Keep the job and state through a recreate

app/src/main/java/in/co/gorest/grblcontroller/BluetoothConnectionActivity.java

@@ -144,14 +144,15 @@ public void onRequestPermissionsResult(int requestCode, String[] permissions, in
     @Override
     public void onDestroy(){
         super.onDestroy();
-        onGcodeCommandReceived("$10=1");
+        // On a recreate keep the connection: a connected service is started, so it outlives the unbind.
+        if(isFinishing()) onGcodeCommandReceived("$10=1");
         if(mBound){
             grblBluetoothSerialService.setMessageHandler(null);
             unbindService(serviceConnection);
             mBound = false;
         }
 
-        stopService(new Intent(this, GrblBluetoothSerialService.class));
+        if(isFinishing()) stopService(new Intent(this, GrblBluetoothSerialService.class));
         EventBus.getDefault().unregister(this);
     }
 
@@ -271,6 +272,9 @@ public void onServiceConnected(ComponentName className, IBinder service) {
             mBound = true;
             grblBluetoothSerialService.setMessageHandler(grblServiceMessageHandler);
             grblBluetoothSerialService.setStatusUpdatePoolInterval(Long.parseLong(sharedPref.getString(getString(R.string.preference_update_pool_interval), String.valueOf(Constants.GRBL_STATUS_UPDATE_INTERVAL))));
+            // After a recreate the link may still be up; show it. STATE_NONE is left out, as it posts "connection lost".
+            int state = grblBluetoothSerialService.getState();
+            if(state == GrblBluetoothSerialService.STATE_CONNECTED || state == GrblBluetoothSerialService.STATE_CONNECTING) onBluetoothStateChange(state);
         }
 
         @Override

app/src/main/java/in/co/gorest/grblcontroller/GrblActivity.java

@@ -105,6 +105,13 @@ public abstract class GrblActivity extends AppCompatActivity implements BaseFrag
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
+        // A fresh start gets fresh state; a recreate (rotation, fold, resize) keeps it. Reset here, not
+        // in onDestroy: a closing activity is destroyed after the new one has read these objects.
+        if(savedInstanceState == null){
+            ConsoleLoggerListener.resetClass();
+            FileSenderListener.resetClass();
+            MachineStatusListener.resetClass();
+        }
         setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
 
         ActivityMainBinding binding = DataBindingUtil.setContentView(this, R.layout.activity_main);
@@ -130,7 +137,10 @@ protected void onCreate(Bundle savedInstanceState) {
 
         Iconify.with(new FontAwesomeModule());
         setupTabLayout();
-        checkPowerManagement();
+        // Ask once per start. On a recreate the dialog would cover the Stop button of a running job.
+        if(savedInstanceState == null) checkPowerManagement();
+        // A recreate during a job gets a new window, so set keep screen on again.
+        if(FileStreamerIntentService.getIsServiceRunning()) OnStreamingStartEvent(new StreamingStartedEvent());
 
         if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU
                 && ActivityCompat.checkSelfPermission(this, android.Manifest.permission.POST_NOTIFICATIONS) != PackageManager.PERMISSION_GRANTED){
@@ -160,10 +170,8 @@ private boolean hasPaidVersion() {
     public void onDestroy(){
         super.onDestroy();
 
-        stopService(new Intent(this, FileStreamerIntentService.class));
-        ConsoleLoggerListener.resetClass();
-        FileSenderListener.resetClass();
-        MachineStatusListener.resetClass();
+        // Only a real exit stops the job. A recreate must not stop it in the middle.
+        if(isFinishing()) stopService(new Intent(this, FileStreamerIntentService.class));
         isAppRunning = false;
         getWindow().clearFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
         lastToast = null;

app/src/main/java/in/co/gorest/grblcontroller/UsbConnectionActivity.java

@@ -92,14 +92,15 @@ public void onStart(){
     @Override
     public void onDestroy() {
         super.onDestroy();
-        onGcodeCommandReceived("$10=1");
+        // On a recreate keep the connection: the service is started, so it outlives the unbind.
+        if(isFinishing()) onGcodeCommandReceived("$10=1");
         unregisterReceiver(mUsbReceiver);
         if(mBound){
             grblUsbSerialService.setMessageHandler(null);
             unbindService(usbConnection);
             mBound = false;
         }
-        stopService(new Intent(this, GrblUsbSerialService.class));
+        if(isFinishing()) stopService(new Intent(this, GrblUsbSerialService.class));
         EventBus.getDefault().unregister(this);
     }
 
@@ -232,6 +233,8 @@ public void onServiceConnected(ComponentName className, IBinder service) {
             mBound = true;
             grblUsbSerialService.setMessageHandler(grblServiceMessageHandler);
             grblUsbSerialService.setStatusUpdatePoolInterval(Long.parseLong(sharedPref.getString(getString(R.string.preference_update_pool_interval), String.valueOf(Constants.GRBL_STATUS_UPDATE_INTERVAL))));
+            // After a recreate the port may still be open; show it.
+            if(grblUsbSerialService.isSerialPortConnected() && getSupportActionBar() != null) getSupportActionBar().setSubtitle(getString(R.string.text_connected));
         }
 
         @Override

app/src/main/java/in/co/gorest/grblcontroller/service/GrblUsbSerialService.java

@@ -115,7 +115,7 @@ public class GrblUsbSerialService extends Service {
     private UsbDeviceConnection connection;
     private UsbSerialDevice serialPort;
 
-    private boolean serialPortConnected;
+    private volatile boolean serialPortConnected;
     public static volatile boolean isGrblFound = false;
 
     private SerialUsbCommunicationHandler serialUsbCommunicationHandler;
@@ -167,6 +167,8 @@ public void onDestroy() {
         EventBus.getDefault().unregister(this);
     }
 
+    public boolean isSerialPortConnected(){ return serialPortConnected; }
+
     public void serialWriteByte(byte b){
         byte[] c = {b};
         serialWriteBytes(c);