Continue scanning/connecting after user enables bluetooth

android_app/app/src/main/java/com/health/openscale/gui/MainActivity.java

@@ -18,6 +18,7 @@ package com.health.openscale.gui;
 
 import android.annotation.SuppressLint;
 import android.app.AlertDialog;
+import android.bluetooth.BluetoothAdapter;
 import android.bluetooth.BluetoothManager;
 import android.content.ActivityNotFoundException;
 import android.content.DialogInterface;
@@ -80,6 +81,7 @@ public class MainActivity extends BaseAppCompatActivity
 
     private static final int IMPORT_DATA_REQUEST = 100;
     private static final int EXPORT_DATA_REQUEST = 101;
+    private static final int ENABLE_BLUETOOTH_REQUEST = 102;
 
     private DrawerLayout drawerLayout;
     private Toolbar toolbar;
@@ -461,6 +463,13 @@ public class MainActivity extends BaseAppCompatActivity
             return;
         }
 
+        BluetoothManager bluetoothManager = (BluetoothManager) getSystemService(BLUETOOTH_SERVICE);
+        if (!bluetoothManager.getAdapter().isEnabled()) {
+            Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
+            startActivityForResult(enableBtIntent, ENABLE_BLUETOOTH_REQUEST);
+            return;
+        }
+
         Toast.makeText(getApplicationContext(), getResources().getString(R.string.info_bluetooth_try_connection) + " " + deviceName, Toast.LENGTH_SHORT).show();
         setBluetoothStatusIcon(R.drawable.ic_bluetooth_searching);
 
@@ -664,6 +673,16 @@ public class MainActivity extends BaseAppCompatActivity
     public void onActivityResult(int requestCode, int resultCode, Intent data) {
         super.onActivityResult(requestCode, resultCode, data);
 
+        if (requestCode == ENABLE_BLUETOOTH_REQUEST) {
+            if (resultCode == RESULT_OK) {
+                invokeConnectToBluetoothDevice();
+            }
+            else {
+                Toast.makeText(this, "Bluetooth " + getResources().getString(R.string.info_is_not_enable), Toast.LENGTH_SHORT).show();
+            }
+            return;
+        }
+
         if (resultCode != RESULT_OK || data == null) {
             return;
         }

android_app/app/src/main/java/com/health/openscale/gui/preferences/BluetoothPreferences.java

@@ -15,6 +15,8 @@
 */
 package com.health.openscale.gui.preferences;
 
+import android.app.Activity;
+import android.app.Fragment;
 import android.bluetooth.BluetoothAdapter;
 import android.bluetooth.BluetoothDevice;
 import android.content.BroadcastReceiver;
@@ -207,10 +209,11 @@ public class BluetoothPreferences extends PreferenceFragment {
             // Might have been started by another app
             btAdapter.cancelDiscovery();
 
+            final Fragment fragment = this;
             btScanner.setOnPreferenceClickListener(new Preference.OnPreferenceClickListener() {
                 @Override
                 public boolean onPreferenceClick(Preference preference) {
-                    if (PermissionHelper.requestBluetoothPermission(getActivity())) {
+                    if (PermissionHelper.requestBluetoothPermission(getActivity(), fragment)) {
                         startBluetoothDiscovery();
                     }
                     return true;
@@ -244,6 +247,20 @@ public class BluetoothPreferences extends PreferenceFragment {
         super.onDestroy();
     }
 
+    @Override
+    public void onActivityResult(int requestCode, int resultCode, Intent data) {
+        if (requestCode == PermissionHelper.ENABLE_BLUETOOTH_REQUEST) {
+            if (resultCode == Activity.RESULT_OK) {
+                if (PermissionHelper.requestBluetoothPermission(getActivity(), this)) {
+                    startBluetoothDiscovery();
+                }
+            }
+            else {
+                btScanner.getDialog().dismiss();
+            }
+        }
+    }
+
     private class onClickListenerDeviceSelect implements Preference.OnPreferenceClickListener {
         @Override
         public boolean onPreferenceClick(final Preference preference) {
@@ -267,7 +284,7 @@ public class BluetoothPreferences extends PreferenceFragment {
                 if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                     startBluetoothDiscovery();
                 } else {
-                    Toast.makeText(getActivity().getApplicationContext(), R.string.permission_not_granted, Toast.LENGTH_SHORT).show();
+                    Toast.makeText(getActivity(), R.string.permission_not_granted, Toast.LENGTH_SHORT).show();
                 }
                 break;
             }

android_app/app/src/main/java/com/health/openscale/gui/utils/PermissionHelper.java

@@ -18,6 +18,7 @@ package com.health.openscale.gui.utils;
 import android.Manifest;
 import android.app.Activity;
 import android.app.AlertDialog;
+import android.app.Fragment;
 import android.bluetooth.BluetoothAdapter;
 import android.bluetooth.BluetoothManager;
 import android.content.Context;
@@ -34,24 +35,25 @@ public class PermissionHelper {
     public final static int PERMISSIONS_REQUEST_ACCESS_READ_STORAGE = 2;
     public final static int PERMISSIONS_REQUEST_ACCESS_WRITE_STORAGE = 3;
 
-    public static boolean requestBluetoothPermission(final Activity activity) {
+    public final static int ENABLE_BLUETOOTH_REQUEST = 5;
+
+    public static boolean requestBluetoothPermission(final Activity activity, Fragment fragment) {
         final BluetoothManager bluetoothManager = (BluetoothManager) activity.getSystemService(Context.BLUETOOTH_SERVICE);
         BluetoothAdapter btAdapter = bluetoothManager.getAdapter();
 
         if (btAdapter == null || !btAdapter.isEnabled()) {
-
+            Toast.makeText(activity, "Bluetooth " + activity.getResources().getString(R.string.info_is_not_enable), Toast.LENGTH_SHORT).show();
-            Toast.makeText(activity.getApplicationContext(), "Bluetooth " + activity.getResources().getString(R.string.info_is_not_enable), Toast.LENGTH_SHORT).show();
 
             if (btAdapter != null) {
                 Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
-                activity.startActivity(enableBtIntent);
+                fragment.startActivityForResult(enableBtIntent, ENABLE_BLUETOOTH_REQUEST);
             }
             return false;
         }
 
         // Check if Bluetooth 4.x is available
         if (!activity.getPackageManager().hasSystemFeature(PackageManager.FEATURE_BLUETOOTH_LE)) {
-            Toast.makeText(activity.getApplicationContext(), "Bluetooth 4.x " + activity.getResources().getString(R.string.info_is_not_available), Toast.LENGTH_SHORT).show();
+            Toast.makeText(activity, "Bluetooth 4.x " + activity.getResources().getString(R.string.info_is_not_available), Toast.LENGTH_SHORT).show();
             return false;
          }