我正在开发一个Android应用程序，它将与与目标板（微控制器）连接的BLE设备（RN4020）进行通信。我开发了能够通过RN4020将数据发送到目标板并通过UART成功接收的应用程序。但是我无法从目标设备接收数据到应用程序。我每隔一秒从微控制器发送数据。但是从Play商店下载的应用 MLDP perminal 可以同时发送和接收数据。
调试时无法访问 onCharacteristicRead 。
如何从设备接收数据到应用程序？
package com.example.designemb5.tempworking;
import android.Manifest;
import android.app.AlertDialog;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothGatt;
import android.bluetooth.BluetoothGattCallback;
import android.bluetooth.BluetoothGattCharacteristic;
import android.bluetooth.BluetoothGattService;
import android.bluetooth.BluetoothManager;
import android.bluetooth.BluetoothProfile;
import android.bluetooth.le.BluetoothLeScanner;
import android.bluetooth.le.ScanCallback;
import android.bluetooth.le.ScanResult;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.os.AsyncTask;
import android.os.Build;
import android.os.Bundle;
import android.os.ParcelUuid;
import android.support.annotation.RequiresApi;
import android.support.v7.app.AppCompatActivity;
import android.text.method.ScrollingMovementMethod;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import java.util.List;
import java.util.Map;
import java.util.Timer;
import java.util.TimerTask;
import java.util.UUID;
public class MainActivity extends AppCompatActivity {
BluetoothManager btManager;
BluetoothAdapter btAdapter;
BluetoothLeScanner btScanner;
BluetoothDevice mBluetoothDevice;
public BluetoothAdapter mBluetoothAdapter;
public BluetoothGatt mBluetoothGatt;
public BluetoothGattService mBluetoothGattService;
private int mConnectionState = STATE_DISCONNECTED;
private BluetoothGattCharacteristic mWriteCharacteristic;
private static final int STATE_DISCONNECTED = 0;
private static final int STATE_CONNECTING = 1;
private static final int STATE_CONNECTED = 2;
Button startScanningButton;
Button stopScanningButton;
Button connectButton;
Button disconnectButton;
public boolean mConnected = false;
public boolean mCharacteristics = true;
private static final String TAG = "BLUETOOTH_LE";
public static List<ParcelUuid> MY_UUID;
public final static String ACTION_GATT_CONNECTED = "com.example.designemb5.tempworking.ACTION_GATT_CONNECTED";
public final static String ACTION_GATT_DISCONNECTED = "com.example.designemb5.tempworking.ACTION_GATT_DISCONNECTED";
public final static String ACTION_GATT_SERVICES_DISCOVERED = "com.example.designemb5.tempworking.ACTION_GATT_SERVICES_DISCOVERED";
public final static String ACTION_DATA_AVAILABLE = "com.example.designemb5.tempworking.ACTION_DATA_AVAILABLE";
public final static String EXTRA_DATA = "com.example.designemb5.tempworking.EXTRA_DATA";
public final static UUID MY_UUID_RN4020_SERVICE = UUID.fromString("00035b03-58e6-07dd-021a-08123a000300");
public final static UUID MY_UUID_RN4020_CHARACTERISTIC_WRITE = UUID.fromString("00035b03-58e6-07dd-021a-08123a000301");
public final static UUID MY_UUID_RN4020_CHARACTERISTIC_READ = UUID.fromString("00035b03-58e6-07dd-021a-08123a0003ff");
TextView peripheralTextView;
private final static int REQUEST_ENABLE_BT = 1;
private static final int PERMISSION_REQUEST_COARSE_LOCATION = 1;
public String mDeviceAddress;
public int mTestVal = 1;
public static Map<ParcelUuid, byte[]> mDeviceData;
@RequiresApi(api = Build.VERSION_CODES.M)
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
connectButton = (Button) findViewById(R.id.ConnectButton);
disconnectButton = (Button) findViewById(R.id.disonnectButton);
peripheralTextView = (TextView) findViewById(R.id.PeripheralTextView);
peripheralTextView.setMovementMethod(new ScrollingMovementMethod());
startScanningButton = (Button) findViewById(R.id.StartScanButton);
startScanningButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
startScanning();
}
});
stopScanningButton = (Button) findViewById(R.id.StopScanButton);
stopScanningButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
stopScanning();
}
});
stopScanningButton.setVisibility(View.INVISIBLE);
btManager = (BluetoothManager)getSystemService(Context.BLUETOOTH_SERVICE);
btAdapter = btManager.getAdapter();
btScanner = btAdapter.getBluetoothLeScanner();
if (btAdapter != null && !btAdapter.isEnabled()) {
Intent enableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableIntent,REQUEST_ENABLE_BT);
}
// Make sure we have access coarse location enabled, if not, prompt the user to enable it
if (this.checkSelfPermission(Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
final AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("This app needs location access");
builder.setMessage("Please grant location access so this app can detect peripherals.");
builder.setPositiveButton(android.R.string.ok, null);
builder.setOnDismissListener(new DialogInterface.OnDismissListener() {
@Override
public void onDismiss(DialogInterface dialog) {
requestPermissions(new String[]{Manifest.permission.ACCESS_COARSE_LOCATION}, PERMISSION_REQUEST_COARSE_LOCATION);
}
});
builder.show();
}
}
public void startScanning() {
System.out.println("start scanning");
peripheralTextView.setText("");
startScanningButton.setVisibility(View.INVISIBLE);
stopScanningButton.setVisibility(View.VISIBLE);
AsyncTask.execute(new Runnable() {
@Override
public void run() {
btScanner.startScan(leScanCallback);
}
});
}
public void stopScanning() {
System.out.println("stopping scanning");
peripheralTextView.append("Stopped Scanning");
startScanningButton.setVisibility(View.VISIBLE);
stopScanningButton.setVisibility(View.INVISIBLE);
AsyncTask.execute(new Runnable() {
@Override
public void run() {
btScanner.stopScan(leScanCallback);
}
});
}
public void connect(View view) {
connectButton.setVisibility(View.INVISIBLE);
disconnectButton.setVisibility(View.VISIBLE);
final BluetoothManager bluetoothManager =
(BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
mBluetoothAdapter = bluetoothManager.getAdapter();
final BluetoothDevice device = btAdapter
.getRemoteDevice(mDeviceAddress);
mBluetoothGatt = device.connectGatt(this, false, mGattCallback);
}
public void disconnect(View view) {
connectButton.setVisibility(View.VISIBLE);
disconnectButton.setVisibility(View.INVISIBLE);
mBluetoothGatt.disconnect();
}
public void senddata(View view) {
{
int value = 0x01;
if (mBluetoothAdapter == null || mBluetoothGatt == null) {
Log.w(TAG, "BluetoothAdapter not initialized");
return;
}
/*check if the service is available on the device*/
BluetoothGattService mCustomService = mBluetoothGatt.getService(MY_UUID_RN4020_SERVICE);
if (mCustomService == null) {
Log.w(TAG, "Custom BLE Service not found");
return;
}
/*get the read characteristic from the service*/
BluetoothGattCharacteristic mWriteCharacteristic = mCustomService.getCharacteristic(MY_UUID_RN4020_CHARACTERISTIC_WRITE);
mWriteCharacteristic.setValue(value, BluetoothGattCharacteristic.FORMAT_UINT8, 0);
if (mBluetoothGatt.writeCharacteristic(mWriteCharacteristic) == false) {
Log.w(TAG, "Failed to write characteristic");
}
}
}
public void receivedata(View view) {
{
if (mBluetoothAdapter == null || mBluetoothGatt == null) {
Log.w(TAG, "BluetoothAdapter not initialized");
return;
}
/*check if the service is available on the device*/
BluetoothGattService mCustomService = mBluetoothGatt.getService(MY_UUID_RN4020_SERVICE);
if (mCustomService == null) {
Log.w(TAG, "Custom BLE Service not found");
return;
}
BluetoothGattCharacteristic mReadCharacteristic = mCustomService.getCharacteristic(MY_UUID_RN4020_CHARACTERISTIC_READ);
if (mBluetoothGatt.readCharacteristic(mReadCharacteristic) == false) {
Log.w(TAG, "Failed to read characteristic");
}
mBluetoothGatt.readCharacteristic(mReadCharacteristic);
}
}
// Device scan callback.
private ScanCallback leScanCallback = new ScanCallback() {
@Override
public void onScanResult(int callbackType, ScanResult result) {
processResult(result);
}
private void processResult(ScanResult result){
mBluetoothDevice = result.getDevice();
mDeviceAddress = result.getDevice().getAddress();
mDeviceData = result.getScanRecord().getServiceData();
MY_UUID = result.getScanRecord().getServiceUuids();
peripheralTextView.append("Device Name: " + mDeviceAddress + "\n");
stopScanning();
}
};
private final BluetoothGattCallback mGattCallback = new BluetoothGattCallback() {
@Override
public void onCharacteristicWrite(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) {
super.onCharacteristicWrite(gatt, characteristic, status);
// updateStatus(characteristic);
Log.e("gatt", "writeChar");
}
@Override
public void onConnectionStateChange(BluetoothGatt gatt, int status,
int newState) {
String intentAction;
if (newState == BluetoothProfile.STATE_CONNECTED) {
intentAction = ACTION_GATT_CONNECTED;
mConnectionState = STATE_CONNECTED;
broadcastUpdate(intentAction);
Log.i(TAG, "Connected to GATT server.");
// Attempts to discover services after successful connection.
Log.i(TAG, "Attempting to start service discovery:"
+ mBluetoothGatt.discoverServices());
TimerTask task = new TimerTask() {
@Override
public void run() {
if (mBluetoothGatt != null)
mBluetoothGatt.readRemoteRssi();
}
};
Timer mRssiTimer = new Timer();
mRssiTimer.schedule(task, 1000, 1000);
} else if (newState == BluetoothProfile.STATE_DISCONNECTED) {
intentAction = ACTION_GATT_DISCONNECTED;
mConnectionState = STATE_DISCONNECTED;
Log.i(TAG, "Disconnected from GATT server.");
broadcastUpdate(intentAction);
}
}
@Override
public void onServicesDiscovered(BluetoothGatt gatt, int status) {
if (status == BluetoothGatt.GATT_SUCCESS) {
broadcastUpdate(ACTION_GATT_SERVICES_DISCOVERED);
} else {
Log.w(TAG, "onServicesDiscovered received: " + status);
}
BluetoothGattService mCustomService = mBluetoothGatt.getService(MY_UUID_RN4020_SERVICE);
BluetoothGattCharacteristic mReadCharacteristic = mCustomService.getCharacteristic(MY_UUID_RN4020_CHARACTERISTIC_READ);
gatt.readCharacteristic(mReadCharacteristic);
gatt.setCharacteristicNotification(mReadCharacteristic, true);
}
@Override
public void onCharacteristicRead(BluetoothGatt gatt,
BluetoothGattCharacteristic characteristic, int status) {
if (status == BluetoothGatt.GATT_SUCCESS) {
gatt.readCharacteristic(characteristic);
broadcastUpdate(ACTION_DATA_AVAILABLE, characteristic);
}
}
@Override
public void onCharacteristicChanged(BluetoothGatt gatt,
BluetoothGattCharacteristic characteristic) {
broadcastUpdate(ACTION_DATA_AVAILABLE, characteristic);
}
};
@Override
public void onRequestPermissionsResult(int requestCode,
String permissions[], int[] grantResults) {
switch (requestCode) {
case PERMISSION_REQUEST_COARSE_LOCATION: {
if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
System.out.println("coarse location permission granted");
} else {
final AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("Functionality limited");
builder.setMessage("Since location access has not been granted, this app will not be able to discover beacons when in the background.");
builder.setPositiveButton(android.R.string.ok, null);
builder.setOnDismissListener(new DialogInterface.OnDismissListener() {
@Override
public void onDismiss(DialogInterface dialog) {
}
});
builder.show();
}
return;
}
}
}
public void writeCharacteristic(BluetoothGattCharacteristic characteristic) {
mBluetoothGatt.writeCharacteristic(characteristic);
}
private void broadcastUpdate(final String action) {
final Intent intent = new Intent(action);
sendBroadcast(intent);
}
private void broadcastUpdate(final String action,
final BluetoothGattCharacteristic characteristic) {
final Intent intent = new Intent(action);
// This is special handling for the Heart Rate Measurement profile. Data
// parsing is
// carried out as per profile specifications:
// http://developer.bluetooth.org/gatt/characteristics/Pages/CharacteristicViewer.aspx?u=org.bluetooth.characteristic.heart_rate_measurement.xml
/* if (UUID_HEART_RATE_MEASUREMENT.equals(characteristic.getUuid())) {
int flag = characteristic.getProperties();
int format = -1;
if ((flag & 0x01) != 0) {
format = BluetoothGattCharacteristic.FORMAT_UINT16;
Log.d(TAG, "Heart rate format UINT16.");
} else {
format = BluetoothGattCharacteristic.FORMAT_UINT8;
Log.d(TAG, "Heart rate format UINT8.");
}
final int heartRate = characteristic.getIntValue(format, 1);
Log.d(TAG, String.format("Received heart rate: %d", heartRate));
intent.putExtra(EXTRA_DATA, String.valueOf(heartRate));
} else {
// For all other profiles, writes the data formatted in HEX.
final byte[] data = characteristic.getValue();
if (data != null && data.length > 0) {
final StringBuilder stringBuilder = new StringBuilder(
data.length);
for (byte byteChar : data)
stringBuilder.append(String.format("%02X ", byteChar));
intent.putExtra(EXTRA_DATA, new String(data) + "\n"
+ stringBuilder.toString());
}
}*/
final byte[] data = characteristic.getValue();
Log.v(TAG, "data.length: " + data.length);
if (data != null && data.length > 0) {
final StringBuilder stringBuilder = new StringBuilder(data.length);
for(byte byteChar : data) {
stringBuilder.append(String.format("%02X ", byteChar));
Log.v(TAG, String.format("%02X ", byteChar));
}
intent.putExtra(EXTRA_DATA, new String(data) + "\n" + stringBuilder.toString());
}
sendBroadcast(intent);
}
private void showMessage(String str){
Toast.makeText(MainActivity.this, str, Toast.LENGTH_SHORT).show();
}
}
答案 0 :(得分：1)
启用通知：
gatt.setCharacteristicNotification(yourCharacteristic, true);
BluetoothGattDescriptor desc = yourCharacteristic.getDescriptor(UUID);
然后：
desc.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
gatt.writeDescriptor(desc);
执行此操作后，每次发送数据时都应调用onCharacteristicChanged（）。通过重写onDescriptorWrite（）方法确认启用通知是否成功。