Question

我是一名学生正在做Android Things项目，该项目是关于连接Rasperi pi和Accelerometer传感器来获取加速度数据，我在Android Studio中完成了编码部分并且传感器工作正常，然后我尝试连接我的按照本教程投影到云端：http://blog.blundellapps.co.uk/tut-google-cloud-iot-core-mqtt-on-android/

我想我必须通过在MainActivity类中调用此方法将加速度计数据发布到云中，我这样做但仍然有错误，请参阅我在此问题结尾处执行的更新请。

@Override
    public void onSensorChanged(SensorEvent event) {
        Log.d(TAG, "Accel X " + event.values[0]);
        Log.d(TAG, "Accel Y " + event.values[1]);
        Log.d(TAG, "Accel Z " + event.values[2]);
    }

另外，我是否必须在云平台上执行某些操作才能接收数据？我已经使用我的Google IoT Core详细信息设置了通信，如下面的代码所示：

 communicator = new IotCoreCommunicator.Builder()
                .withContext(this)
                .withCloudRegion("us-central1") 
                .withProjectId("my-first-project-198704")  
                .withRegistryId("vibration") 
                .withDeviceId("my-device") 
                .withPrivateKeyRawFileId(R.raw.rsa_private)
                .build();

这就是我在云中看到的：

这是我在Android Studio中的加速数据：

我的项目包含两个模块，但在这里我只附加第二个模块，因为问题仅限于3000个字符，第二个模块是我想要编辑的内容。

示例模块：

AccelerometerActivity类：

package com.cacaosd.sample;

import android.app.Activity;
import android.content.Context;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.util.Log;

import com.cacaosd.adxl345.ADXL345SensorDriver;
import com.cacaosd.sample.BoardDefaults;

import java.io.IOException;

public class AccelerometerActivity extends Activity implements SensorEventListener {

    private static final String TAG = AccelerometerActivity.class.getSimpleName();

    private ADXL345SensorDriver mSensorDriver;
    private SensorManager mSensorManager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
        mSensorManager.registerDynamicSensorCallback(new SensorManager.DynamicSensorCallback() {
            @Override
            public void onDynamicSensorConnected(Sensor sensor) {
                if (sensor.getType() == Sensor.TYPE_ACCELEROMETER) {
                    mSensorManager.registerListener(AccelerometerActivity.this,
                            sensor, SensorManager.SENSOR_DELAY_NORMAL);
                }
            }


        });

        try {
            mSensorDriver = new ADXL345SensorDriver(BoardDefaults.getI2CPort());
            mSensorDriver.registerAccelerometerSensor();
        } catch (IOException e) {
            Log.e(TAG, "Error configuring sensor", e);
        }
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        Log.i(TAG, "Closing sensor");
        if (mSensorDriver != null) {
            mSensorManager.unregisterListener(this);
            try {
                mSensorDriver.close();
            } catch (IOException e) {
                Log.e(TAG, "Error closing sensor", e);
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                mSensorDriver = null;
            }
        }
    }

    @Override
    public void onSensorChanged(SensorEvent event) {
        Log.d(TAG, "Accel X " + event.values[0]);
        Log.d(TAG, "Accel Y " + event.values[1]);
        Log.d(TAG, "Accel Z " + event.values[2]);
    }



    @Override
    public void onAccuracyChanged(Sensor sensor, int accuracy) {
        Log.i(TAG, "sensor accuracy changed: " + accuracy);

    }
}

BoardDefaults类：

    package com.cacaosd.sample;

import android.os.Build;

import com.google.android.things.pio.PeripheralManagerService;

import java.util.List;

/**
 * Created by cagdas on 20.12.2016.
 */

@SuppressWarnings("WeakerAccess")
public class BoardDefaults {
    private static final String DEVICE_EDISON_ARDUINO = "edison_arduino";
    private static final String DEVICE_EDISON = "edison";
    private static final String DEVICE_RPI3 = "rpi3";
    private static final String DEVICE_NXP = "imx6ul";
    private static String sBoardVariant = "";

    /**
     * Return the preferred I2C port for each board.
     */
    public static String getI2CPort() {
        switch (getBoardVariant()) {
            case DEVICE_EDISON_ARDUINO:
                return "I2C6";
            case DEVICE_EDISON:
                return "I2C1";
            case DEVICE_RPI3:
                return "I2C1";
            case DEVICE_NXP:
                return "I2C2";
            default:
                throw new IllegalStateException("Unknown Build.DEVICE " + Build.DEVICE);
        }
    }

    private static String getBoardVariant() {
        if (!sBoardVariant.isEmpty()) {
            return sBoardVariant;
        }
        sBoardVariant = Build.DEVICE;
        // For the edison check the pin prefix
        // to always return Edison Breakout pin name when applicable.
        if (sBoardVariant.equals(DEVICE_EDISON)) {
            PeripheralManagerService pioService = new PeripheralManagerService();
            List<String> gpioList = pioService.getGpioList();
            if (gpioList.size() != 0) {
                String pin = gpioList.get(0);
                if (pin.startsWith("IO")) {
                    sBoardVariant = DEVICE_EDISON_ARDUINO;
                }
            }
        }
        return sBoardVariant;
    }
}

IotCoreCommunicator类：

    package com.cacaosd.sample1;

import android.content.Context;
import android.util.Log;

import java.util.concurrent.TimeUnit;

import org.eclipse.paho.android.service.MqttAndroidClient;
import org.eclipse.paho.client.mqttv3.IMqttActionListener;
import org.eclipse.paho.client.mqttv3.IMqttDeliveryToken;
import org.eclipse.paho.client.mqttv3.IMqttToken;
import org.eclipse.paho.client.mqttv3.MqttCallback;
import org.eclipse.paho.client.mqttv3.MqttConnectOptions;
import org.eclipse.paho.client.mqttv3.MqttException;
import org.eclipse.paho.client.mqttv3.MqttMessage;

public class IotCoreCommunicator {

    private static final String SERVER_URI = "ssl://mqtt.googleapis.com:8883";

    public static class Builder {

        private Context context;
        private String projectId;
        private String cloudRegion;
        private String registryId;
        private String deviceId;
        private int privateKeyRawFileId;

        public Builder withContext(Context context) {
            this.context = context;
            return this;
        }

        public Builder withProjectId(String projectId) {
            this.projectId = projectId;
            return this;
        }

        public Builder withCloudRegion(String cloudRegion) {
            this.cloudRegion = cloudRegion;
            return this;
        }

        public Builder withRegistryId(String registryId) {
            this.registryId = registryId;
            return this;
        }

        public Builder withDeviceId(String deviceId) {
            this.deviceId = deviceId;
            return this;
        }

        public Builder withPrivateKeyRawFileId(int privateKeyRawFileId) {
            this.privateKeyRawFileId = privateKeyRawFileId;
            return this;
        }

        public IotCoreCommunicator build() {
            if (context == null) {
                throw new IllegalStateException("context must not be null");
            }

            if (projectId == null) {
                throw new IllegalStateException("projectId must not be null");
            }
            if (cloudRegion == null) {
                throw new IllegalStateException("cloudRegion must not be null");
            }
            if (registryId == null) {
                throw new IllegalStateException("registryId must not be null");
            }
            if (deviceId == null) {
                throw new IllegalStateException("deviceId must not be null");
            }
            String clientId = "projects/" + projectId + "/locations/" + cloudRegion + "/registries/" + registryId + "/devices/" + deviceId;

            if (privateKeyRawFileId == 0) {
                throw new IllegalStateException("privateKeyRawFileId must not be 0");
            }
            MqttAndroidClient client = new MqttAndroidClient(context, SERVER_URI, clientId);
            IotCorePasswordGenerator passwordGenerator = new IotCorePasswordGenerator(projectId, context.getResources(), privateKeyRawFileId);
            return new IotCoreCommunicator(client, deviceId, passwordGenerator);
        }

    }

    private final MqttAndroidClient client;
    private final String deviceId;
    private final IotCorePasswordGenerator passwordGenerator;

    IotCoreCommunicator(MqttAndroidClient client, String deviceId, IotCorePasswordGenerator passwordGenerator) {
        this.client = client;
        this.deviceId = deviceId;
        this.passwordGenerator = passwordGenerator;
    }

    public void connect() {
        monitorConnection();
        clientConnect();
        subscribeToConfigChanges();
    }

    private void monitorConnection() {
        client.setCallback(new MqttCallback() {
            @Override
            public void connectionLost(Throwable cause) {
                Log.e("TUT", "connection lost", cause);
            }

            @Override
            public void messageArrived(String topic, MqttMessage message) throws Exception {
                Log.d("TUT", "message arrived " + topic + " MSG " + message);
                // You need to do something with messages when they arrive
            }

            @Override
            public void deliveryComplete(IMqttDeliveryToken token) {
                Log.d("TUT", "delivery complete " + token);
            }
        });
    }

    private void clientConnect() {
        try {
            MqttConnectOptions connectOptions = new MqttConnectOptions();
            // Note that the the Google Cloud IoT Core only supports MQTT 3.1.1, and Paho requires that we explicitly set this.
            // If you don't, the server will immediately close its connection to your device.
            connectOptions.setMqttVersion(MqttConnectOptions.MQTT_VERSION_3_1_1);

            // With Google Cloud IoT Core, the username field is ignored, however it must be set for the
            // Paho client library to send the password field. The password field is used to transmit a JWT to authorize the device.
            connectOptions.setUserName("unused-but-necessary");
            connectOptions.setPassword(passwordGenerator.createJwtRsaPassword());

            IMqttToken iMqttToken = client.connect(connectOptions);
            iMqttToken.setActionCallback(new IMqttActionListener() {
                @Override
                public void onSuccess(IMqttToken asyncActionToken) {
                    Log.d("TUT", "success, connected");
                }

                @Override
                public void onFailure(IMqttToken asyncActionToken, Throwable exception) {
                    Log.e("TUT", "failure, not connected", exception);
                }
            });
            iMqttToken.waitForCompletion(TimeUnit.SECONDS.toMillis(30));
            Log.d("TUT", "IoT Core connection established.");
        } catch (MqttException e) {
            throw new IllegalStateException(e);
        }
    }

    /**
     * Configuration is managed and sent from the IoT Core Platform
     */
    private void subscribeToConfigChanges() {
        try {
            client.subscribe("/devices/" + deviceId + "/config", 1);
        } catch (MqttException e) {
            throw new IllegalStateException(e);
        }
    }

    public void publishMessage(String subtopic, String message) {
        String topic = "/devices/" + deviceId + "/" + subtopic;
        String payload = "{msg:\"" + message + "\"}";
        MqttMessage mqttMessage = new MqttMessage(payload.getBytes());
        mqttMessage.setQos(1);
        try {
            client.publish(topic, mqttMessage);
            Log.d("TUT", "IoT Core message published. To topic: " + topic);
        } catch (MqttException e) {
            throw new IllegalStateException(e);
        }
    }

    public void disconnect() {
        try {
            Log.d("TUT", "IoT Core connection disconnected.");
            client.disconnect();
        } catch (MqttException e) {
            throw new IllegalStateException(e);
        }
    }

}

IotCorePasswordGenerator类：

    package com.cacaosd.sample1;

import android.content.res.Resources;
import android.util.Base64;

import java.io.IOException;
import java.io.InputStream;
import java.security.KeyFactory;
import java.security.NoSuchAlgorithmException;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.time.Duration;
import java.time.Instant;
import java.util.Date;

import io.jsonwebtoken.JwtBuilder;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;

class IotCorePasswordGenerator {

    private final String projectId;
    private final Resources resources;
    private final int privateKeyRawFileId;

    IotCorePasswordGenerator(String projectId, Resources resources, int privateKeyRawFileId) {
        this.projectId = projectId;
        this.resources = resources;
        this.privateKeyRawFileId = privateKeyRawFileId;
    }

    char[] createJwtRsaPassword() {
        try {
            byte[] privateKeyBytes = decodePrivateKey(resources, privateKeyRawFileId);
            return createJwtRsaPassword(projectId, privateKeyBytes).toCharArray();
        } catch (NoSuchAlgorithmException e) {
            throw new IllegalStateException("Algorithm not supported. (developer error)", e);
        } catch (InvalidKeySpecException e) {
            throw new IllegalStateException("Invalid Key spec. (developer error)", e);
        } catch (IOException e) {
            throw new IllegalStateException("Cannot read private key file.", e);
        }
    }

    private static byte[] decodePrivateKey(Resources resources, int privateKeyRawFileId) throws IOException {
        try(InputStream inStream = resources.openRawResource(privateKeyRawFileId)) {
            return Base64.decode(inputToString(inStream), Base64.DEFAULT);
        }
    }

    private static String inputToString(InputStream is) {
        java.util.Scanner s = new java.util.Scanner(is).useDelimiter("\\A");
        return s.hasNext() ? s.next() : "";
    }

    private static String createJwtRsaPassword(String projectId, byte[] privateKeyBytes) throws NoSuchAlgorithmException, InvalidKeySpecException {
        return createPassword(projectId, privateKeyBytes, "RSA", SignatureAlgorithm.RS256);
    }

    private static String createPassword(String projectId, byte[] privateKeyBytes, String algorithmName, SignatureAlgorithm signatureAlgorithm) throws NoSuchAlgorithmException, InvalidKeySpecException {
        Instant now = Instant.now();
        // Create a JWT to authenticate this device. The device will be disconnected after the token
        // expires, and will have to reconnect with a new token. The audience field should always be set
        // to the GCP project id.
        JwtBuilder jwtBuilder =
                Jwts.builder()
                        .setIssuedAt(Date.from(now))
                        .setExpiration(Date.from(now.plus(Duration.ofMinutes(20))))
                        .setAudience(projectId);

        PKCS8EncodedKeySpec spec = new PKCS8EncodedKeySpec(privateKeyBytes);
        KeyFactory kf = KeyFactory.getInstance(algorithmName);

        return jwtBuilder.signWith(signatureAlgorithm, kf.generatePrivate(spec)).compact();
    }

}


MainActivity class:

    package com.cacaosd.sample1;

import android.app.Activity;
import android.hardware.SensorEvent;
import android.os.Bundle;
import android.os.HandlerThread;
import android.os.Handler;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.HandlerThread;
import android.util.Log;


import com.cacaosd.sample.AccelerometerActivity;
import com.cacaosd.sample.R;
import com.cacaosd.sample1.IotCoreCommunicator;


import com.google.android.things.pio.Gpio;


import java.io.IOException;
import java.util.concurrent.TimeUnit;


public class MainActivity extends Activity {

    AccelerometerActivity mAccelerometerActivity = new AccelerometerActivity();

    private IotCoreCommunicator communicator;
    private Handler handler;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // Setup the communication with your Google IoT Core details
        communicator = new IotCoreCommunicator.Builder()
                .withContext(this)
                .withCloudRegion("us-central1") // ex: europe-west1
                .withProjectId("my-first-project-198704")   // ex: supercoolproject23236
                .withRegistryId("vibration") // ex: my-devices
                .withDeviceId("my-device") // ex: my-test-raspberry-pi
                .withPrivateKeyRawFileId(R.raw.rsa_private)
                .build();

        HandlerThread thread = new HandlerThread("MyBackgroundThread");
        thread.start();
        handler = new Handler(thread.getLooper());
        handler.post(connectOffTheMainThread); // Use whatever threading mechanism you want
    }

    private final Runnable connectOffTheMainThread = new Runnable() {
        @Override
        public void run() {
            communicator.connect();

            handler.post(sendMqttMessage);
        }
    };



    private final Runnable sendMqttMessage = new Runnable() {
        private int i;

        /**
         * We post 100 messages as an example, 1 a second
         */
        @Override
        public void run() {
            if (i == 100) {
                return;
            }

            SensorEvent event = null;

            // events is the default topic for MQTT communication
            String subtopic = "events";
            // Your message you want to send
            String message = "Hello World " + i++;
            communicator.publishMessage(subtopic, message);



            handler.postDelayed(this, TimeUnit.SECONDS.toMillis(1));
        }
    };

    @Override
    protected void onDestroy() {
        communicator.disconnect();
        super.onDestroy();
    }

MainActivity类：

package com.cacaosd.sample1;

import android.app.Activity;
import android.hardware.SensorEvent;
import android.os.Bundle;
import android.os.HandlerThread;
import android.os.Handler;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.HandlerThread;
import android.util.Log;


import com.cacaosd.sample.AccelerometerActivity;
import com.cacaosd.sample.R;
import com.cacaosd.sample1.IotCoreCommunicator;


import com.google.android.things.pio.Gpio;


import java.io.IOException;
import java.util.concurrent.TimeUnit;


public class MainActivity extends Activity {

    AccelerometerActivity mAccelerometerActivity = new AccelerometerActivity();

    private IotCoreCommunicator communicator;
    private Handler handler;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // Setup the communication with your Google IoT Core details
        communicator = new IotCoreCommunicator.Builder()
                .withContext(this)
                .withCloudRegion("us-central1") // ex: europe-west1
                .withProjectId("my-first-project-198704")   // ex: supercoolproject23236
                .withRegistryId("vibration") // ex: my-devices
                .withDeviceId("my-device") // ex: my-test-raspberry-pi
                .withPrivateKeyRawFileId(R.raw.rsa_private)
                .build();

        HandlerThread thread = new HandlerThread("MyBackgroundThread");
        thread.start();
        handler = new Handler(thread.getLooper());
        handler.post(connectOffTheMainThread); // Use whatever threading mechanism you want
    }

    private final Runnable connectOffTheMainThread = new Runnable() {
        @Override
        public void run() {
            communicator.connect();

            handler.post(sendMqttMessage);
        }
    };



    private final Runnable sendMqttMessage = new Runnable() {
        private int i;

        /**
         * We post 100 messages as an example, 1 a second
         */
        @Override
        public void run() {
            if (i == 100) {
                return;
            }

            SensorEvent event = null;

            // events is the default topic for MQTT communication
            String subtopic = "events";
            // Your message you want to send
            String message = "Hello World " + i++;
            communicator.publishMessage(subtopic, message);



            handler.postDelayed(this, TimeUnit.SECONDS.toMillis(1));
        }
    };

    @Override
    protected void onDestroy() {
        communicator.disconnect();
        super.onDestroy();
    }
}

更新

我在IotCoreCommunicator类中的publishMessage（）方法中添加了第三个输入（int加速），如下所示：

 public void publishMessage(String subtopic, String message, int acceleration) {
        String topic = "/devices/" + deviceId + "/" + subtopic;
        String payload = "{msg:\"" + message + "\"}";
        MqttMessage mqttMessage = new MqttMessage(payload.getBytes());
        mqttMessage.setQos(1);
        try {
            client.publish(topic, mqttMessage);
            Log.d("TUT", "IoT Core message published. To topic: " + topic);
        } catch (MqttException e) {
            throw new IllegalStateException(e);
        }
    }

然后我在MainActivity类中的run（）方法上调用它，如下所示：

 public void run() {
            if (i == 100) {
                return;
            }

            SensorEvent event = null;

            // events is the default topic for MQTT communication
            String subtopic = "events";
            // Your message you want to send
            String message = "Hello World " + i++;
            int acceleration = mAccelerometerActivity.onSensorChanged(SensorEvent event.values);
            communicator.publishMessage(subtopic, message, acceleration);



            handler.postDelayed(this, TimeUnit.SECONDS.toMillis(1));
        }
    };

但是我在下面的截图中仍然有这个错误：（';'或）预期）

此外，我添加的第三个输入显示为从未如您在下面的屏幕截图中看到的那样使用，这有什么影响吗？

谢谢。

如何从Android Studio发布和接收数据并将其放在Google Cloud IoT Core上？

0 个答案: