Create empty view for RecyclerViewFragment

app/src/main/java/com/philliphsu/clock2/RecyclerViewFragment.java

@@ -1,7 +1,10 @@
 package com.philliphsu.clock2;
 
+import android.graphics.drawable.Drawable;
 import android.os.Bundle;
+import android.support.annotation.DrawableRes;
 import android.support.annotation.Nullable;
+import android.support.annotation.StringRes;
 import android.support.v4.app.LoaderManager;
 import android.support.v4.content.Loader;
 import android.support.v7.widget.LinearLayoutManager;
@@ -9,8 +12,10 @@ import android.support.v7.widget.RecyclerView;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
+import android.widget.TextView;
 
 import com.philliphsu.clock2.alarms.ScrollHandler;
+import com.philliphsu.clock2.aospdatetimepicker.Utils;
 import com.philliphsu.clock2.model.BaseItemCursor;
 import com.philliphsu.clock2.model.ObjectWithId;
 
@@ -34,7 +39,12 @@ public abstract class RecyclerViewFragment<
 
     // TODO: Rename id to recyclerView?
     // TODO: Rename variable to mRecyclerView?
-    @Bind(R.id.list) RecyclerView mList;
+    @Bind(R.id.list)
+    RecyclerView mList;
+
+    @Nullable // Subclasses are not required to use the default content layout, so this may not be present.
+    @Bind(R.id.empty_view)
+    TextView mEmptyView;
 
     public abstract void onFabClick();
 
@@ -51,6 +61,33 @@ public abstract class RecyclerViewFragment<
      */
     protected abstract A onCreateAdapter();
 
+    /**
+     * @return a resource to a String that will be displayed when the list is empty
+     */
+    @StringRes
+    protected int emptyMessage() {
+        // The reason this isn't abstract is so we don't require subclasses that
+        // don't have an empty view to implement this.
+        return 0;
+    }
+
+    /**
+     * @return a resource to a Drawable that will be displayed when the list is empty
+     */
+    @DrawableRes
+    protected int emptyMessageIcon() {
+        // TODO: If this is the same for all RecyclerViewFragments, then why not just specify
+        // the compound drawable in XML?
+        return R.drawable.ic_empty_list_96dp;
+    }
+
+    /**
+     * @return whether the list should show an empty view when its adapter has an item count of zero
+     */
+    protected boolean hasEmptyView() {
+        return true;
+    }
+
     /**
      * @return the adapter instance created from {@link #onCreateAdapter()}
      */
@@ -73,6 +110,13 @@ public abstract class RecyclerViewFragment<
         View view = super.onCreateView(inflater, container, savedInstanceState);
         mList.setLayoutManager(getLayoutManager());
         mList.setAdapter(mAdapter = onCreateAdapter());
+        if (hasEmptyView() && mEmptyView != null) {
+            // Configure the empty view, even if there currently are items.
+            mEmptyView.setText(emptyMessage());
+            int iconColor = Utils.getTextColorFromThemeAttr(getActivity(), R.attr.themedIconTint);
+            Drawable emptyMessageIcon = Utils.getTintedDrawable(getActivity(), emptyMessageIcon(), iconColor);
+            mEmptyView.setCompoundDrawablesRelativeWithIntrinsicBounds(null, emptyMessageIcon, null, null);
+        }
         return view;
     }
 
@@ -87,6 +131,12 @@ public abstract class RecyclerViewFragment<
     @Override
     public void onLoadFinished(Loader<C> loader, C data) {
         mAdapter.swapCursor(data);
+        if (hasEmptyView() && mEmptyView != null) {
+            // TODO: Last I checked after a fresh install, this worked fine.
+            // However, previous attempts (without fresh installs) didn't hide the empty view
+            // upon an item being added. Verify this is no longer the case.
+            mEmptyView.setVisibility(mAdapter.getItemCount() == 0 ? View.VISIBLE : View.GONE);
+        }
         // This may have been a requery due to content change. If the change
         // was an insertion, scroll to the last modified alarm.
         performScrollToStableId();

app/src/main/java/com/philliphsu/clock2/alarms/AlarmsFragment.java

@@ -146,6 +146,11 @@ public class AlarmsFragment extends RecyclerViewFragment<
         return new AlarmsCursorAdapter(this, mAlarmController);
     }
 
+    @Override
+    protected int emptyMessage() {
+        return R.string.empty_alarms_container;
+    }
+
     // TODO: We're not using EditAlarmActivity anymore, so move this logic somewhere else.
     // We also don't need to delay the change to get animations working.
     @Override

app/src/main/java/com/philliphsu/clock2/stopwatch/StopwatchFragment.java

@@ -160,6 +160,11 @@ public class StopwatchFragment extends RecyclerViewFragment<
                 + ", mPauseTime = " + mPauseTime);
     }
 
+    @Override
+    protected boolean hasEmptyView() {
+        return false;
+    }
+
     @Override
     public Loader<LapCursor> onCreateLoader(int id, Bundle args) {
         return new LapsCursorLoader(getActivity());

app/src/main/java/com/philliphsu/clock2/timers/TimersFragment.java

@@ -102,6 +102,11 @@ public class TimersFragment extends RecyclerViewFragment<
         }
     }
 
+    @Override
+    protected int emptyMessage() {
+        return R.string.empty_timers_container;
+    }
+
     @Override
     public Loader<TimerCursor> onCreateLoader(int id, Bundle args) {
         return new TimersListCursorLoader(getActivity());

app/src/main/res/drawable/ic_empty_list_96dp.xml

@@ -0,0 +1,4 @@
+<vector android:height="96dp" android:viewportHeight="24.0"
+    android:viewportWidth="24.0" android:width="96dp" xmlns:android="http://schemas.android.com/apk/res/android">
+    <path android:fillColor="#FFFFFF" android:pathData="M14.59,8L12,10.59 9.41,8 8,9.41 10.59,12 8,14.59 9.41,16 12,13.41 14.59,16 16,14.59 13.41,12 16,9.41 14.59,8zM12,2C6.47,2 2,6.47 2,12s4.47,10 10,10 10,-4.47 10,-10S17.53,2 12,2zM12,20c-4.41,0 -8,-3.59 -8,-8s3.59,-8 8,-8 8,3.59 8,8 -3.59,8 -8,8z"/>
+</vector>

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

@@ -1,21 +1,36 @@
 <?xml version="1.0" encoding="utf-8"?>
-<!-- clipToPadding specifies whether padding should cut into the
-   - view bounds, and hence into the children. To us, setting
-   - this to false has the effect of padding the bottom with
-   - extra space so the FAB isn't covering the last item
-   - when we scroll to it.
-   -
-   - An outsideOverlay scrollbarStyle means the scrollbar is drawn
-   - outside of the clipping boundary due to padding, and is laid over
-   - the RecyclerView, rather than being inside of its container (which
-   - mandates it being inset and adding to the view's padding).
- -->
-<android.support.v7.widget.RecyclerView
-    android:id="@+id/list"
-    xmlns:android="http://schemas.android.com/apk/res/android"
+<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
-    android:layout_height="match_parent"
-    android:scrollbars="vertical"
-    android:scrollbarStyle="outsideOverlay"
-    android:clipToPadding="false"
-    android:paddingBottom="@dimen/fab_total_height"/>
+    android:layout_height="match_parent">
+
+    <!-- clipToPadding specifies whether padding should cut into the
+       - view bounds, and hence into the children. To us, setting
+       - this to false has the effect of padding the bottom with
+       - extra space so the FAB isn't covering the last item
+       - when we scroll to it.
+       -
+       - An outsideOverlay scrollbarStyle means the scrollbar is drawn
+       - outside of the clipping boundary due to padding, and is laid over
+       - the RecyclerView, rather than being inside of its container (which
+       - mandates it being inset and adding to the view's padding).
+     -->
+    <android.support.v7.widget.RecyclerView
+        android:id="@+id/list"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:scrollbars="vertical"
+        android:scrollbarStyle="outsideOverlay"
+        android:clipToPadding="false"
+        android:paddingBottom="@dimen/fab_total_height"/>
+
+    <TextView
+        android:id="@+id/empty_view"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_gravity="center"
+        android:gravity="center"
+        android:textSize="@dimen/text_size_headline"
+        android:drawablePadding="@dimen/text_compound_drawable_padding"
+        android:visibility="gone"/>
+
+</FrameLayout>

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

@@ -200,4 +200,7 @@
 
     <string name="pause">Pause</string>
     <string name="resume">Resume</string>
+
+    <string name="empty_alarms_container">No alarms added</string>
+    <string name="empty_timers_container">No timers added</string>
 </resources>