Added SectionIndicator for viewing section while fast scrolling

Author: danoz73

Application/src/main/java/com/example/recyclerviewfastscroller/MainActivity.java

@@ -25,11 +25,14 @@
 import android.view.MenuItem;
 
 import com.example.android.recyclerview.R;
-import com.example.recyclerviewfastscroller.fragment.RecyclerViewFragment;
-import com.example.recyclerviewfastscroller.fragment.RecyclerViewWithSectionsFragment;
+import com.example.recyclerviewfastscroller.fragment.RecyclerViewWithFastScrollerFragment;
+import com.example.recyclerviewfastscroller.fragment.RecyclerViewWithSectionIndicatorFragment;
+import com.example.recyclerviewfastscroller.ui.scroller.sectionindicator.title.SectionTitleIndicator;
+import com.example.recyclerviewfastscroller.ui.scroller.vertical.VerticalRecyclerViewFastScroller;
 
 /**
- * Simple activity for displaying the {@link RecyclerViewFragment}
+ * Simple activity for displaying an example of the {@link VerticalRecyclerViewFastScroller} as well as
+ * {@link SectionTitleIndicator} usage paired with the fast scroller
  */
 public class MainActivity extends FragmentActivity {
 
@@ -39,7 +42,7 @@ protected void onCreate(Bundle savedInstanceState) {
         setContentView(R.layout.activity_main);
 
         if (savedInstanceState == null) {
-            RecyclerViewFragment fragment = new RecyclerViewFragment();
+            RecyclerViewWithFastScrollerFragment fragment = new RecyclerViewWithFastScrollerFragment();
             replaceCurrentFragment(fragment);
         }
     }
@@ -61,11 +64,16 @@ public boolean onCreateOptionsMenu(Menu menu) {
     public boolean onOptionsItemSelected(MenuItem item) {
         // Handle item selection
         switch (item.getItemId()) {
+            case R.id.menu_item_list_no_section_indicator:
+                RecyclerViewWithFastScrollerFragment simpleFastScrollerFragment = new RecyclerViewWithFastScrollerFragment();
+                replaceCurrentFragment(simpleFastScrollerFragment);
+                return true;
             case R.id.menu_item_list_with_sections:
-                RecyclerViewWithSectionsFragment sectionsFragment = new RecyclerViewWithSectionsFragment();
+                RecyclerViewWithSectionIndicatorFragment sectionsFragment = new RecyclerViewWithSectionIndicatorFragment();
                 replaceCurrentFragment(sectionsFragment);
                 return true;
             default:
                 return super.onOptionsItemSelected(item);
         }
-    }}
+    }
+}

Application/src/main/java/com/example/recyclerviewfastscroller/data/ColorData.java

@@ -0,0 +1,30 @@
+package com.example.recyclerviewfastscroller.data;
+
+import android.support.annotation.NonNull;
+
+/**
+ * Data object representing a color
+ */
+public class ColorData {
+
+    private final int mColorInt;
+    private final ColorGroup mColorGroup;
+
+    public ColorData(int colorInt, @NonNull ColorGroup colorGroup) {
+        mColorInt = colorInt;
+        mColorGroup = colorGroup;
+    }
+
+    public int getIntValue() {
+        return mColorInt;
+    }
+
+    public ColorGroup getColorGroup() {
+        return mColorGroup;
+    }
+
+    @Override
+    public String toString() {
+        return String.format("#%06X", (0xFFFFFF & mColorInt));
+    }
+}

Application/src/main/java/com/example/recyclerviewfastscroller/data/ColorDataSet.java

@@ -0,0 +1,38 @@
+package com.example.recyclerviewfastscroller.data;
+
+import android.graphics.Color;
+
+/**
+ * Dummy dataset of N {@link ColorData} objects
+ */
+public class ColorDataSet {
+
+    private static final int DATA_SET_SIZE = 100;
+    private static final float NUM_HUES = 359;
+    private static final ColorData[] mColors = new ColorData[DATA_SET_SIZE];
+
+    public ColorDataSet() {
+        this(new ColorGroupCalculator());
+    }
+
+    private ColorDataSet(ColorGroupCalculator colorGroupCalculator) {
+        for (int i = 0; i < mColors.length; i++) {
+            mColors[i] = generateNewColor(i, mColors.length, colorGroupCalculator);
+        }
+    }
+
+    private ColorData generateNewColor(int position, int numColors, ColorGroupCalculator colorGroupCalculator) {
+        float positionBasedHue = position * (NUM_HUES / numColors);
+        int color = Color.HSVToColor(new float[] {positionBasedHue, 1, 1});
+        return new ColorData(color, colorGroupCalculator.getColorGroup(positionBasedHue));
+    }
+
+    public int getSize() {
+        return mColors.length;
+    }
+
+    public ColorData get(int position) {
+        return mColors[position];
+    }
+
+}

Application/src/main/java/com/example/recyclerviewfastscroller/data/ColorGroup.java

@@ -0,0 +1,41 @@
+package com.example.recyclerviewfastscroller.data;
+
+import android.graphics.Color;
+
+/**
+ * Coarse groupings of colors by hue
+ */
+public enum ColorGroup {
+    RED_UPPER (345, 360, "Red"),
+    PINK (300, RED_UPPER.mMinimumHue, "Pink"),
+    PURPLE (260, PINK.mMinimumHue, "Purple"),
+    BLUE (175, PURPLE.mMinimumHue, "Blue"),
+    GREEN (70, BLUE.mMinimumHue, "Green"),
+    YELLOW (50, GREEN.mMinimumHue, "Yellow"),
+    ORANGE (25, YELLOW.mMinimumHue, "Orange"),
+    RED_LOWER (0, ORANGE.mMinimumHue, "Red"),
+    ;
+
+    private final int mMinimumHue, mMaximumHue;
+    private final int mIntegerRepresentation;
+    private final String mName;
+
+    ColorGroup(int minimumHue, int maximumHue, String groupName) {
+        mMinimumHue = minimumHue;
+        mMaximumHue = maximumHue;
+        mName = groupName;
+        mIntegerRepresentation = Color.HSVToColor(new float[] { (maximumHue + minimumHue) / 2, 1, 1});
+    }
+
+    public String getName() {
+        return mName;
+    }
+
+    public boolean containsHue(int hue) {
+        return (hue >= mMinimumHue && hue < mMaximumHue);
+    }
+
+    public int getAsColor() {
+        return mIntegerRepresentation;
+    }
+}

Application/src/main/java/com/example/recyclerviewfastscroller/data/ColorGroupCalculator.java

@@ -0,0 +1,20 @@
+package com.example.recyclerviewfastscroller.data;
+
+import android.support.annotation.NonNull;
+
+/**
+ * Allow for finding a color group based on a hue
+ */
+class ColorGroupCalculator {
+
+    @NonNull
+    public ColorGroup getColorGroup(float hue) {
+        for (ColorGroup group : ColorGroup.values()) {
+            if (group.containsHue((int) hue)) {
+                return group;
+            }
+        }
+
+        throw new NullPointerException("Could not classify hue into Color Group!");
+    }
+}

Application/src/main/java/com/example/recyclerviewfastscroller/fragment/RecyclerViewFragment.java renamed to Application/src/main/java/com/example/recyclerviewfastscroller/fragment/RecyclerViewWithFastScrollerFragment.java

@@ -25,16 +25,14 @@
 import android.view.ViewGroup;
 
 import com.example.android.recyclerview.R;
+import com.example.recyclerviewfastscroller.data.ColorDataSet;
 import com.example.recyclerviewfastscroller.recyclerview.ColorfulAdapter;
 import com.example.recyclerviewfastscroller.ui.scroller.vertical.VerticalRecyclerViewFastScroller;
 
 /**
  * Adapted from sample code that demonstrates the use of {@link RecyclerView} with a {@link LinearLayoutManager}
  */
-public class RecyclerViewFragment extends Fragment {
-
-    private static final String TAG = "RecyclerViewFragment";
-    private static final int DATASET_COUNT = 100;
+public class RecyclerViewWithFastScrollerFragment extends Fragment {
 
     @Override
     public void onCreate(Bundle savedInstanceState) {
@@ -44,16 +42,16 @@ public void onCreate(Bundle savedInstanceState) {
     @Override
     public View onCreateView(LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
-        View rootView = inflater.inflate(R.layout.recycler_view_frag, container, false);
+        View rootView = inflater.inflate(R.layout.recycler_view_with_fast_scroller_fragment, container, false);
 
-        RecyclerView recyclerView = (RecyclerView) rootView.findViewById(R.id.recyclerView);
+        RecyclerView recyclerView = (RecyclerView) rootView.findViewById(R.id.recycler_view);
         VerticalRecyclerViewFastScroller fastScroller = (VerticalRecyclerViewFastScroller) rootView.findViewById(R.id.fast_scroller);
         fastScroller.setRecyclerView(recyclerView);
         recyclerView.setOnScrollListener(fastScroller.getOnScrollListener());
 
         setRecyclerViewLayoutManager(recyclerView);
 
-        RecyclerView.Adapter adapter = new ColorfulAdapter(getDummyDataSet());
+        RecyclerView.Adapter adapter = new ColorfulAdapter(new ColorDataSet());
         recyclerView.setAdapter(adapter);
 
         return rootView;
@@ -77,14 +75,4 @@ public void setRecyclerViewLayoutManager(RecyclerView recyclerView) {
         recyclerView.scrollToPosition(scrollPosition);
     }
 
-    /**
-     * Generates Strings for RecyclerView's adapter. This data would usually come from somewhere...
-     */
-    private String[] getDummyDataSet() {
-        String[] data = new String[DATASET_COUNT];
-        for (int i = 0; i < DATASET_COUNT; i++) {
-            data[i] = "This is element #" + i;
-        }
-        return data;
-    }
 }

Application/src/main/java/com/example/recyclerviewfastscroller/fragment/RecyclerViewWithSectionsFragment.java renamed to Application/src/main/java/com/example/recyclerviewfastscroller/fragment/RecyclerViewWithSectionIndicatorFragment.java

@@ -1,19 +1,3 @@
-/*
-* Copyright (C) 2014 The Android Open Source Project
-*
-* Licensed under the Apache License, Version 2.0 (the "License");
-* you may not use this file except in compliance with the License.
-* You may obtain a copy of the License at
-*
-*      http://www.apache.org/licenses/LICENSE-2.0
-*
-* Unless required by applicable law or agreed to in writing, software
-* distributed under the License is distributed on an "AS IS" BASIS,
-* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-* See the License for the specific language governing permissions and
-* limitations under the License.
-*/
-
 package com.example.recyclerviewfastscroller.fragment;
 
 import android.os.Bundle;
@@ -25,16 +9,15 @@
 import android.view.ViewGroup;
 
 import com.example.android.recyclerview.R;
+import com.example.recyclerviewfastscroller.data.ColorDataSet;
 import com.example.recyclerviewfastscroller.recyclerview.ColorfulAdapter;
+import com.example.recyclerviewfastscroller.ui.scroller.sectionindicator.title.SectionTitleIndicator;
 import com.example.recyclerviewfastscroller.ui.scroller.vertical.VerticalRecyclerViewFastScroller;
 
 /**
  * Adapted from sample code that demonstrates the use of {@link RecyclerView} with a {@link LinearLayoutManager}
  */
-public class RecyclerViewWithSectionsFragment extends Fragment {
-
-    private static final String TAG = "RecyclerViewFragment";
-    private static final int DATASET_COUNT = 100;
+public class RecyclerViewWithSectionIndicatorFragment extends Fragment {
 
     @Override
     public void onCreate(Bundle savedInstanceState) {
@@ -44,17 +27,23 @@ public void onCreate(Bundle savedInstanceState) {
     @Override
     public View onCreateView(LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
-        View rootView = inflater.inflate(R.layout.recycler_view_frag, container, false);
+        ViewGroup rootView = (ViewGroup) inflater.inflate(R.layout.recycler_view_with_fast_scroller_section_title_indicator_fragment, container, false);
+
+        RecyclerView recyclerView = (RecyclerView) rootView.findViewById(R.id.recycler_view);
+        RecyclerView.Adapter adapter = new ColorfulAdapter(new ColorDataSet());
+        recyclerView.setAdapter(adapter);
 
-        RecyclerView recyclerView = (RecyclerView) rootView.findViewById(R.id.recyclerView);
-        VerticalRecyclerViewFastScroller fastScroller = (VerticalRecyclerViewFastScroller) rootView.findViewById(R.id.fast_scroller);
+        VerticalRecyclerViewFastScroller fastScroller =
+                (VerticalRecyclerViewFastScroller) rootView.findViewById(R.id.fast_scroller);
         fastScroller.setRecyclerView(recyclerView);
+
         recyclerView.setOnScrollListener(fastScroller.getOnScrollListener());
 
-        setRecyclerViewLayoutManager(recyclerView);
+        SectionTitleIndicator sectionTitleIndicator =
+                (SectionTitleIndicator) rootView.findViewById(R.id.fast_scroller_section_title_popup);
+        fastScroller.setSectionIndicator(sectionTitleIndicator);
 
-        RecyclerView.Adapter adapter = new ColorfulAdapter(getDummyDataSet());
-        recyclerView.setAdapter(adapter);
+        setRecyclerViewLayoutManager(recyclerView);
 
         return rootView;
     }
@@ -77,14 +66,4 @@ public void setRecyclerViewLayoutManager(RecyclerView recyclerView) {
         recyclerView.scrollToPosition(scrollPosition);
     }
 
-    /**
-     * Generates Strings for RecyclerView's adapter. This data would usually come from somewhere...
-     */
-    private String[] getDummyDataSet() {
-        String[] data = new String[DATASET_COUNT];
-        for (int i = 0; i < DATASET_COUNT; i++) {
-            data[i] = "This is element #" + i;
-        }
-        return data;
-    }
 }

Application/src/main/java/com/example/recyclerviewfastscroller/recyclerview/ColorfulAdapter.java

@@ -21,18 +21,20 @@
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
+import android.widget.SectionIndexer;
 import android.widget.TextView;
 
 import com.example.android.recyclerview.R;
+import com.example.recyclerviewfastscroller.data.ColorData;
+import com.example.recyclerviewfastscroller.data.ColorDataSet;
+import com.example.recyclerviewfastscroller.data.ColorGroup;
 
 /**
  * Provide views to RecyclerView with data from mDataSet.
  */
-public class ColorfulAdapter extends RecyclerView.Adapter<ColorfulAdapter.ViewHolder> {
+public class ColorfulAdapter extends RecyclerView.Adapter<ColorfulAdapter.ViewHolder> implements SectionIndexer {
 
-    private static final float NUM_HUES = 359f;
-
-    private String[] mDataSet;
+    private ColorDataSet mDataSet;
 
     /**
      * Provide a reference to the type of views that you are using (custom ViewHolder)
@@ -60,10 +62,10 @@ public TextView getTextView() {
     /**
      * Initialize the dataset of the Adapter.
      *
-     * @param dataSet String[] containing the data to populate views to be used by RecyclerView.
+     * @param data String[] containing the data to populate views to be used by RecyclerView.
      */
-    public ColorfulAdapter(String[] dataSet) {
-        mDataSet = dataSet;
+    public ColorfulAdapter(ColorDataSet data) {
+        mDataSet = data;
     }
 
     // Create new views (invoked by the layout manager)
@@ -78,15 +80,35 @@ public ViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) {
     public void onBindViewHolder(ViewHolder viewHolder, final int position) {
         // Get element from your dataset at this position and replace the contents of the view
         // with that element
-        float positionBasedHue = position * (NUM_HUES / mDataSet.length);
-        viewHolder.itemView.setBackgroundColor(Color.HSVToColor(new float[] {positionBasedHue, 1, 1}));
-        viewHolder.getTextView().setText(mDataSet[position]);
+        ColorData color = mDataSet.get(position);
+        viewHolder.itemView.setBackgroundColor(color.getIntValue());
+        viewHolder.getTextView().setText(mDataSet.get(position).toString());
     }
 
     // Return the size of your dataset (invoked by the layout manager)
     @Override
     public int getItemCount() {
-        return mDataSet.length;
+        return mDataSet.getSize();
+    }
+
+    @Override
+    public Object[] getSections() {
+        return ColorGroup.values();
+    }
+
+    @Override
+    public int getPositionForSection(int sectionIndex) {
+        return 0;
+    }
+
+    @Override
+    public int getSectionForPosition(int position) {
+        if (position >= mDataSet.getSize()) {
+            position = mDataSet.getSize() - 1;
+        }
+
+        ColorData color = mDataSet.get(position);
+        return color.getColorGroup().ordinal();
     }
 
 }