Move database operations to a background thread

app/src/main/java/com/example/vu/android/empowerplant/AppDatabase.java

@@ -17,7 +17,6 @@ public static synchronized AppDatabase getInstance(Context context){
         if (INSTANCE == null){
             INSTANCE = Room.databaseBuilder(context.getApplicationContext(), 
             AppDatabase.class,"AppDatabase")
-            .allowMainThreadQueries()
             .build();
         }
         return INSTANCE;

app/src/main/java/com/example/vu/android/empowerplant/EmpowerPlantActivity.java

@@ -12,6 +12,8 @@
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Random;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
 
 import com.example.vu.android.MainActivity;
 import com.example.vu.android.MyBaseActivity;
@@ -24,14 +26,22 @@
     static boolean active = false;
     MainFragment fragment = null;
     TextView textCartItemCount;
+    private ExecutorService executorService;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
 
         setContentView(R.layout.activity_empowerplant);
-        dbQuery();
-        addAttachment(true);
+
+        executorService = Executors.newSingleThreadExecutor();
+
+        // Move blocking operations to a background thread
+        executorService.submit(() -> {
+            dbQuery();
+            addAttachment(true);
+        });
+
         checkRelease();
         this.loadFragmentList();
     }
@@ -127,4 +137,12 @@
         super.onStop();
         active = false;
     }
+
+    @Override
+    protected void onDestroy() {
+        super.onDestroy();
+        if (executorService != null) {
+            executorService.shutdown();
+        }
+    }
 }