android - 在BLE android中写一个特性

Question

我正在尝试将 BLE android 中的特征发送到另一台设备。

在互联网上搜索我找到了一些可以帮助我做到这一点的代码，但我无法成功传输数据。

这是我的代码，基于 Gatt android 示例项目：

public class DeviceControlActivity extends Activity {

public static final String EXTRAS_DEVICE_NAME = "DEVICE_NAME";
public static final String EXTRAS_DEVICE_ADDRESS = "DEVICE_ADDRESS";

private TextView mConnectionState;
private TextView mDataField;
private TextView mRssiField;
private String mDeviceName;
private String mDeviceAddress;
private ExpandableListView mGattServicesList;
private BluetoothLeService mBluetoothLeService;
private ArrayList<ArrayList<BluetoothGattCharacteristic>> mGattCharacteristics =
        new ArrayList<ArrayList<BluetoothGattCharacteristic>>();
private boolean mConnected = false;
private BluetoothGattCharacteristic mNotifyCharacteristic;
private BluetoothGattCharacteristic mWriteCharacteristic;

private final String LIST_NAME = "NAME";
private final String LIST_UUID = "UUID";

BluetoothGattCharacteristic characteristic;

public BluetoothGatt mBluetoothGatt;
// Code to manage Service lifecycle.
private final ServiceConnection mServiceConnection = new ServiceConnection() {

    @Override
    public void onServiceConnected(ComponentName componentName, IBinder service) {
        mBluetoothLeService = ((BluetoothLeService.LocalBinder) service).getService();
        if (!mBluetoothLeService.initialize()) {
            Log.e("Unable to initialize Bluetooth");
            finish();
        }
        // Automatically connects to the device upon successful start-up initialization.
        mBluetoothLeService.connect(mDeviceAddress);
        mBluetoothLeService.setBLEServiceCb(mDCServiceCb);
    }

    @Override
    public void onServiceDisconnected(ComponentName componentName) {
        mBluetoothLeService = null;
    }
};

// If a given GATT characteristic is selected, check for supported features.  This sample
// demonstrates 'Read' and 'Notify' features.  See
// http://d.android.com/reference/android/bluetooth/BluetoothGatt.html for the complete
// list of supported characteristic features.
private final ExpandableListView.OnChildClickListener servicesListClickListner =
        new ExpandableListView.OnChildClickListener() {
            @TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR2)
            @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();
                    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.
                        Log.d("BluetoothGattCharacteristic has PROPERTY_READ, so send read request");

                        if (mNotifyCharacteristic != null) {
                            mBluetoothLeService.setCharacteristicNotification(
                                    mNotifyCharacteristic, false);
                            mNotifyCharacteristic = null;
                        }
                        mBluetoothLeService.readCharacteristic(characteristic);
                    }

                    if ((charaProp & BluetoothGattCharacteristic.PROPERTY_NOTIFY) > 0) {
                        Log.d("BluetoothGattCharacteristic has PROPERTY_NOTIFY, so send notify request");

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

                    if (((charaProp & BluetoothGattCharacteristic.PROPERTY_WRITE) |
                            (charaProp & BluetoothGattCharacteristic.PROPERTY_WRITE_NO_RESPONSE)) > 0) {
                        Log.d("BluetoothGattCharacteristic has PROPERY_WRITE | PROPERTY_WRITE_NO_RESPONSE");

                        mWriteCharacteristic = characteristic;
                        // popup an dialog to write something.
                        showCharactWriteDialog();
                    }
                    return true;
                }
                return false;
            }
};

private void showCharactWriteDialog() {
    DialogFragment newFrame = new BleCharacterDialogFragment();
    newFrame.show(getFragmentManager(), "blewrite");
}

private void clearUI() {
    mGattServicesList.setAdapter((SimpleExpandableListAdapter) null);
    mDataField.setText(R.string.no_data);
}

@TargetApi(Build.VERSION_CODES.HONEYCOMB)
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.gatt_services_characteristics);

    final Intent intent = getIntent();
    mDeviceName = intent.getStringExtra(EXTRAS_DEVICE_NAME);
    mDeviceAddress = intent.getStringExtra(EXTRAS_DEVICE_ADDRESS);

    // Sets up UI references.
    ((TextView) findViewById(R.id.device_address)).setText(mDeviceAddress);
    mGattServicesList = (ExpandableListView) findViewById(R.id.gatt_services_list);
    mGattServicesList.setOnChildClickListener(servicesListClickListner);
    mConnectionState = (TextView) findViewById(R.id.connection_state);
    mDataField = (TextView) findViewById(R.id.data_value);
    mRssiField = (TextView) findViewById(R.id.signal_rssi);

    getActionBar().setTitle(mDeviceName);
    getActionBar().setDisplayHomeAsUpEnabled(true);
    Intent gattServiceIntent = new Intent(this, BluetoothLeService.class);
    bindService(gattServiceIntent, mServiceConnection, BIND_AUTO_CREATE);
}

@Override
protected void onResume() {
    super.onResume();
    //registerReceiver(mGattUpdateReceiver, makeGattUpdateIntentFilter());
    if (mBluetoothLeService != null) {
        final boolean result = mBluetoothLeService.connect(mDeviceAddress);
        Log.d("Connect request result=" + result);
    }
}

@Override
protected void onPause() {
    super.onPause();
    //unregisterReceiver(mGattUpdateReceiver);
}

@Override
protected void onDestroy() {
    super.onDestroy();
    unbindService(mServiceConnection);
    mBluetoothLeService = null;
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.gatt_services, menu);
    if (mConnected) {
        menu.findItem(R.id.menu_connect).setVisible(false);
        menu.findItem(R.id.menu_disconnect).setVisible(true);
    } else {
        menu.findItem(R.id.menu_connect).setVisible(true);
        menu.findItem(R.id.menu_disconnect).setVisible(false);
    }
    return true;
}

@TargetApi(Build.VERSION_CODES.ECLAIR)
@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch(item.getItemId()) {
        case R.id.menu_connect:
            mBluetoothLeService.connect(mDeviceAddress);
            return true;
        case R.id.menu_disconnect:
            mBluetoothLeService.disconnect();
            return true;
        case android.R.id.home:
            onBackPressed();
            return true;
    }
    return super.onOptionsItemSelected(item);
}

private void updateConnectionState(final int resourceId) {
    runOnUiThread(new Runnable() {
        @Override
        public void run() {
            mConnectionState.setText(resourceId);
        }
    });
}

private void displayData(String data) {
    if (data != null) {
        mDataField.setText(data);
    }
}

private void displayRssi(String rssi) {
    if (rssi != null) {
        //Log.d("-- dispaly Rssi: " + rssi);
        mRssiField.setText(rssi);
    }
}
// Demonstrates how to iterate through the supported GATT Services/Characteristics.
// In this sample, we populate the data structure that is bound to the ExpandableListView
// on the UI.
@TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR2)
private void displayGattServices(List<BluetoothGattService> gattServices) {
    Log.d("displayGATTServices");

    if (gattServices == null) return;
    String uuid = null;
    String unknownServiceString = getResources().getString(R.string.unknown_service);
    String unknownCharaString = getResources().getString(R.string.unknown_characteristic);
    ArrayList<HashMap<String, String>> gattServiceData = new ArrayList<HashMap<String, String>>();
    ArrayList<ArrayList<HashMap<String, String>>> gattCharacteristicData
            = new ArrayList<ArrayList<HashMap<String, String>>>();
    mGattCharacteristics = new ArrayList<ArrayList<BluetoothGattCharacteristic>>();

    // Loops through available GATT Services.
    for (BluetoothGattService gattService : gattServices) {
        HashMap<String, String> currentServiceData = new HashMap<String, String>();
        uuid = gattService.getUuid().toString();
        currentServiceData.put(
                LIST_NAME, SampleGattAttributes.lookup(uuid, unknownServiceString));
        currentServiceData.put(LIST_UUID, uuid);
        gattServiceData.add(currentServiceData);

        ArrayList<HashMap<String, String>> gattCharacteristicGroupData =
                new ArrayList<HashMap<String, String>>();
        List<BluetoothGattCharacteristic> gattCharacteristics =
                gattService.getCharacteristics();
        ArrayList<BluetoothGattCharacteristic> charas =
                new ArrayList<BluetoothGattCharacteristic>();

        // Loops through available Characteristics.
        for (BluetoothGattCharacteristic gattCharacteristic : gattCharacteristics) {
            charas.add(gattCharacteristic);
            HashMap<String, String> currentCharaData = new HashMap<String, String>();
            uuid = gattCharacteristic.getUuid().toString();
            currentCharaData.put(
                    LIST_NAME, SampleGattAttributes.lookup(uuid, unknownCharaString));
            currentCharaData.put(LIST_UUID, uuid);
            gattCharacteristicGroupData.add(currentCharaData);
        }
        mGattCharacteristics.add(charas);
        gattCharacteristicData.add(gattCharacteristicGroupData);
    }

    SimpleExpandableListAdapter gattServiceAdapter = new SimpleExpandableListAdapter(
            this,
            gattServiceData,
            android.R.layout.simple_expandable_list_item_2,
            new String[] {LIST_NAME, LIST_UUID},
            new int[] { android.R.id.text1, android.R.id.text2 },
            gattCharacteristicData,
            android.R.layout.simple_expandable_list_item_2,
            new String[] {LIST_NAME, LIST_UUID},
            new int[] { android.R.id.text1, android.R.id.text2 }
    );
    mGattServicesList.setAdapter(gattServiceAdapter);
}

private DCServiceCb mDCServiceCb = new DCServiceCb();

public class DCServiceCb implements BluetoothLeService.BLEServiceCallback {

    @Override
    public void displayRssi(final int rssi) {
        runOnUiThread(new Runnable() {
              @Override
              public void run() {
                  DeviceControlActivity.this.displayRssi(String.valueOf(rssi));
                }
            }
        );
    }

    @Override
    public void displayData(final String data) {
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                DeviceControlActivity.this.displayData(data);
            }
        });
    }

    @Override
    public void notifyConnectedGATT() {
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                mConnected = true;
                updateConnectionState(R.string.connected);
                invalidateOptionsMenu();
            }
        });
    }

    @Override
    public void notifyDisconnectedGATT() {
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                mConnected = false;
                updateConnectionState(R.string.disconnected);
                invalidateOptionsMenu();
                clearUI();
            }
        });
    }

    @Override
    public void displayGATTServices() {
        Log.d("displayGATTServices.");
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                if (mBluetoothLeService != null) {
                    DeviceControlActivity.this.displayGattServices(
                            mBluetoothLeService.getSupportedGattServices());
                }
            }
        });
    }
}

@SuppressLint("ValidFragment")
public class BleCharacterDialogFragment extends DialogFragment {

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.write_charact_dialog, container, false);
        final EditText ed = (EditText) v.findViewById(R.id.charact_value);
        Button ok = (Button) v.findViewById(R.id.dialog_confirm);
        Button cancel = (Button) v.findViewById(R.id.dialog_cancel);

        ok.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                characteristic.setValue(new byte[] {0x02});
                writeCharacteristicValue(characteristic);

                Toast.makeText(getApplicationContext(), "Se envío el dato",
                        Toast.LENGTH_SHORT).show();
                dismiss();
                return;
            }
        });

        cancel.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                dismiss();
            }
        });

        return v;
    }
}

public void writeCharacteristicValue(BluetoothGattCharacteristic characteristica)
{
    byte[] value= {(byte) 0xFF};
    characteristica.setValue(bytesToHex(value));
    boolean status = mBluetoothGatt.writeCharacteristic(characteristica);
}

final protected static char[] hexArray = "0123456789ABCDEF".toCharArray();

public String bytesToHex(byte[] bytes) 
{
    char[] hexChars = new char[bytes.length * 2];
    int v;
    for ( int j = 0; j < bytes.length; j++ ) 
    {
        v = bytes[j] & 0xFF;
        hexChars[j * 2] = hexArray[v >>> 4];
        hexChars[j * 2 + 1] = hexArray[v & 0x0F];
    }
    return new String(hexChars);
}

}

这个想法是用户连接到蓝牙并触摸最后一个服务。然后如果输入一个文本并按下 OK，在蓝牙设备中写入一个特性。但是当我这样做时，出现一个错误说：E/AndroidRuntime(17427): Process: com.example.ble, PID: 17427 E/AndroidRuntime(17427): java.lang.RuntimeException: Unable to start activity ComponentInfo{com .example.ble/com.example.ble.DeviceControlActivity}：android.app.Fragment$InstantiationException：无法实例化片段com.example.ble.DeviceControlActivity$BleCharacterDialogFragment：确保类名存在，是公共的，并且有一个空的构造函数那是公开的

我没有任何使用 BLE 的经验，所以我对此一无所知。如果有人可以帮助我解决问题或共享执行此操作的完整代码。

感谢提前

android - 在BLE android中写一个特性

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