上周我遇到了一个奇怪的问题，很快就会让我发疯，Stackoverflow是我最后的希望。 我只是写了一个与BLE设备通信的代码。起初我只是在写一个特征值。
public void writeEnableCredentials(String keysFn) {
if ( sGattCharList != null) {
Log.i("Callback WEC Method: ", "Start!!!/n" );
String val = keysFn.substring(0, 2);
String val2 = keysFn.substring(2, 4);
int val_1 = Integer.parseInt(val);
int val_2 = Integer.parseInt(val2);
byte[] rk_byte_Value = new byte[1];
final byte[] rk_byte_Value_2 = new byte[1];
rk_byte_Value[0] = (byte)(val_1 & 0xFF);
rk_byte_Value_2[0] = (byte)(val_2 & 0xFF);
sGattCharList.get(1).setValue(rk_byte_Value);
boolean ok = sBluetoothGatt.writeCharacteristic(sGattCharList.get(1));
Log.i("Callback WEC Method: ", "1 Verified = " + ok);
if(ok) {
final Handler handler = new Handler();
handler.postDelayed(new Runnable() {
@Override
public void run() {
sGattCharList.get(2).setValue(rk_byte_Value_2);
boolean ok = sBluetoothGatt.writeCharacteristic(sGattCharList.get(2));
Log.i("Callback WEC Method: ", "2 Verified = " + ok);
}
}, 100);
}
} else {
Toast.makeText(activity, "Wait for services", Toast.LENGTH_SHORT).show();
}
Log.i("Callback WEC Method: ", "Stop!!!/n" );
}
BluetoothGattCallback方法如下：
private final BluetoothGattCallback sGattCallback = new BluetoothGattCallback() {
@Override
public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
if (newState == BluetoothProfile.STATE_CONNECTED) {
Log.i("CallbackGatt","Connecting with " + sDevice.getsMac());
sBluetoothGatt.discoverServices();
}
else if (newState == BluetoothProfile.STATE_DISCONNECTED) {
sBluetoothGatt.close();
Log.i("CallbackGatt", "Disconnected from GATT server.");
}
}
@Override
public void onServicesDiscovered(BluetoothGatt gatt, int status) {
services_List = gatt.getServices();
sGattCharList = services_List.get(3).getCharacteristics();
Log.i("CallbackGatt","Characteristic List Found: " + sGattCharList);
}
@Override
public void onCharacteristicWrite(BluetoothGatt gatt,
BluetoothGattCharacteristic characteristic, int status) {
if(status == BluetoothGatt.GATT_SUCCESS) {
byte[] bytes = characteristic.getValue();
System.out.println("ON Characteristic WRITE Callback: " + characteristic.getUuid()+" value: "+bytes);
}
}
};
问题：此代码在API＆gt; 22上完美运行。 API上的但＆lt; = 22 BluetoothGattCallback无法正常工作，有时收到回调但在再次运行相同的构建后我没有收到回调和特征没写。
调试日志在5.1.1上运行构建
*Trying to write 1st time*
07-04 00:29:28.370 19270-19270/com.example.xxx.xxxx/Callback WEC Method:: Start!!!/n
07-04 00:29:28.371 19270-19270/com.example.xxx.xxxx I/Callback WEC Method:: 1 Verified = true
07-04 00:29:28.372 19270-19270/com.example.xxx.xxxx I/Callback WEC Method:: Stop!!!/n
07-04 00:29:28.472 9115-9185/? E/bt-btif: already has a pending command!!
07-04 00:29:28.472 9115-9185/? E/bt-att: GATTC_Write GATT_BUSY conn_id = 6
07-04 00:29:28.474 19270-19270/com.example.xxx.xxxx I/Callback WEC Method:: 2 Verified = true
*Trying to write 2nd time*
07-04 00:29:33.371 19270-19270/com.example.xxx.xxxx I/Callback WEC Method:: Start!!!/n
07-04 00:29:33.371 9115-9185/? E/bt-att: GATTC_Write GATT_BUSY conn_id = 6
07-04 00:29:33.371 9115-9185/? E/GKI_LINUX: GKI_exception(): Task State Table
07-04 00:29:33.371 9115-9185/? E/GKI_LINUX: TASK ID [0] task name [BTU] state [1]
07-04 00:29:33.371 9115-9185/? E/GKI_LINUX: TASK ID [1] task name [BTIF] state [1]
07-04 00:29:33.371 9115-9185/? E/GKI_LINUX: TASK ID [2] task name [A2DP-MEDIA] state [1]
07-04 00:29:33.371 9115-9185/? E/GKI_LINUX: GKI_exception 65532 Freeing Linked Buf
07-04 00:29:33.372 9115-9185/? E/GKI_LINUX: ********************************************************************
07-04 00:29:33.372 9115-9185/? E/GKI_LINUX: * GKI_exception(): 65532 Freeing Linked Buf
07-04 00:29:33.372 9115-9185/? E/GKI_LINUX: ********************************************************************
07-04 00:29:33.372 19270-19270/com.example.xxx.xxxx I/Callback WEC Method:: 1 Verified = true
07-04 00:29:33.373 19270-19270/com.example.xxx.xxxx I/Callback WEC Method:: Stop!!!/n
07-04 00:29:33.474 9115-9185/? E/bt-att: GATTC_Write GATT_BUSY conn_id = 6
07-04 00:29:33.474 19270-19270/com.example.xxx.xxxx I/Callback WEC Method:: 2 Verified = true
07-04 00:29:33.474 9115-9185/? E/GKI_LINUX: GKI_exception(): Task State Table
07-04 00:29:33.474 9115-9185/? E/GKI_LINUX: TASK ID [0] task name [BTU] state [1]
07-04 00:29:33.474 9115-9185/? E/GKI_LINUX: TASK ID [1] task name [BTIF] state [1]
07-04 00:29:33.474 9115-9185/? E/GKI_LINUX: TASK ID [2] task name [A2DP-MEDIA] state [1]
07-04 00:29:33.474 9115-9185/? E/GKI_LINUX: GKI_exception 65532 Freeing Linked Buf
07-04 00:29:33.474 9115-9185/? E/GKI_LINUX: ********************************************************************
07-04 00:29:33.474 9115-9185/? E/GKI_LINUX: * GKI_exception(): 65532 Freeing Linked Buf
07-04 00:29:33.474 9115-9185/? E/GKI_LINUX: ********************************************************************
07-04 00:29:33.562 339-339/? I/Gobi: vendor/qcom/proprietary/RIDL/RIDLClient/RIDLSQL.cpp:1920: GetTransState() EBADF
07-04 00:29:33.562 339-339/? I/Gobi: vendor/qcom/proprietary/RIDL/RIDLClient/MainCore.cpp:1346: Failed to get TransState, rc
07-04 00:29:33.562 339-339/? I/Gobi: vendor/qcom/proprietary/RIDL/RIDLClient/RIDLSQL.cpp:1920: GetTransState() EBADF
kill app =＆gt; clear cache =＆gt; start app =＆gt; make connection =＆gt;尝试写=＆gt;杀死app
完成这个过程4次后我终于得到了回调：D
07-04 00:34:39.144 26148-26148/com.example.xxx.xxxx I/Callback WEC Method:: Start!!!/n
07-04 00:34:39.147 26148-26148/com.example.xxx.xxxx I/Callback WEC Method:: 1 Verified = true
07-04 00:34:39.147 26148-26148/com.example.xxx.xxxx I/Callback WEC Method:: Stop!!!/n
07-04 00:34:39.233 26148-26166/com.example.xxx.xxxx I/System.out: ON Characteristic WRITE Callback: 0000fff2-0000-1000-8000-00805f9b34fb
07-04 00:34:39.247 26148-26148/com.example.xxx.xxxx I/Callback WEC Method:: 2 Verified = true
07-04 00:34:39.331 26148-26165/com.example.xxx.xxxx I/System.out: ON Characteristic WRITE Callback: 0000fff3-0000-1000-8000-00805f9b34fb
如果你们需要任何其他细节，请询问。另请告诉我是什么： E / GKI_LINUX：GKI_exception ，谢谢。
答案 0 :(得分：0)
在发出新操作之前，您需要等待写回调。只需等待100毫秒就无法保证正常工作，因为它可能需要更长的时间才能获得回调。