Added an initial swipe to refresh tutorial. Small bug fixes.

app/src/main/java/com/afollestad/nocknock/ui/MainActivity.java

@@ -8,8 +8,10 @@ import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
+import android.content.SharedPreferences;
 import android.graphics.Path;
 import android.os.Bundle;
+import android.preference.PreferenceManager;
 import android.support.design.widget.FloatingActionButton;
 import android.support.v4.app.NotificationManagerCompat;
 import android.support.v4.content.ContextCompat;
@@ -94,6 +96,24 @@ public class MainActivity extends AppCompatActivity implements SwipeRefreshLayou
         Inquiry.init(this, DB_NAME, 1);
     }
 
+    private void showRefreshTutorial() {
+        if (mAdapter.getItemCount() == 0) return;
+        final SharedPreferences pr = PreferenceManager.getDefaultSharedPreferences(this);
+        if (pr.getBoolean("shown_swipe_refresh_tutorial", false)) return;
+
+        final View tutorialView = findViewById(R.id.swipeRefreshTutorial);
+        tutorialView.setVisibility(View.VISIBLE);
+        tutorialView.setAlpha(0f);
+        tutorialView.animate().cancel();
+        tutorialView.animate().setDuration(300).alpha(1f).start();
+
+        findViewById(R.id.understoodBtn).setOnClickListener(view -> {
+            view.setOnClickListener(null);
+            findViewById(R.id.swipeRefreshTutorial).setVisibility(View.GONE);
+            pr.edit().putBoolean("shown_swipe_refresh_tutorial", true).commit();
+        });
+    }
+
     @Override
     protected void onResume() {
         super.onResume();
@@ -135,6 +155,7 @@ public class MainActivity extends AppCompatActivity implements SwipeRefreshLayou
         mAdapter.set(models);
         mEmptyText.setVisibility(mAdapter.getItemCount() == 0 ? View.VISIBLE : View.GONE);
         AlarmUtil.setSiteChecks(this, models);
+        showRefreshTutorial();
     }
 
     @Override
@@ -204,7 +225,7 @@ public class MainActivity extends AppCompatActivity implements SwipeRefreshLayou
                             AlarmUtil.setSiteChecks(MainActivity.this, model);
                             checkSite(MainActivity.this, model);
                         });
-            } else if(requestCode == VIEW_SITE_RQ) {
+            } else if (requestCode == VIEW_SITE_RQ) {
                 Inquiry.get()
                         .update(MainActivity.SITES_TABLE_NAME, ServerModel.class)
                         .where("_id = ?", model.id)

app/src/main/java/com/afollestad/nocknock/util/AlarmUtil.java

@@ -52,6 +52,7 @@ public class AlarmUtil {
     }
 
     public static void setSiteChecks(Context context, ServerModel[] sites) {
+        if (sites == null || sites.length == 0) return;
         for (ServerModel site : sites)
             setSiteChecks(context, site);
     }

app/src/main/res/drawable/ic_down_arrow.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="84dp"
+        android:height="84dp"
+        android:viewportWidth="24.0"
+        android:viewportHeight="24.0">
+    <path
+        android:pathData="M20,12l-1.41,-1.41L13,16.17V4h-2v12.17l-5.58,-5.59L4,12l8,8 8,-8z"
+        android:fillColor="#fff"/>
+</vector>

app/src/main/res/layout/activity_main.xml

@@ -43,4 +43,62 @@
         app:rippleColor="#40ffffff"
         app:useCompatPadding="true" />
 
+    <LinearLayout
+        android:id="@+id/swipeRefreshTutorial"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:background="#BF000000"
+        android:orientation="vertical"
+        android:padding="@dimen/content_inset"
+        android:visibility="gone">
+
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:orientation="horizontal"
+            android:weightSum="2">
+
+            <ImageView
+                android:layout_width="0dp"
+                android:layout_height="wrap_content"
+                android:layout_weight="1"
+                android:scaleType="center"
+                android:src="@drawable/ic_down_arrow"
+                android:tint="#fff"
+                tools:ignore="ContentDescription" />
+
+            <ImageView
+                android:layout_width="0dp"
+                android:layout_height="wrap_content"
+                android:layout_weight="1"
+                android:scaleType="center"
+                android:src="@drawable/ic_down_arrow"
+                android:tint="#fff"
+                tools:ignore="ContentDescription" />
+
+        </LinearLayout>
+
+        <TextView
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_gravity="center_horizontal"
+            android:layout_marginTop="@dimen/content_inset_more"
+            android:fontFamily="sans-serif-medium"
+            android:gravity="center"
+            android:lineSpacingMultiplier="1.6"
+            android:text="@string/swipe_refresh_hint"
+            android:textColor="#fff"
+            android:textSize="@dimen/medium_text_size" />
+
+        <Button
+            android:id="@+id/understoodBtn"
+            android:layout_width="@dimen/tutorial_button_width"
+            android:layout_height="@dimen/button_height"
+            android:layout_gravity="center_horizontal"
+            android:layout_marginTop="@dimen/content_inset_double"
+            android:text="@string/understood"
+            android:theme="@style/AccentButton" />
+
+    </LinearLayout>
+
 </FrameLayout>

app/src/main/res/values/dimens.xml

@@ -17,5 +17,6 @@
     <dimen name="fab_elevation">4dp</dimen>
     <dimen name="fab_elevation_pressed">8dp</dimen>
     <dimen name="button_height">52dp</dimen>
+    <dimen name="tutorial_button_width">300dp</dimen>
 
 </resources>

app/src/main/res/values/strings.xml

@@ -42,6 +42,8 @@
     <string name="none">None</string>
 
     <string name="refresh_status">Refresh Status</string>
+    <string name="swipe_refresh_hint">Drag the list down to manually refresh site statuses! Otherwise, they will be updated automatically in the background on chosen intervals.</string>
+    <string name="understood">Understood!</string>
 
     <string-array name="interval_options">
         <item>Minute(s)</item>

app/src/main/res/values/styles.xml

@@ -27,4 +27,9 @@
         <item name="android:windowBackground">@android:color/transparent</item>
     </style>
 
+    <style name="AccentButton" parent="Widget.AppCompat.Button.Colored">
+        <item name="android:textColor">#fff</item>
+        <item name="android:colorButtonNormal">@color/colorAccent</item>
+    </style>
+
 </resources>