qt.qpa.xcb：无法连接显示 qt.qpa.plugin：无法加载 Qt 平台插件“xcb”

Question

运行下面的代码后，我收到以下错误：

Got keys from plugin meta data ("xcb")
QFactoryLoader::QFactoryLoader() checking directory path "/usr/bin/platforms" ...
loaded library "/usr/lib/arm-linux-gnueabihf/qt5/plugins/platforms/libqxcb.so"
qt.qpa.xcb: could not connect to display
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Available platform plugins are: eglfs, linuxfb, minimal, minimalegl, offscreen, vnc, xcb.

Aborted

任何想法如何解决这一问题？

import sys
import time
 
import requests
from PyQt5.QtCore import QObject, QRunnable, QThreadPool, QTimer, pyqtSignal, pyqtSlot
from PyQt5.QtWidgets import (
    QApplication, QLabel, QMainWindow,  QPlainTextEdit, QPushButton, QVBoxLayout, QWidget,
    )
 
from bluepy import btle
 
class WorkerSignals(QObject):
    signalMsg = pyqtSignal(str)
    signalRes = pyqtSignal(str)
    
class MyDelegate(btle.DefaultDelegate):
    
    def __init__(self, sgn):
        btle.DefaultDelegate.__init__(self)
        self.sgn = sgn
 
    def handleNotification(self, cHandle, data):
        
        try:
            dataDecoded = data.decode()
            self.sgn.signalRes.emit(dataDecoded)
        except UnicodeError:
            print("UnicodeError: ", data)
 
class WorkerBLE(QRunnable):
    
    def __init__(self):
        super().__init__()
        self.signals = WorkerSignals()
        self.rqsToSend = False
        
    @pyqtSlot()
    def run(self):
        self.signals.signalMsg.emit("WorkerBLE start")
        
        #---------------------------------------------
        p = btle.Peripheral("3c:71:bf:0d:dd:6a")
        p.setDelegate( MyDelegate(self.signals) )
 
        svc = p.getServiceByUUID("6E400001-B5A3-F393-E0A9-E50E24DCCA9E")
        self.ch_Tx = svc.getCharacteristics("6E400002-B5A3-F393-E0A9-E50E24DCCA9E")[0]
        ch_Rx = svc.getCharacteristics("6E400003-B5A3-F393-E0A9-E50E24DCCA9E")[0]
 
        setup_data = b"\x01\00"
        p.writeCharacteristic(ch_Rx.valHandle+1, setup_data)
 
        # BLE loop --------
 
        while True:
            """
            if p.waitForNotifications(1.0):
                # handleNotification() was called
                continue
 
            print("Waiting...")
            """
            
            p.waitForNotifications(1.0)
            
            if self.rqsToSend:
                self.rqsToSend = False
 
                try:
                    self.ch_Tx.write(self.bytestosend, True)
                except btle.BTLEException:
                    print("btle.BTLEException");
            
        #---------------------------------------------hellohello
        self.signals.signalMsg.emit("WorkerBLE end")
        
    def toSendBLE(self, tosend):
        self.bytestosend = bytes(tosend, 'utf-8')
        self.rqsToSend = True
        """
        try:
            self.ch_Tx.write(bytestosend, True)
        except BTLEException:
            print("BTLEException");
        """
            
class MainWindow(QMainWindow):
    
    def __init__(self):
        super().__init__()
        
        layout = QVBoxLayout()
        
        buttonStartBLE = QPushButton("Start BLE")
        buttonStartBLE.pressed.connect(self.startBLE)
        
        self.console = QPlainTextEdit()
        self.console.setReadOnly(True)
        
        self.outconsole = QPlainTextEdit()
        
        buttonSendBLE = QPushButton("Send message")
        buttonSendBLE.pressed.connect(self.sendBLE)
 
        layout.addWidget(buttonStartBLE)
        layout.addWidget(self.console)
        layout.addWidget(self.outconsole)
        layout.addWidget(buttonSendBLE)
        
        w = QWidget()
        w.setLayout(layout)
        
        self.setCentralWidget(w)
        
        self.show()
        self.threadpool = QThreadPool()
        print(
            "Multithreading with Maximum %d threads" % self.threadpool.maxThreadCount())
            
    def startBLE(self):
        self.workerBLE = WorkerBLE()
        self.workerBLE.signals.signalMsg.connect(self.slotMsg)
        self.workerBLE.signals.signalRes.connect(self.slotRes)
        self.threadpool.start(self.workerBLE)
        
    def sendBLE(self):
        strToSend = self.outconsole.toPlainText()
        self.workerBLE.toSendBLE(strToSend)
        
    def slotMsg(self, msg):
        print(msg)
        
    def slotRes(self, res):
        self.console.appendPlainText(res)
        
app = QApplication(sys.argv)
window = MainWindow()
app.exec()

Answer 1

如果您从会话运行此应用程序，ssh请确保display通过运行设置环境变量export DISPLAY=:0.0 # Or any other port并连接显示器