Try to run all ble commands on the main thread

android_app/app/src/main/java/com/health/openscale/core/bluetooth/BluetoothCommunication.java

@@ -80,7 +80,6 @@ public abstract class BluetoothCommunication {
     private Queue<GattObjectValue<BluetoothGattDescriptor>> descriptorRequestQueue;
     private Queue<GattObjectValue<BluetoothGattCharacteristic>> characteristicRequestQueue;
     private boolean openRequest;
-    private final Object lock = new Object();
 
     public BluetoothCommunication(Context context)
     {
@@ -240,11 +239,9 @@ public abstract class BluetoothCommunication {
      * @param btMachineState the machine state that should be set.
      */
     protected void setBtMachineState(BT_MACHINE_STATE btMachineState) {
-        synchronized (lock) {
         this.btMachineState = btMachineState;
         handleRequests();
     }
-    }
 
     /**
      * Write a byte array to a Bluetooth device.
@@ -254,14 +251,12 @@ public abstract class BluetoothCommunication {
      * @param bytes the bytes that should be write
      */
     protected void writeBytes(UUID service, UUID characteristic, byte[] bytes) {
-        synchronized (lock) {
          characteristicRequestQueue.add(
                  new GattObjectValue<>(
                          bluetoothGatt.getService(service).getCharacteristic(characteristic),
                          bytes));
          handleRequests();
     }
-    }
 
     /**
      * Read bytes from a Bluetooth device.
@@ -301,14 +296,12 @@ public abstract class BluetoothCommunication {
                     bluetoothGatt.getService(service).getCharacteristic(characteristic);
             bluetoothGatt.setCharacteristicNotification(gattCharacteristic, true);
 
-            synchronized (lock) {
             descriptorRequestQueue.add(
                     new GattObjectValue<>(
                             gattCharacteristic.getDescriptor(descriptor),
                             BluetoothGattDescriptor.ENABLE_INDICATION_VALUE));
             handleRequests();
         }
-        }
         catch (Exception e) {
             Timber.e(e);
         }
@@ -328,14 +321,12 @@ public abstract class BluetoothCommunication {
                     bluetoothGatt.getService(service).getCharacteristic(characteristic);
             bluetoothGatt.setCharacteristicNotification(gattCharacteristic, true);
 
-            synchronized (lock) {
             descriptorRequestQueue.add(
                     new GattObjectValue<>(
                             gattCharacteristic.getDescriptor(descriptor),
                             BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE));
             handleRequests();
         }
-        }
         catch (Exception e) {
             Timber.e(e);
         }
@@ -354,14 +345,12 @@ public abstract class BluetoothCommunication {
                 bluetoothGatt.getService(service).getCharacteristic(characteristic);
         bluetoothGatt.setCharacteristicNotification(gattCharacteristic, false);
 
-        synchronized (lock) {
         descriptorRequestQueue.add(
                 new GattObjectValue<>(
                         gattCharacteristic.getDescriptor(descriptor),
                         BluetoothGattDescriptor.DISABLE_NOTIFICATION_VALUE));
         handleRequests();
     }
-    }
 
     /**
      * Convert a byte array to hex for debugging purpose
@@ -415,6 +404,8 @@ public abstract class BluetoothCommunication {
      * @param hwAddress the Bluetooth address to connect to
      */
     public void connect(String hwAddress) {
+        disconnect(false);
+
         logBluetoothStatus();
 
         // Some good tips to improve BLE connections:
@@ -481,6 +472,7 @@ public abstract class BluetoothCommunication {
                 if (!device.getAddress().equals(hwAddress)) {
                     return;
                 }
+                // Stop scan and connect to the device on the main thread
                 handler.post(new Runnable() {
                     @Override
                     public void run() {
@@ -496,15 +488,14 @@ public abstract class BluetoothCommunication {
         Timber.d("Starting LE scan for device [%s]", hwAddress);
         btAdapter.startLeScan(leScanCallback);
 
+        // Stop scan and try to connect to the device directly if the device isn't found in time
         handler.postAtTime(new Runnable() {
             @Override
             public void run() {
                 Timber.d("Device not found in LE scan, connecting directly");
-                synchronized (lock) {
                 stopLeScan();
                 connectGatt(hwAddress);
             }
-            }
         }, leScanCallback, SystemClock.uptimeMillis() + LE_SCAN_TIMEOUT_MS);
     }
 
@@ -521,7 +512,6 @@ public abstract class BluetoothCommunication {
      * Disconnect from a Bluetooth device
      */
     public void disconnect(boolean doCleanup) {
-        synchronized (lock) {
         stopLeScan();
 
         if (bluetoothGatt == null) {
@@ -530,9 +520,6 @@ public abstract class BluetoothCommunication {
 
         Timber.i("Disconnecting%s", doCleanup ? " (with cleanup)" : "");
 
-            handler.removeCallbacksAndMessages(null);
-            callbackBtHandler = null;
-
         if (doCleanup) {
             if (btMachineState != BT_MACHINE_STATE.BT_CLEANUP_STATE) {
                 setBtMachineState(BT_MACHINE_STATE.BT_CLEANUP_STATE);
@@ -541,13 +528,12 @@ public abstract class BluetoothCommunication {
             handler.post(new Runnable() {
                 @Override
                 public void run() {
-                        synchronized (lock) {
                     if (openRequest) {
                         handler.postDelayed(this, 10);
                     } else {
                         bluetoothGatt.close();
                         bluetoothGatt = null;
-                            }
+                        handler.removeCallbacksAndMessages(null);
                     }
                 }
             });
@@ -556,7 +542,9 @@ public abstract class BluetoothCommunication {
             bluetoothGatt.close();
             bluetoothGatt = null;
         }
-        }
+
+        handler.removeCallbacksAndMessages(null);
+        callbackBtHandler = null;
     }
 
     /**
@@ -586,7 +574,6 @@ public abstract class BluetoothCommunication {
     }
 
     private void handleRequests() {
-        synchronized (lock) {
         // check for pending request
         if (openRequest) {
             Timber.d("Request pending (queue %d %d)",
@@ -615,8 +602,9 @@ public abstract class BluetoothCommunication {
         if (characteristic != null) {
             characteristic.gattObject.setValue(characteristic.value);
 
-                Timber.d("Write characteristic %s: %s (queue: %d %d)",
+            Timber.d("Write characteristic %s: %s (type: %d; queue: %d %d)",
                     characteristic.gattObject.getUuid(), byteInHex(characteristic.gattObject.getValue()),
+                    characteristic.gattObject.getWriteType(),
                     descriptorRequestQueue.size(), characteristicRequestQueue.size());
             if (!bluetoothGatt.writeCharacteristic(characteristic.gattObject)) {
                 Timber.e("Failed to initiate write of characteristic %s",
@@ -629,7 +617,6 @@ public abstract class BluetoothCommunication {
         // After every command was executed, continue with the next step
         nextMachineStateStep();
     }
-    }
 
     /**
      * Custom Gatt callback class to set up a Bluetooth state machine.
@@ -640,9 +627,10 @@ public abstract class BluetoothCommunication {
             Timber.d("onConnectionStateChange: status=%d, newState=%d", status, newState);
 
             if (newState == BluetoothProfile.STATE_CONNECTED) {
-                synchronized (lock) {
+                handler.post(new Runnable() {
+                    @Override
+                    public void run() {
                         stopLeScan();
-                }
 
                         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
                             gatt.readPhy();
@@ -650,25 +638,32 @@ public abstract class BluetoothCommunication {
 
                         connectionEstablished = true;
                         setBtStatus(BT_STATUS_CODE.BT_CONNECTION_ESTABLISHED);
+                    }
+                });
 
-                try {
+                // Wait a short while after connecting before scanning for services
-                    Thread.sleep(1000);
+                handler.postDelayed(new Runnable() {
-                }
+                    @Override
-                catch (Exception e) {
+                    public void run() {
-                    // Empty
-                }
                         if (!gatt.discoverServices()) {
                             Timber.e("Could not start service discovery");
                             setBtStatus(BT_STATUS_CODE.BT_CONNECTION_LOST);
                             disconnect(false);
                         }
                     }
+                }, 1000);
+            }
             else if (newState == BluetoothProfile.STATE_DISCONNECTED) {
+                handler.post(new Runnable() {
+                    @Override
+                    public void run() {
                         setBtStatus(connectionEstablished
                                 ? BT_STATUS_CODE.BT_CONNECTION_LOST
                                 : BT_STATUS_CODE.BT_NO_DEVICE_FOUND);
                         disconnect(false);
                     }
+                });
+            }
         }
 
         @Override
@@ -677,12 +672,22 @@ public abstract class BluetoothCommunication {
                     status, gatt.getServices().size());
 
             if (gatt.getServices().isEmpty()) {
+                handler.post(new Runnable() {
+                    @Override
+                    public void run() {
                         setBtStatus(BT_STATUS_CODE.BT_UNEXPECTED_ERROR, "No services found");
                         disconnect(false);
+                    }
+                });
                 return;
             }
 
-            synchronized (lock) {
+            // Sleeping a while after discovering services fixes connection problems.
+            // See https://github.com/NordicSemiconductor/Android-DFU-Library/issues/10
+            // for some technical background.
+            handler.postDelayed(new Runnable() {
+                @Override
+                public void run() {
                     cmdStepNr = 0;
                     initStepNr = 0;
                     cleanupStepNr = 0;
@@ -691,21 +696,12 @@ public abstract class BluetoothCommunication {
                     characteristicRequestQueue = new LinkedList<>();
                     descriptorRequestQueue = new LinkedList<>();
                     openRequest = false;
-            }
-
-            try {
-                // Sleeping a while after discovering services fixes connection problems.
-                // See https://github.com/NordicSemiconductor/Android-DFU-Library/issues/10
-                // for some technical background.
-                Thread.sleep(1000);
-            }
-            catch (Exception e) {
-                // Empty
-            }
 
                     // Start the state machine
                     setBtMachineState(BT_MACHINE_STATE.BT_INIT_STATE);
                 }
+            }, 1000);
+        }
 
         @Override
         public void onPhyRead(BluetoothGatt gatt, int txPhy, int rxPhy, int status) {
@@ -723,11 +719,9 @@ public abstract class BluetoothCommunication {
             handler.postDelayed(new Runnable() {
                 @Override
                 public void run() {
-                    synchronized (lock) {
                     openRequest = false;
                     handleRequests();
                 }
-                }
             }, 60);
         }
 
@@ -746,27 +740,33 @@ public abstract class BluetoothCommunication {
         }
 
         @Override
-        public void onCharacteristicRead(BluetoothGatt gatt,
+        public void onCharacteristicRead(final BluetoothGatt gatt,
-                                         BluetoothGattCharacteristic characteristic,
+                                         final BluetoothGattCharacteristic characteristic,
-                                         int status) {
+                                         final int status) {
             Timber.d("onCharacteristicRead %s (status=%d): %s",
                     characteristic.getUuid(), status, byteInHex(characteristic.getValue()));
 
-            synchronized (lock) {
+            handler.post(new Runnable() {
+                @Override
+                public void run() {
                     onBluetoothDataRead(gatt, characteristic, status);
-                postDelayedHandleRequests();
                 }
+            });
+            postDelayedHandleRequests();
         }
 
         @Override
-        public void onCharacteristicChanged(BluetoothGatt gatt,
+        public void onCharacteristicChanged(final BluetoothGatt gatt,
-                                            BluetoothGattCharacteristic characteristic) {
+                                            final BluetoothGattCharacteristic characteristic) {
             Timber.d("onCharacteristicChanged %s: %s",
                     characteristic.getUuid(), byteInHex(characteristic.getValue()));
 
-            synchronized (lock) {
+            handler.post(new Runnable() {
+                @Override
+                public void run() {
                     onBluetoothDataChange(gatt, characteristic);
                 }
+            });
         }
 
         @Override