python - 异常断言错误: AssertionError() in 'pyobjus.protocol_forwardInvocation' ignored

Question

我正在构建一个 Kivy 应用程序，它使用 pyobjus 连接到 TI SensorTag 。我已成功让应用程序在扫描期间找到传感器，但无法连接它。我找到了一些代码here ，但它适用于不同的传感器。我收到的错误是:Exception AssertionError: AssertionError() in 'pyobjus.protocol_forwardInvocation' ignored来自 pyobjus，但我不知道如何跟踪错误，因为它被忽略了。

1. 如何找到导致错误的原因(例如防止 pyobjus 忽略错误)？
2. 更好的是，有没有人有一个简单的工作示例来说明如何通过 BLE 将设备连接到 Mac OSX？

编辑

这是代码，似乎问题出在 connect() 函数

class Ble(object):
    def check_le(self, central):
        state = central.state
        if state == CBCentralManagerStateUnknown:
            print 'CentralManager: Unknown state'
        elif state == CBCentralManagerStatePoweredOn:
            print 'CentralManager: Ready to go!'
            return True
        elif state == CBCentralManagerStatePoweredOff:
            print 'CentralManager: Bluetooth is powered off'
        elif state == CBCentralManagerStateUnauthorized:
            print 'CentralManager: The application is not authorized to use BLE'  # noqa
        elif state == CBCentralManagerStateUnsupported:
            print 'CentralManager: This hardware doesnt support BLE'

    def connect(self, peripheral):
        print "connecting"
        self.stop_scan()
        self.central.cancelPeripheralConnection_(peripheral)
        self.central.connectPeripheral_options_(peripheral, None, None)

    def disconnecte(self, peripheral):
        # XXX !
        print "Disconnect Not Implemented!"

    def create(self):
        self.callback = None
        self.peripherals = {}
        load_framework(INCLUDE.IOBluetooth)
        CBCentralManager = autoclass('CBCentralManager')
        self.central = CBCentralManager.alloc().initWithDelegate_queue_(
            self, None)

    def start_scan(self):
        print 'Scanning started on Mac OSX MJR'
        self.asked_services = []
        self.central.scanForPeripheralsWithServices_options_(None, None)
        Clock.schedule_interval(self.pop_queue, 0.04)

    def stop_scan(self):
        print "stopping scan"
        self.central.stopScan()

    def pop_queue(self, dt):
        if self.queue:
            self.callback(*self.queue.pop(0))

    @protocol('CBCentralManagerDelegate')
    def centralManagerDidUpdateState_(self, central):
        print 'central state', central.state
        self.check_le(central)
        self.start_scan()

    @protocol('CBCentralManagerDelegate')
    def centralManager_didDiscoverPeripheral_advertisementData_RSSI_(
            self, central, peripheral, data, rssi):
        # print('centralManager:didDiscoverPeripheral:advertisementData:RSSI:')
        # uuid = peripheral.identifier.UUIDString().cString()
        # if peripheral.name:
        #     print('-> name=', peripheral.name.cString())
        #     print 'uuid:', uuid

        keys = data.allKeys()
        count = keys.count()
        if count < 2:
            return
        name = peripheral.name.cString()
        # name = data.objectForKey_(keys.objectAtIndex_(count - 2)).cString()
        values = data.objectForKey_(keys.objectAtIndex_(count - 1))

        sensor = c.get_from_ptr(values.bytes().arg_ref, 'c', values.length())
        uuid = peripheral.description().cString()
        if self.callback:
            self.callback(rssi.intValue(), name, sensor)
        else:
            print uuid, name, sensor, rssi
        if uuid not in self.peripherals:
            pass
            #self.connect(peripheral)
        self.peripherals[name] = (peripheral, rssi)


    @protocol('CBCentralManagerDelegate')
    def centralManager_didConnectPeripheral_(self, central, peripheral):
        if not peripheral.name.UTF8String():
            return
        peripheral.delegate = self
        CBUUID = autoclass('CBUUID')
        service = CBUUID.UUIDWithString_('1901')
        peripheral.discoverServices_([service])

    @protocol('CBPeripheralDelegate')
    def peripheral_didDiscoverServices_(self, peripheral, error):
        for i in range(peripheral.services.count()):
            service = peripheral.services.objectAtIndex_(i)
            if service.UUID.UUIDString.cString() == '1901':
                break
        else:
            assert(0)
        peripheral.discoverCharacteristics_forService_([], service)

    @protocol('CBPeripheralDelegate')
    def peripheral_didDiscoverCharacteristicsForService_error_(self, peripheral, service, error):
        print "discovered characteristic: ", service, service.characteristics
        for i in range(service.characteristics.count()):
            ch = service.characteristics.objectAtIndex_(i)
            if ch.UUID.UUIDString.cString() == '2B01':
                peripheral.setNotifyValue_forCharacteristic_(True, ch)
                print "set notify for chr {}".format(i)

    @protocol('CBPeripheralDelegate')
    def peripheral_didUpdateNotificationStateForCharacteristic_error_(
            self, peripheral, characteristic, error):
        # probably needs to decode like for advertising
        # sensor = c.get_from_ptr(values.bytes().arg_ref, 'c', values.length())
        print "characteristic: {} notifying: {}".format(characteristic.UUID.UUIDString.cString(), characteristic.isNotifying)
        pass

    @protocol('CBPeripheralDelegate')
    def peripheral_didUpdateValueForCharacteristic_error_(self, peripheral, characteristic, error):
        # probably needs to decode like for advertising
        # sensor = c.get_from_ptr(values.bytes().arg_ref, 'c', values.length())
        data =  c.get_from_ptr(characteristic.value.bytes().arg_ref, 'c', characteristic.value.length())
        name = peripheral.name.cString()
        peripheral.readRSSI()
        rssi = peripheral.RSSI and peripheral.RSSI.intValue() or 0
        if self.callback:
            if self.queue is not None:
                self.queue.append((rssi, name, data))

            else:
                self.callback(rssi, name, data)
        else:
            print name, rsii, data

Answer 1

这意味着您的协议(protocol)方法之一存在错误，例如 centralManager_didDiscoverPeripheral_advertisementData_RSSI_()。但您没有提供任何代码。

我现在也更新了我的 plyer BLE 代码 - 它支持连接和基本的特征读取/写入。这是一项正在进行中的工作，代码相当困惑，因为它是我的 BLE 测试和学习环境。您可以在这里查看:https://github.com/kivy/plyer/pull/185

如果您尝试为此编写自己的代码，请记住以下几点。首先，确保在连接时保留对 CBPeripheral 对象的引用 - 否则该对象将被释放，并且您的连接将默默失败。其次，确保通过 peripheral.setDelegate_(self) 设置 CBPeripheralDelegate 而不是 peripheral.delegate = self - 后者将不起作用，并且您的协议(protocol)方法将不会被调用。最后，pyobjus 中存在一个将字节传递给 void* 参数的错误 - 这将阻止您创建二进制 NSData 对象来读取/写入特征值。不过，我有一个针对该错误的 PR ( https://github.com/kivy/pyobjus/pull/26 )。