PyQt не может добавить tableWIdget в существующее приложение

Решено, проблема была здесь:

self.add_controls()
self.createTable()

так как я звонил add_controls() перед созданием таблицы, в результате чего:

'App' object has no attribute 'tableWidget'

Попытайся:

import sys
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
from PyQt5.QtCore import *
from PyQt5.QtMultimedia import QMediaPlayer, QMediaPlaylist

class App(QMainWindow):

    def __init__(self):
        super().__init__()
        self.player   = QMediaPlayer()     # QMediaPlayer class allows the playing of a media source.
        self.playlist = QMediaPlaylist()   # QMediaPlaylist class provides a list of media content to play.
        self.title    = 'PyTunes'
        self.left   = 300
        self.top    = 300
        self.width  = 300
        self.height = 150
        self.color  = 0       # 0- toggle to dark 1- toggle to light
        self.userAction = -1  # 0- stopped, 1- playing 2-paused

        self.setup_UI()

    def setup_UI(self):
        # Add file menu
        menubar    = self.menuBar()
        filemenu   = menubar.addMenu('File')
        windowmenu = menubar.addMenu('Window')

        help_act   = QAction('Open Help', self)
        folder_act = QAction('Open Folder', self)
        theme_act  = QAction('Toggle light/dark theme', self)

        folder_act.setShortcut('Ctrl+D')
        help_act.setShortcut(  'Ctrl+H')
        theme_act.setShortcut( 'Ctrl+T')

        filemenu.addAction(folder_act)
        filemenu.addAction(help_act)
        windowmenu.addAction(theme_act)

#        help_act.triggered.connect(  self.open_help)
#        folder_act.triggered.connect(self.add_files)
#        theme_act.triggered.connect( self.toggle_colors)

        self.add_controls()

        self.createTable()

        self.control_area.addWidget(self.tableWidget)                  # <===============

        self.setWindowTitle(self.title)
        self.setGeometry(self.left, self.top, self.width, self.height)
#?        self.toggle_colors()
        self.show()

    def add_controls(self):
        wid = QWidget(self)
        self.setCentralWidget(wid)

        # Add song controls
        volumeslider = QSlider(Qt.Horizontal, self)
        volumeslider.setFocusPolicy(Qt.NoFocus)
#        volumeslider.valueChanged[int].connect(self.change_volume)
        volumeslider.setValue(100)

        play_btn  = QPushButton('Play')  # play button
        pause_btn = QPushButton('Pause')  # pause button
        stop_btn  = QPushButton('Stop')  # stop button

        # Add playlist controls
        prev_btn    = QPushButton('Prev')
        shuffle_btn = QPushButton('Shuffle')
        next_btn    = QPushButton('Next')
        sort_btn    = QPushButton('Sort')
        search_btn  = QPushButton('Search')
        remove_btn  = QPushButton('Remove')

        # Add button layouts
        self.control_area = QVBoxLayout()                    # + self.            
        controls     = QHBoxLayout()
        playlist_ctrl_layout = QHBoxLayout()
        playlist_func = QHBoxLayout()

        # Add buttons to song controls layout
        controls.addWidget(play_btn)
        controls.addWidget(pause_btn)
        controls.addWidget(stop_btn)

        # Add buttons to playlist controls layout
        playlist_ctrl_layout.addWidget(prev_btn)
        playlist_ctrl_layout.addWidget(shuffle_btn)
        playlist_ctrl_layout.addWidget(next_btn)

        playlist_func.addWidget(sort_btn)
        playlist_func.addWidget(search_btn)
        playlist_func.addWidget(remove_btn)

        # Add to vertical layout
        self.control_area.addLayout(controls)                # + self. 
        self.control_area.addLayout(playlist_ctrl_layout)    # + self. 
        self.control_area.addWidget(volumeslider)            # + self. 
        self.control_area.addLayout(playlist_func)           # + self. 

        # control_area.addWidget(QTableWidget)   
        # control_area.addWidget(self.tableWidget)

        wid.setLayout(self.control_area)                     # + self. 

        # Connect each signal to their appropriate function
#        play_btn.clicked.connect(self.play_handler)
#        pause_btn.clicked.connect(self.pause_handler)
#        stop_btn.clicked.connect(self.stop_handler)

#        prev_btn.clicked.connect(self.prev_song)
#        shuffle_btn.clicked.connect(self.shuffle_list)
#        next_btn.clicked.connect(self.next_song)

#        sort_btn.clicked.connect(self.sort_handler)
#        search_btn.clicked.connect(self.search_handler)
#        remove_btn.clicked.connect(self.remove_handler)

        self.statusBar()
        # Signal emitted when current media changes. Call song_changed
#        self.playlist.currentMediaChanged.connect(self.song_changed)

    def createTable(self):
        # Create table
        self.tableWidget = QTableWidget()
        self.tableWidget.setRowCount(4)
        self.tableWidget.setColumnCount(2)
        self.tableWidget.setItem(0, 0, QTableWidgetItem("Cell (1,1)"))
        self.tableWidget.setItem(0, 1, QTableWidgetItem("Cell (1,2)"))
        self.tableWidget.setItem(1, 0, QTableWidgetItem("Cell (2,1)"))
        self.tableWidget.setItem(1, 1, QTableWidgetItem("Cell (2,2)"))
        self.tableWidget.setItem(2, 0, QTableWidgetItem("Cell (3,1)"))
        self.tableWidget.setItem(2, 1, QTableWidgetItem("Cell (3,2)"))
        self.tableWidget.setItem(3, 0, QTableWidgetItem("Cell (4,1)"))
        self.tableWidget.setItem(3, 1, QTableWidgetItem("Cell (4,2)"))
        self.tableWidget.move(0, 0)

        # table selection change
        self.tableWidget.doubleClicked.connect(self.on_click)

    @pyqtSlot()
    def on_click(self):
        print("\n")
        for currentQTableWidgetItem in self.tableWidget.selectedItems():
            print(currentQTableWidgetItem.row(), 
                  currentQTableWidgetItem.column(), 
                  currentQTableWidgetItem.text())

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