Detcach samples from the session after querying, to save memory

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/devices/AbstractSampleProvider.java

@@ -93,9 +93,20 @@ public abstract class AbstractSampleProvider<T extends AbstractActivitySample> i
         for (T sample : samples) {
             sample.setProvider(this);
         }
+        detachFromSession();
         return samples;
     }
 
+    /**
+     * Detaches all samples of this type from the session. Changes to them may not be
+     * written back to the database.
+     *
+     * Subclasses should call this method after performing custom queries.
+     */
+    protected void detachFromSession() {
+        getSampleDao().detachAll();
+    }
+
     private WhereCondition[] getClauseForActivityType(QueryBuilder qb, int activityTypes) {
         if (activityTypes == ActivityKind.TYPE_ALL) {
             return NO_CONDITIONS;

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/devices/SampleProvider.java

@@ -9,6 +9,10 @@ import nodomain.freeyourgadget.gadgetbridge.entities.AbstractActivitySample;
 /**
  * Interface to retrieve samples from the database, and also create and add samples to the database.
  * There are multiple device specific implementations, this interface defines the generic access.
+ *
+ * Note that the provided samples must typically be considered read-only, because they are immediately
+ * removed from the session before they are returned.
+ *
  * @param <T> the device/provider specific sample type (must extend AbstractActivitySample)
  */
 public interface SampleProvider<T extends AbstractActivitySample> {

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/devices/pebble/PebbleHealthSampleProvider.java

@@ -57,6 +57,7 @@ public class PebbleHealthSampleProvider extends AbstractSampleProvider<PebbleHea
                 }
             }
         }
+        detachFromSession();
         return samples;
     }
 

app/src/test/java/nodomain/freeyourgadget/gadgetbridge/database/EntitiesTest.java

@@ -50,6 +50,7 @@ public class EntitiesTest {
 
     @Before
     public void setUp() throws GBException {
+// doesn't work with Robolectric yet
 //        dbHandler = GBApplication.acquireDB();
 //        daoSession = dbHandler.getDaoSession();
         DaoMaster.DevOpenHelper openHelper = new DaoMaster.DevOpenHelper(app, null, null);