.setEchoMode(QLineEdit.Password)
        self.btn_login = QPushButton("登錄", LoginForm)

    def retranslateUi(self, LoginForm):
        _translate = QCoreApplication.translate
        LoginForm.setWindowTitle(_translate("LoginForm", "登錄"))

from views.ui_login import Ui_LoginForm

class LoginWindow(QWidget, Ui_LoginForm):
    def __init__(self):
        super().__init__()
        self.setupUi(self)  # 自動生成界面
        self.btn_login.clicked.connect(self.handle_login)

    def handle_login(self):
        username = self.lineEdit_username.text()
        password = self.lineEdit_password.text()
        if authenticate(username, password):
            app_state.current_user = User(username, "user")
            nav.goto_main.emit()
        else:
            QMessageBox.warning(self, "錯誤", "用戶名或密碼錯誤")

# tools/compile_ui.py
import os
import subprocess

UI_DIR = "ui"
VIEWS_DIR = "views"

def compile_all():
    for file in os.listdir(UI_DIR):
        if file.endswith(".ui"):
            input_path = os.path.join(UI_DIR, file)
            output_name = f"ui_{file[:-3]}.py"
            output_path = os.path.join(VIEWS_DIR, output_name)
            cmd = ["pyuic5", "-o", output_path, input_path]
            subprocess.run(cmd, check=True)
            print(f"? 生成: {output_path}")

if __name__ == "__main__":
    compile_all()

pip install pyinstaller