Android studio 带Android Studio的蓝牙LE：带按钮的写入特性

我对安卓和蓝牙还不熟悉，正为这个问题苦恼

如果触摸两个按钮，我想写一个特定的特征。 如果我按下第一个按钮，0-9之间的数字应为+1。使用另一个按钮，数字应减少为-1。 作为基础，我使用谷歌的BlueTootletegat示例应用程序。 在DeviceControlActivity中，我更改了以下代码：

private final ExpandableListView.OnChildClickListener servicesListClickListner =
        new ExpandableListView.OnChildClickListener() {
            @Override
            public boolean onChildClick(ExpandableListView parent, View v, int groupPosition,
                                        int childPosition, long id) {
                if (mGattCharacteristics != null) {
                    final BluetoothGattCharacteristic characteristic =
                            mGattCharacteristics.get(groupPosition).get(childPosition);
                    final int charaProp = characteristic.getProperties();  //The properties contain a bit mask of property flags indicating
                   //the features of this characteristic.
                   if ((charaProp | BluetoothGattCharacteristic.PROPERTY_READ) > 0) {
                        // If there is an active notification on a characteristic, clear
                        // it first so it doesn't update the data field on the user interface.
                        if (mNotifyCharacteristic != null) {
                            mBluetoothLeService.setCharacteristicNotification(
                                    mNotifyCharacteristic, false);
                            mNotifyCharacteristic = null;
                        }
                      mBluetoothLeService.readCharacteristic(characteristic);
                    }
                    if ((charaProp | BluetoothGattCharacteristic.PROPERTY_NOTIFY ) > 0) {

                        mNotifyCharacteristic = characteristic;
                        mBluetoothLeService.setCharacteristicNotification(
                                characteristic, true);
                    }

                    if ((charaProp | BluetoothGattCharacteristic.PROPERTY_WRITE) > 0) {
                        characteristic.setWriteType(BluetoothGattCharacteristic.PERMISSION_WRITE);
                        addListenerOnButton();

                    }

                    return true;
                }
                return false;
            }
};

以下是我的addListenerOnButton（）用于两个按钮：

public void addListenerOnButton() {

    mArrowUp = (ImageButton) findViewById(R.id.arrow_up);
    mArrowUp.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View arg0) {
          mBluetoothLeService.writeCharacteristicUp();

        }

    });

    mArrowDown = (ImageButton) findViewById(R.id.arrow_down);
    mArrowDown.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View arg0) {
        mBluetoothLeService.writeCharacteristicDown();
        }

    });

}

他们将调用BluetoothLeService类中的两个writeCharacteristic方法。例如，我在这里仅发布writeCharacteristicUp（）方法：

问题是

boolean status = mBluetoothGatt.writeCharacteristic(charac)  

如果不工作，状态将为false。因此，实际值不会显示在相应文本视图的屏幕上。为什么？

---

我还发现if研磨不工作，因为charac.setValue（value0）仅在if研磨之外工作？

我建议您按住control键，然后单击代码中的

BluetoothGatt#writeCharacteristic（ch）

函数。然后Android Studio将查看

BluetoothGatt#writeCharacteristic（BluetoothGattCharacteristic特征）

功能：

    public boolean writeCharacteristic(BluetoothGattCharacteristic characteristic) {
    if ((characteristic.getProperties() & BluetoothGattCharacteristic.PROPERTY_WRITE) == 0
        && (characteristic.getProperties() &
            BluetoothGattCharacteristic.PROPERTY_WRITE_NO_RESPONSE) == 0) return false;

    if (VDBG) Log.d(TAG, "writeCharacteristic() - uuid: " + characteristic.getUuid());
    if (mService == null || mClientIf == 0 || characteristic.getValue() == null) return false;

    BluetoothGattService service = characteristic.getService();
    if (service == null) return false;

    BluetoothDevice device = service.getDevice();
    if (device == null) return false;

    synchronized(mDeviceBusy) {
        if (mDeviceBusy) return false;
        mDeviceBusy = true;
    }

    try {
        mService.writeCharacteristic(mClientIf, device.getAddress(),
            service.getType(), service.getInstanceId(),
            new ParcelUuid(service.getUuid()), characteristic.getInstanceId(),
            new ParcelUuid(characteristic.getUuid()),
            characteristic.getWriteType(), AUTHENTICATION_NONE,
            characteristic.getValue());
    } catch (RemoteException e) {
        Log.e(TAG,"",e);
        mDeviceBusy = false;
        return false;
    }

    return true;
}

在方法中放置断点并进行调试。以下是根据源代码得到

false

的可能原因：

远程BLE设备没有写入或无响应写入访问权限

您的服务为null，或者您设置的特征值为null

您的设备已在使用远程设备执行另一个可恢复进程

在我看来，最有可能的第二项是原因

    public boolean writeCharacteristic(BluetoothGattCharacteristic characteristic) {
    if ((characteristic.getProperties() & BluetoothGattCharacteristic.PROPERTY_WRITE) == 0
        && (characteristic.getProperties() &
            BluetoothGattCharacteristic.PROPERTY_WRITE_NO_RESPONSE) == 0) return false;

    if (VDBG) Log.d(TAG, "writeCharacteristic() - uuid: " + characteristic.getUuid());
    if (mService == null || mClientIf == 0 || characteristic.getValue() == null) return false;

    BluetoothGattService service = characteristic.getService();
    if (service == null) return false;

    BluetoothDevice device = service.getDevice();
    if (device == null) return false;

    synchronized(mDeviceBusy) {
        if (mDeviceBusy) return false;
        mDeviceBusy = true;
    }

    try {
        mService.writeCharacteristic(mClientIf, device.getAddress(),
            service.getType(), service.getInstanceId(),
            new ParcelUuid(service.getUuid()), characteristic.getInstanceId(),
            new ParcelUuid(characteristic.getUuid()),
            characteristic.getWriteType(), AUTHENTICATION_NONE,
            characteristic.getValue());
    } catch (RemoteException e) {
        Log.e(TAG,"",e);
        mDeviceBusy = false;
        return false;
    }

    return true;
}