问题：

.discoverServices()调用之后，却永远不回调onServicesDiscovered(BluetoothGatt gatt, int status)

基本代码如下：

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());

            } else if (newState == BluetoothProfile.STATE_DISCONNECTED) {

                intentAction = ACTION_GATT_DISCONNECTED;

                mConnectionState = STATE_DISCONNECTED;

                Log.i(TAG, "Disconnected from GATT server.");

                broadcastUpdate(intentAction);

            }

        }

原因：

android 提示newState == BluetoothProfile.STATE_CONNECTED

而实际上并不一定连接上了（连接成功是假象），尤其是连接一个不存在的设备。

参考资料：

http://stackoverflow.com/questions/25848764/onservicesdiscoveredbluetoothgatt-gatt-int-status-is-never-called