我现在有一个方法,它可以写入BLE设备来发出哔哔声。我的蓝牙回拨如下:
public class ReadWriteCharacteristic extends BluetoothGattCallback {
public ReadWriteCharacteristic(Context context, String macAddress, UUID service, UUID characteristic, Object tag, Activity activity) {
mMacAddress = macAddress;
mService = service;
mCharacteristic = characteristic;
mTag = tag;
mContext = context;
this.activity =activity;
final BluetoothManager bluetoothManager =
(BluetoothManager) mContext.getSystemService(Context.BLUETOOTH_SERVICE);
mBluetoothAdapter = bluetoothManager.getAdapter();
}
final private static String TAG = "ReadCharacteristic";
private Object mTag;
private String mMacAddress;
private UUID mService;
private BluetoothManager mBluetoothManager = null;
private BluetoothAdapter mBtAdapter = null;
private BluetoothGatt mBluetoothGatt = null;
private String mBluetoothDeviceAddress ="";
private UUID mCharacteristic;
BluetoothDevice device;
private Activity activity;
private BluetoothAdapter mBluetoothAdapter;
private Context mContext;
ReadWriteCharacteristic rc;
private int retry = 5;
public String getMacAddress() {
return mMacAddress;
}
public UUID getService() {
return mService;
}
public UUID getCharacteristic() {
return mCharacteristic;
}
public byte[] getValue() { return mValue; }
public void onError() {
Log.w(TAG, "onError");
}
public void readCharacteristic(){
if (retry == 0)
{
onError();
return;
}
retry--;
device = mBluetoothAdapter.getRemoteDevice(getMacAddress());
mBluetoothManager = (BluetoothManager) mContext.getSystemService(Context.BLUETOOTH_SERVICE);
int connectionState = mBluetoothManager.getConnectionState(device,
BluetoothProfile.GATT);
if (device != null) {
if (connectionState == BluetoothProfile.STATE_DISCONNECTED)
{
// Previously connected device. Try to reconnect.
if (mBluetoothDeviceAddress != null
&& getMacAddress().equals(mBluetoothDeviceAddress)
&& mBluetoothGatt != null) {
Log.w(TAG, "Re-use GATT connection");
if (mBluetoothGatt.connect()) {
Log.w(TAG, "Already connected, discovering services");
mBluetoothGatt.discoverServices();
//return ;
} else {
Log.w(TAG, "GATT re-connect failed.");
return;
}
}
if (device == null) {
Log.w(TAG, "Device not found. Unable to connect.");
return;
}
Log.w(TAG, "Create a new GATT connection.");
rc= ReadWriteCharacteristic.this;
Log.w(TAG, "Starting Read [" + getService() + "|" + getCharacteristic() + "]");
mBluetoothGatt = device.connectGatt(mContext, false, rc);
refreshDeviceCache(mBluetoothGatt);
mBluetoothDeviceAddress = getMacAddress();
} else {
Log.w(TAG, "Attempt to connect in state: " + connectionState);
if(mBluetoothGatt!=null)
mBluetoothGatt.close();
readCharacteristic();
}
}
}
@Override
public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
super.onConnectionStateChange(gatt, status, newState);
Log.w(TAG,"onConnectionStateChange [" + status + "|" + newState + "]");
if ((newState == 2)&&(status ==0)) {
gatt.discoverServices();
}
else if(status == 133 )
{
//gatt.disconnect();
gatt.close();
mBluetoothGatt = null;
try
{
Thread.sleep(2000);
}
catch(Exception e)
{
}
readCharacteristic();
}
else{
if(mBluetoothGatt!=null)
mBluetoothGatt.close();
// gatt.close();
Log.w(TAG, "[" + status + "]");
//gatt.disconnect();
try
{
Thread.sleep(2000);
}
catch(Exception e)
{
}
mBluetoothGatt = null;
readCharacteristic();
}
}
@Override
public void onServicesDiscovered(BluetoothGatt gatt, int status) {
Log.w(TAG,"onServicesDiscovered [" + status + "]");
BluetoothGattService bgs = gatt.getService(getService());
if (bgs != null) {
BluetoothGattCharacteristic bgc = bgs.getCharacteristic(getCharacteristic());
gatt.readCharacteristic(bgc);
}
}
@Override
public void onCharacteristicWrite(BluetoothGatt gatt,
BluetoothGattCharacteristic characteristic,
int status) {
Log.w(TAG,"onCharacteristicWrite [" + status + "]");
if (status == BluetoothGatt.GATT_SUCCESS) {
Log.w(TAG,"onCharacteristicWrite [" + getDataHex(characteristic.getValue()) + "]");
// gatt.disconnect();
if(mBluetoothGatt!=null)
mBluetoothGatt.close();
// gatt.close();
// mBluetoothGatt=null;
}
else if(status ==133)
{
gatt.close();
try
{
Thread.sleep(2000);
}
catch(Exception e)
{
}
readCharacteristic();
}
else{
//gatt.disconnect();
gatt.close();
}
}
@Override
public void onCharacteristicRead(BluetoothGatt gatt,
BluetoothGattCharacteristic characteristic,
int status) {
Log.w(TAG,"onCharacteristicRead [" + status + "]");
if (status == BluetoothGatt.GATT_SUCCESS) {
mValue = characteristic.getValue();
// Perform write operations
gatt.writeCharacteristic(bgc);
}
else if(status ==133)
{
gatt.close();
try
{
Thread.sleep(2000);
}
catch(Exception e)
{
}
readCharacteristic();
}
else {
// gatt.disconnect();
gatt.close();
}
}
}
此代码在运行kitkat及以下版本的设备上运行得非常好。但在运行棒棒糖的设备上,这段代码在第一次运行时效果良好。但从下一个实例来看,不管我是断开连接还是关闭连接并重试,它都不起作用。它一直在onconnectionstatechange方法中给我一个257的状态代码。据我所知,蓝牙gatt方法对kitkat和棒棒糖设备都是一样的。
令我惊讶的是,当我使用旧的ble api即startedscan(用于eg-
mBluetoothAdapter.startLeScan(mLeScanCallback);
)时,这段代码在棒棒糖设备上运行良好。这个问题只在我使用新的ble api时出现,即bluetoothlescanner(scanner.startScan(filters, settings, new scancallback());
)。对于使用旧的ble api的棒棒糖设备,扫描速度非常慢,因此我不能使用它。我就是不明白怎么解决这个问题。有没有人面对同样的问题,找到了解决办法?任何帮助都将不胜感激。 最佳答案
我在这里会改变很多事情。为要从特征中读取的数据创建类变量,例如私有字符串心率;
1)不需要readCharacteristic()方法。相反,在onconnectionstatechange中,一旦设备连接正确,就调用mbluetothgatt.discoverservices()。然后在onServicesDiscovered()方法中调用gatt.getServices()。然后使用foreach循环并遍历返回的服务,并比较服务的uuid,直到找到您关心的那个。然后,如果heartrate==null,则调用service.getCharacteristic(heartrateUuid),然后读取特征。在onCharacteristicRead()中,检查uuid是否等于心率特征。如果是,则将特征值赋给心率变量。如果您感兴趣,我可以键入方法或提供伪代码。
2)我不会调用gatt.connect(),然后调用gatt.discoverservices()。gatt.connect()将在看到来自当前设备的播发数据包时立即重新连接到该设备。我将调用gatt.connect(),然后在onconnectedstatechange()方法中调用gatt.discoverservices()。
3)在onconnectedstatechange方法中,不要使用gatt变量。改用MBluetothGatt。mbluetothgatt.disconnect()断开与当前连接设备的连接。mbluetothgatt.close()终止gatt实例。在调用mbluetothgatt.close()之后,不能调用mbluetothgatt.connect()。这可能不需要,但如果设备已连接,我将调用mbluetothgatt.disconnect(),然后调用mbluetothgatt.close()。
4)您也可以将特征读数连在一起。在onCharacteristicRead()中,获取心率值后,可以立即调用characteristic.getService().getCharacteristic(uuidTemperature),然后读取该特征。它将再次调用onCharacteristicRead方法。
如果你想让我澄清什么,请告诉我;我在用蹩脚的Surface Pro 3键盘打字。:)