Fix NPE when I2PDActivity got garbage collected and i2pdDaemon became null

app/src/main/java/org/purplei2p/i2pd/I2PDActivity.java

@@ -46,9 +46,6 @@ public class I2PDActivity extends Activity {
     public static final int GRACEFUL_DELAY_MILLIS = 10 * 60 * 1000;
     public static final String PACKAGE_URI_SCHEME = "package:";
 
-    private final MakeMeAJobReceiver jobReceiver = isJobServiceApiAvailable() ?
-            new MakeMeAJobReceiver() : null;
-
     private TextView textView;
     private CheckBox HTTPProxyState;
     private CheckBox SOCKSProxyState;
@@ -56,6 +53,9 @@ public class I2PDActivity extends Activity {
     private CheckBox SAMState;
     private CheckBox I2CPState;
 
+    private final MakeMeAJobReceiver jobReceiver = isJobServiceApiAvailable() ?
+            new MakeMeAJobReceiver() : null;
+
     private static volatile DaemonWrapper daemon;
 
     public static DaemonWrapper getDaemon() { return daemon; }
@@ -144,11 +144,16 @@ public class I2PDActivity extends Activity {
             filter.addAction(MakeMeAJobReceiver.MAKEMEAJOB_ACTION);
             registerReceiver(jobReceiver, filter);
 
+            final DaemonWrapper daemon = I2PDActivity.daemon;
+            if (daemon==null) throw new NullPointerException("daemon is null before the job pinger init");
+
             new Thread(() -> {
                 try {
-                    while (getDaemon().getState().needsToBeAlive()) {
+                    // if (daemon==null) throw new NullPointerException("daemon is null at the job pinger init");
+                    while (daemon.getState().needsToBeAlive()) {
                         runOnUiThread(() -> {
                             try {
+                                I2PDActivity.daemon = daemon;
                                 sendBroadcast(new Intent(MakeMeAJobReceiver.MAKEMEAJOB_ACTION));
                             } catch (Throwable tr) {
                                 Log.e(TAG, "", tr);
@@ -276,6 +281,7 @@ public class I2PDActivity extends Activity {
         synchronized (I2PDActivity.class) {
             if (!jobServiceBound && org.purplei2p.i2pd.I2PDActivity.isJobServiceApiAvailable()) {
                 bindService(new Intent(this, MyJobService.class), jobServiceConnection, Context.BIND_AUTO_CREATE);
+                MyJobService.setI2PDDaemon(daemon);
                 jobServiceBound = true;
             }
         }

app/src/main/java/org/purplei2p/i2pd/MyJobService.java

@@ -13,6 +13,12 @@ public class MyJobService extends JobService {
 
     private DaemonWrapper.StateUpdateListener listener;
 
+    public static DaemonWrapper getI2PDDaemon() {
+        DaemonWrapper daemon = I2PDActivity.getDaemon();
+        if (daemon==null) throw new NullPointerException("i2pdDaemon==null");
+        return daemon;
+    }
+
     @Override
     public boolean onStartJob(final JobParameters params) {
         Log.d(TAG,"onStartJob entered");
@@ -26,7 +32,8 @@ public class MyJobService extends JobService {
                 jobFinished(params, false);
             }
         };
-        I2PDActivity.getDaemon().addStateChangeListener(listener);
+
+        getI2PDDaemon().addStateChangeListener(listener);
 
         /*
             "So, the system may kill the process at any time to reclaim memory, and in doing so,
@@ -58,6 +65,6 @@ public class MyJobService extends JobService {
     }
 
     private void removeDaemonStateChangeListener() {
-        I2PDActivity.getDaemon().removeStateChangeListener(listener);
+        getI2PDDaemon().removeStateChangeListener(listener);
     }
 }

app/src/main/java/org/purplei2p/i2pd/receivers/MakeMeAJobReceiver.java

@@ -8,6 +8,7 @@ import android.content.Context;
 import android.content.Intent;
 import android.util.Log;
 
+import org.purplei2p.i2pd.DaemonWrapper;
 import org.purplei2p.i2pd.I2PDActivity;
 import org.purplei2p.i2pd.MyJobService;