We now have a "connecting" state in the ControlActivity.

sample_app/src/main/java/uk/co/alt236/btlescan/services/BluetoothLeService.java

@@ -39,22 +39,20 @@ import java.util.List;
  */
 public class BluetoothLeService extends Service {
     public final static String ACTION_GATT_CONNECTED = BluetoothLeService.class.getName() + ".ACTION_GATT_CONNECTED";
+    public final static String ACTION_GATT_CONNECTING = BluetoothLeService.class.getName() + ".ACTION_GATT_CONNECTING";
     public final static String ACTION_GATT_DISCONNECTED = BluetoothLeService.class.getName() + ".ACTION_GATT_DISCONNECTED";
     public final static String ACTION_GATT_SERVICES_DISCOVERED = BluetoothLeService.class.getName() + ".ACTION_GATT_SERVICES_DISCOVERED";
     public final static String ACTION_DATA_AVAILABLE = BluetoothLeService.class.getName() + ".ACTION_DATA_AVAILABLE";
     public final static String EXTRA_DATA_RAW = BluetoothLeService.class.getName() + ".EXTRA_DATA_RAW";
     public final static String EXTRA_UUID_CHAR = BluetoothLeService.class.getName() + ".EXTRA_UUID_CHAR";
     private final static String TAG = BluetoothLeService.class.getSimpleName();
-
-    private static final int STATE_DISCONNECTED = 0;
-    private static final int STATE_CONNECTING = 1;
-    private static final int STATE_CONNECTED = 2;
     private final IBinder mBinder = new LocalBinder();
     private BluetoothManager mBluetoothManager;
     private BluetoothAdapter mBluetoothAdapter;
     private String mBluetoothDeviceAddress;
     private BluetoothGatt mBluetoothGatt;
-    private int mConnectionState = STATE_DISCONNECTED;
+    private State mConnectionState = State.DISCONNECTED;
+
     // Implements callback methods for GATT events that the app cares about.  For example,
     // connection change and services discovered.
     private final BluetoothGattCallback mGattCallback = new BluetoothGattCallback() {
@@ -64,28 +62,35 @@ public class BluetoothLeService extends Service {
         }
 
         @Override
-        public void onCharacteristicRead(final BluetoothGatt gatt, final BluetoothGattCharacteristic characteristic, final int status) {
+        public void onCharacteristicRead(final BluetoothGatt gatt,
+                                         final BluetoothGattCharacteristic characteristic,
+                                         final int status) {
+
             if (status == BluetoothGatt.GATT_SUCCESS) {
                 broadcastUpdate(ACTION_DATA_AVAILABLE, characteristic);
             }
         }
 
         @Override
-        public void onConnectionStateChange(final BluetoothGatt gatt, final int status, final int newState) {
+        public void onConnectionStateChange(final BluetoothGatt gatt,
-            final String intentAction;
+                                            final int status,
+                                            final int newState) {
+
+            Log.d(TAG, "onConnectionStateChange: status=" + status + ", newState=" + newState);
+
             if (newState == BluetoothProfile.STATE_CONNECTED) {
-                intentAction = ACTION_GATT_CONNECTED;
+                setConnectionState(State.CONNECTED, true);
-                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;
+                // Make sure we tidy up. On certain devices reusing a Gatt after a disconnection
-                mConnectionState = STATE_DISCONNECTED;
+                // can cause problems.
+                disconnect();
+
+                setConnectionState(State.DISCONNECTED, true);
                 Log.i(TAG, "Disconnected from GATT server.");
-                broadcastUpdate(intentAction);
             }
         }
 
@@ -139,37 +144,73 @@ public class BluetoothLeService extends Service {
      * callback.
      */
     public boolean connect(final String address) {
+
+        final boolean retVal;
         if (mBluetoothAdapter == null || address == null) {
             Log.w(TAG, "BluetoothAdapter not initialized or unspecified address.");
-            return false;
+            retVal = false;
-        }
 
-        // Previously connected device.  Try to reconnect.
+            // Previously connected device.  Try to reconnect.
-        if (mBluetoothDeviceAddress != null
+        } else if (mBluetoothDeviceAddress != null
                 && address.equals(mBluetoothDeviceAddress)
                 && mBluetoothGatt != null) {
 
             Log.d(TAG, "Trying to use an existing mBluetoothGatt for connection.");
             if (mBluetoothGatt.connect()) {
-                mConnectionState = STATE_CONNECTING;
+                Log.d(TAG, "Connection attempt OK.");
-                return true;
+                setConnectionState(State.CONNECTING, true);
+                retVal = true;
             } else {
-                return false;
+                Log.w(TAG, "Connection attempt failed.");
+                setConnectionState(State.DISCONNECTED, true);
+                retVal = false;
+            }
+        } else {
+
+            final BluetoothDevice device = mBluetoothAdapter.getRemoteDevice(address);
+            if (device == null) {
+                Log.w(TAG, "Device not found.  Unable to connect.");
+                retVal = false;
+            } else {
+                // We want to directly connect to the device, so we are setting the autoConnect
+                // parameter to false.
+
+                Log.d(TAG, "Trying to create a new connection.");
+                mBluetoothGatt = device.connectGatt(this, false, mGattCallback);
+                mBluetoothDeviceAddress = address;
+                setConnectionState(State.CONNECTING, true);
+                retVal = true;
             }
         }
 
-        final BluetoothDevice device = mBluetoothAdapter.getRemoteDevice(address);
+        return retVal;
-        if (device == null) {
+    }
-            Log.w(TAG, "Device not found.  Unable to connect.");
+
-            return false;
+    private synchronized void setConnectionState(final State newState, final boolean broadCast) {
+        Log.i(TAG, "Setting internal state to " + newState);
+        mConnectionState = newState;
+
+        final String broadcastAction;
+
+        switch (newState) {
+            case CONNECTED:
+                broadcastAction = ACTION_GATT_CONNECTED;
+                break;
+            case CONNECTING:
+                broadcastAction = ACTION_GATT_CONNECTING;
+                break;
+            case DISCONNECTED:
+                broadcastAction = ACTION_GATT_DISCONNECTED;
+                break;
+            default:
+                throw new IllegalArgumentException("Unknown state: " + newState);
         }
-        // We want to directly connect to the device, so we are setting the autoConnect
+
-        // parameter to false.
+        if (broadCast) {
-        mBluetoothGatt = device.connectGatt(this, false, mGattCallback);
+            Log.i(TAG, "Broadcasting " + broadcastAction);
-        Log.d(TAG, "Trying to create a new connection.");
+            broadcastUpdate(broadcastAction);
-        mBluetoothDeviceAddress = address;
+        }
-        mConnectionState = STATE_CONNECTING;
+
-        return true;
     }
 
     /**
@@ -184,6 +225,9 @@ public class BluetoothLeService extends Service {
             return;
         }
         mBluetoothGatt.disconnect();
+
+        // Reusing a Gatt after disconnecting can cause problems
+        mBluetoothGatt = null;
     }
 
     /**
@@ -271,4 +315,10 @@ public class BluetoothLeService extends Service {
             return BluetoothLeService.this;
         }
     }
+
+    private enum State {
+        DISCONNECTED,
+        CONNECTING,
+        CONNECTED
+    }
 }

sample_app/src/main/java/uk/co/alt236/btlescan/ui/control/DeviceControlActivity.java

@@ -121,7 +121,8 @@ public class DeviceControlActivity extends AppCompatActivity {
         }
     };
     private BluetoothLeDevice mDevice;
-    private boolean mConnected = false;
+    private State mCurrentState = State.DISCONNECTED;
+
     private String mExportString;
     // Handles various events fired by the Service.
     // ACTION_GATT_CONNECTED: connected to a GATT server.
@@ -134,14 +135,16 @@ public class DeviceControlActivity extends AppCompatActivity {
         public void onReceive(final Context context, final Intent intent) {
             final String action = intent.getAction();
             if (BluetoothLeService.ACTION_GATT_CONNECTED.equals(action)) {
-                mConnected = true;
+                updateConnectionState(State.CONNECTED);
-                updateConnectionState(R.string.connected);
                 invalidateOptionsMenu();
             } else if (BluetoothLeService.ACTION_GATT_DISCONNECTED.equals(action)) {
-                mConnected = false;
-                updateConnectionState(R.string.disconnected);
-                invalidateOptionsMenu();
                 clearUI();
+                updateConnectionState(State.DISCONNECTED);
+                invalidateOptionsMenu();
+            } else if (BluetoothLeService.ACTION_GATT_CONNECTING.equals(action)) {
+                clearUI();
+                updateConnectionState(State.CONNECTING);
+                invalidateOptionsMenu();
             } else if (BluetoothLeService.ACTION_GATT_SERVICES_DISCOVERED.equals(action)) {
                 // Show all the supported services and characteristics on the user interface.
                 displayGattServices(mBluetoothLeService.getSupportedGattServices());
@@ -159,6 +162,7 @@ public class DeviceControlActivity extends AppCompatActivity {
     };
 
     private void clearUI() {
+        mExportString = null;
         mGattServicesList.setAdapter((SimpleExpandableListAdapter) null);
         mGattUUID.setText(R.string.no_data);
         mGattUUIDDesc.setText(R.string.no_data);
@@ -206,12 +210,26 @@ public class DeviceControlActivity extends AppCompatActivity {
     @Override
     public boolean onCreateOptionsMenu(final Menu menu) {
         getMenuInflater().inflate(R.menu.gatt_services, menu);
-        if (mConnected) {
+
-            menu.findItem(R.id.menu_connect).setVisible(false);
+        switch (mCurrentState) {
-            menu.findItem(R.id.menu_disconnect).setVisible(true);
+
-        } else {
+            case DISCONNECTED:
-            menu.findItem(R.id.menu_connect).setVisible(true);
+                menu.findItem(R.id.menu_connect).setVisible(true);
-            menu.findItem(R.id.menu_disconnect).setVisible(false);
+                menu.findItem(R.id.menu_disconnect).setVisible(false);
+                menu.findItem(R.id.menu_refresh).setActionView(null);
+                break;
+            case CONNECTING:
+                menu.findItem(R.id.menu_connect).setVisible(false);
+                menu.findItem(R.id.menu_disconnect).setVisible(false);
+                menu.findItem(R.id.menu_refresh).setActionView(R.layout.actionbar_progress_indeterminate);
+                break;
+            case CONNECTED:
+                menu.findItem(R.id.menu_connect).setVisible(false);
+                menu.findItem(R.id.menu_disconnect).setVisible(true);
+                menu.findItem(R.id.menu_refresh).setActionView(null);
+                break;
+            default:
+                throw new IllegalStateException("Don't know how to handle: " + mCurrentState);
         }
 
         if (mExportString == null) {
@@ -278,25 +296,35 @@ public class DeviceControlActivity extends AppCompatActivity {
         }
     }
 
-    private void updateConnectionState(final int resourceId) {
+    private void updateConnectionState(final State state) {
+        mCurrentState = state;
+
         runOnUiThread(new Runnable() {
             @Override
             public void run() {
                 final int colourId;
+                final int resId;
 
-                switch (resourceId) {
+                switch (state) {
-                    case R.string.connected:
+                    case CONNECTED:
                         colourId = android.R.color.holo_green_dark;
+                        resId = R.string.connected;
                         break;
-                    case R.string.disconnected:
+                    case DISCONNECTED:
                         colourId = android.R.color.holo_red_dark;
+                        resId = R.string.disconnected;
+                        break;
+                    case CONNECTING:
+                        colourId = android.R.color.black;
+                        resId = R.string.connecting;
                         break;
                     default:
                         colourId = android.R.color.black;
+                        resId = 0;
                         break;
                 }
 
-                mConnectionState.setText(resourceId);
+                mConnectionState.setText(resId);
                 mConnectionState.setTextColor(ContextCompat.getColor(DeviceControlActivity.this, colourId));
             }
         });
@@ -308,6 +336,7 @@ public class DeviceControlActivity extends AppCompatActivity {
         intentFilter.addAction(BluetoothLeService.ACTION_GATT_DISCONNECTED);
         intentFilter.addAction(BluetoothLeService.ACTION_GATT_SERVICES_DISCOVERED);
         intentFilter.addAction(BluetoothLeService.ACTION_DATA_AVAILABLE);
+        intentFilter.addAction(BluetoothLeService.ACTION_GATT_CONNECTING);
         return intentFilter;
     }
 
@@ -324,4 +353,10 @@ public class DeviceControlActivity extends AppCompatActivity {
         intent.putExtra(DeviceControlActivity.EXTRA_DEVICE, device);
         return intent;
     }
+
+    private enum State {
+        DISCONNECTED,
+        CONNECTING,
+        CONNECTED
+    }
 }

sample_app/src/main/res/values/strings.xml

@@ -5,6 +5,7 @@
     <string name="app_name">Bluetooth LE Scanner</string>
     <string name="connected">Connected</string>
     <string name="disconnected">Disconnected</string>
+    <string name="connecting">Connecting</string>
     <string name="invalid_device_data">Invalid Device Data!</string>
     <string name="no_data">No data</string>
     <string name="not_supported">Not supported</string>