Make db querries from ListActivity on background thread

Signed-off-by: Arka Prava Basu <[email protected]>
guardianproject · Sep 2, 2018 · 762f06c · 762f06c
1 parent 8161171
commit 762f06c
Show file tree

Hide file tree

Showing 5 changed files with 64 additions and 62 deletions.
diff --git a/build.gradle b/build.gradle
@@ -148,4 +148,6 @@ dependencies {
     // Room
     implementation "android.arch.persistence.room:runtime:1.1.1"
     kapt "android.arch.persistence.room:compiler:1.1.1"
+    implementation "android.arch.lifecycle:runtime:1.1.1"
+    implementation "android.arch.lifecycle:extensions:1.1.1"
 }
diff --git a/src/main/java/org/havenapp/main/ListActivity.java b/src/main/java/org/havenapp/main/ListActivity.java
@@ -18,6 +18,7 @@
 package org.havenapp.main;
 
 import android.annotation.SuppressLint;
+import android.arch.lifecycle.Observer;
 import android.content.Intent;
 import android.database.sqlite.SQLiteException;
 import android.graphics.Color;
@@ -26,6 +27,7 @@
 import android.os.Build;
 import android.os.Bundle;
 import android.os.Handler;
+import android.support.annotation.NonNull;
 import android.support.design.widget.FloatingActionButton;
 import android.support.design.widget.Snackbar;
 import android.support.v4.content.ContextCompat;
@@ -77,6 +79,21 @@ public class ListActivity extends AppCompatActivity {
 
     private Handler handler = new Handler();
 
+    private Observer<List<Event>> eventListObserver = events -> {
+        if (events != null) {
+            setEventListToRecyclerView(events);
+        }
+    };
+
+    private Observer<Integer> eventCountObserver = count -> {
+        if (count != null && count > events.size()) {
+            fetchEventList();
+            showNonEmptyState();
+        } else if (count != null && count == 0) {
+            showEmptyState();
+        }
+    };
+
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
@@ -150,34 +167,53 @@ public void onClick(View v) {
             showOnboarding();
         }
 
-        try {
-            events = HavenEventDB.getDatabase(this).getEventDAO().getAllEventDesc();
+        initializeRecyclerViewComponents();
 
-            if (events.size() > 0) {
-                findViewById(R.id.empty_view).setVisibility(View.GONE);
-            }
+        fetchEventList();
+    }
 
-            adapter = new EventAdapter(events, resourceManager);
-            recyclerView.setVisibility(View.VISIBLE);
-            recyclerView.setAdapter(adapter);
+    private void initializeRecyclerViewComponents() {
+        adapter = new EventAdapter(events, resourceManager);
+        recyclerView.setVisibility(View.VISIBLE);
+        recyclerView.setAdapter(adapter);
 
+        adapter.SetOnItemClickListener((view, position) -> {
 
-            adapter.SetOnItemClickListener(new EventAdapter.OnItemClickListener() {
-                @Override
-                public void onItemClick(View view, int position) {
+            Intent i = new Intent(ListActivity.this, EventActivity.class);
+            i.putExtra("eventid", events.get(position).getId());
+            modifyPos = position;
 
-                    Intent i = new Intent(ListActivity.this, EventActivity.class);
-                    i.putExtra("eventid", events.get(position).getId());
-                    modifyPos = position;
+            startActivity(i);
+        });
+    }
 
-                    startActivity(i);
-                }
-            });
+    private void setEventListToRecyclerView(@NonNull List<Event> events) {
+        this.events = events;
+
+        if (events.size() > 0) {
+            findViewById(R.id.empty_view).setVisibility(View.GONE);
+        }
+
+        adapter.setEvents(events);
+    }
+
+    private void fetchEventList() {
+        try {
+            HavenEventDB.getDatabase(this).getEventDAO().getAllEventDesc()
+                    .observe(this, eventListObserver);
         } catch (SQLiteException sqe) {
             Log.d(getClass().getName(), "database not yet initiatied", sqe);
         }
+    }
 
+    private void showEmptyState() {
+        recyclerView.setVisibility(View.GONE);
+        findViewById(R.id.empty_view).setVisibility(View.VISIBLE);
+    }
 
+    private void showNonEmptyState() {
+        recyclerView.setVisibility(View.VISIBLE);
+        findViewById(R.id.empty_view).setVisibility(View.GONE);
     }
 
     private void deleteEvent (final Event event, final int position)
@@ -243,50 +279,12 @@ protected void onResume() {
         super.onResume();
 
         resourceManager = new ResourceManager(this);
-        final long newCount = HavenEventDB.getDatabase(this).getEventDAO().count();
-
-        if (newCount > events.size()) {
-            events = HavenEventDB.getDatabase(this).getEventDAO().getAllEventDesc();
-            adapter = new EventAdapter(events, resourceManager);
-            recyclerView.setAdapter(adapter);
-
-            adapter.SetOnItemClickListener(new EventAdapter.OnItemClickListener() {
-                @Override
-                public void onItemClick(View view, int position) {
-
-                    Intent i = new Intent(ListActivity.this, EventActivity.class);
-                    i.putExtra("eventid", events.get(position).getId());
-                    modifyPos = position;
-
-                    startActivity(i);
-                }
-            });
-            /**
-            // Just load the last added note (new)
-            Event event = Event.last(Event.class);
-
-            events.add(0,event);
-            adapter.notifyItemInserted(0);
-            adapter.notifyDataSetChanged();
-
-            initialCount = newCount;
-            **/
-
-            recyclerView.setVisibility(View.VISIBLE);
-            findViewById(R.id.empty_view).setVisibility(View.GONE);
-        }
-        else if (newCount == 0)
-        {
-            recyclerView.setVisibility(View.GONE);
-            findViewById(R.id.empty_view).setVisibility(View.VISIBLE);
-        }
+        HavenEventDB.getDatabase(this).getEventDAO().count().observe(this, eventCountObserver);
 
         if (modifyPos != -1) {
             //Event.set(modifyPos, Event.listAll(Event.class).get(modifyPos));
             adapter.notifyItemChanged(modifyPos);
         }
-
-
     }
 
     @SuppressLint("SimpleDateFormat")
@@ -396,4 +394,4 @@ else if (!TextUtils.isEmpty(preferences.getSmsNumber())) {
 
         }
     }
-}
+}
diff --git a/src/main/java/org/havenapp/main/dao/EventDAO.kt b/src/main/java/org/havenapp/main/dao/EventDAO.kt
@@ -1,5 +1,6 @@
 package org.havenapp.main.dao
 
+import android.arch.lifecycle.LiveData
 import android.arch.persistence.room.*
 import org.havenapp.main.model.Event
 
@@ -25,8 +26,8 @@ interface EventDAO {
     fun getAllEvent() : List<Event>
 
     @Query("SELECT * FROM EVENT ORDER BY ID DESC")
-    fun getAllEventDesc() : List<Event>
+    fun getAllEventDesc() : LiveData<List<Event>>
 
     @Query("SELECT COUNT(*) FROM EVENT")
-    fun count() : Int
+    fun count() : LiveData<Int>
 }
diff --git a/src/main/java/org/havenapp/main/dao/EventTriggerDAO.kt b/src/main/java/org/havenapp/main/dao/EventTriggerDAO.kt
@@ -25,5 +25,5 @@ interface EventTriggerDAO {
     fun getEventTriggerList(eventId: Long?) : MutableList<EventTrigger>
 
     @Query("SELECT * FROM EVENT_TRIGGER")
-    fun getAllEventTriggers() : MutableList<EventTrigger>
-}
+    fun getAllEventTriggers() : MutableList<EventTrigger> // todo remove this for now
+}
diff --git a/src/main/java/org/havenapp/main/ui/EventAdapter.java b/src/main/java/org/havenapp/main/ui/EventAdapter.java
@@ -24,7 +24,7 @@ public class EventAdapter extends RecyclerView.Adapter<EventAdapter.EventVH> {
 
     private OnItemClickListener clickListener;
 
-    public EventAdapter(List<Event> events, @NonNull IResourceManager resourceManager) {
+    public EventAdapter(@NonNull List<Event> events, @NonNull IResourceManager resourceManager) {
         this.events = events;
         this.resourceManager = resourceManager;
     }
@@ -83,5 +83,6 @@ public void SetOnItemClickListener(final OnItemClickListener itemClickListener)
 
     public void setEvents(List<Event> events) {
         this.events = events;
+        notifyDataSetChanged();
     }
 }