Merge "Create palette preview for color correction."

res/layout/daltonizer_preview.xml

@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Copyright (C) 2020 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
+  -->
+
+<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:id="@+id/preview_viewport"
+    android:layout_width="wrap_content"
+    android:layout_height="wrap_content">
+
+    <com.android.settings.accessibility.PaletteListView
+        android:id="@+id/palette_listView"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:contentDescription="@null" />
+
+</FrameLayout>

res/layout/palette_listview_item.xml

@@ -0,0 +1,31 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Copyright (C) 2020 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
+  -->
+
+<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="wrap_content"
+    android:layout_height="wrap_content">
+
+    <TextView
+        android:id="@+id/item_textview"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:paddingLeft="10dp"
+        android:textSize="20dp"
+        android:maxLength="20"
+        android:singleLine="true"/>
+
+</FrameLayout>

res/values-night/colors.xml

@@ -22,11 +22,21 @@
     <color name="homepage_card_dismissal_background">@*android:color/material_grey_900</color>
     <color name="contextual_card_background">@*android:color/material_grey_900</color>
     <color name="search_bar_background">@*android:color/material_grey_800</color>
-    <!-- Dialog background color -->
+    <!-- Dialog background color. -->
     <color name="dialog_background">@*android:color/material_grey_800</color>
     <color name="notification_importance_selection_bg">@*android:color/material_grey_800</color>
     <color name="notification_importance_button_selected">#AECBFA</color> <!-- material blue 200 -->
     <color name="notification_importance_button_unselected">#5F6368</color>
     <color name="face_intro_outline">?android:attr/colorAccent</color>
+    <!-- Palette list preference colors. -->
+    <color name="palette_list_gradient_background">@android:color/black</color>
+    <color name="palette_list_color_red">@color/palette_list_dark_mode_color_red</color>
+    <color name="palette_list_color_orange">@color/palette_list_dark_mode_color_orange</color>
+    <color name="palette_list_color_yellow">@color/palette_list_dark_mode_color_yellow</color>
+    <color name="palette_list_color_green">@color/palette_list_dark_mode_color_green</color>
+    <color name="palette_list_color_cyan">@color/palette_list_dark_mode_color_cyan</color>
+    <color name="palette_list_color_blue">@color/palette_list_dark_mode_color_blue</color>
+    <color name="palette_list_color_purple">@color/palette_list_dark_mode_color_purple</color>
+    <color name="palette_list_color_pink">@color/palette_list_dark_mode_color_pink</color>
 </resources>
 

res/values/arrays.xml

@@ -23,19 +23,19 @@
          strings. --> <skip />
     <!-- The time zone picker screen has two levels.  The first level allows the user to choose a region. -->
     <string-array name="timezone_filters">
-    <!-- The next level of the time zoner picker should show time zones from the Americas. -->
+        <!-- The next level of the time zoner picker should show time zones from the Americas. -->
         <item>America</item>
-    <!-- The next level of the time zoner picker should show time zones from Europe. -->
+        <!-- The next level of the time zoner picker should show time zones from Europe. -->
         <item>Europe</item>
-    <!-- The next level of the time zoner picker should show time zones from Africa. -->
+        <!-- The next level of the time zoner picker should show time zones from Africa. -->
         <item>Africa</item>
-    <!-- The next level of the time zoner picker should show time zones from Asia. -->
+        <!-- The next level of the time zoner picker should show time zones from Asia. -->
         <item>Asia</item>
-    <!-- The next level of the time zoner picker should show time zones from Australia. -->
+        <!-- The next level of the time zoner picker should show time zones from Australia. -->
         <item>Australia</item>
-    <!-- The next level of the time zoner picker should show time zones from Pacific. -->
+        <!-- The next level of the time zoner picker should show time zones from Pacific. -->
         <item>Pacific</item>
-    <!-- The next level of the time zoner picker should show time zones from ALL regions. -->
+        <!-- The next level of the time zoner picker should show time zones from ALL regions. -->
         <item>All</item>
     </string-array>
 
@@ -274,8 +274,8 @@
         <item>Require all non-trusted certificate statuses</item>
     </string-array>
 
-   <!-- Wi-Fi AP band settings.  Either Auto, 2.4GHz or 5GHz. -->
+    <!-- Wi-Fi AP band settings.  Either Auto, 2.4GHz or 5GHz. -->
-   <!-- Note that adding/removing/moving the items will need wifi settings code change. -->
+    <!-- Note that adding/removing/moving the items will need wifi settings code change. -->
     <string-array translatable="false" name="wifi_ap_band_config_full">
         <item>1</item>
         <item>2</item>
@@ -301,8 +301,8 @@
         <item>@string/wifi_ap_choose_2G</item>
     </string-array>
 
-   <!-- Wi-Fi WPS setup for p2p connections.  -->
+    <!-- Wi-Fi WPS setup for p2p connections.  -->
-   <!-- Note that adding/removing/moving the items will need wifi settings code change. -->
+    <!-- Note that adding/removing/moving the items will need wifi settings code change. -->
     <string-array name="wifi_p2p_wps_setup">
         <!-- Push button based configuration involves pushing a button on two connecting devices [CHAR LIMIT=30]-->
         <item>Push button</item>
@@ -320,7 +320,7 @@
         <item>Unsuccessful</item>
         <item>Available</item>
         <item>Out-of-range</item>
-   </string-array>
+    </string-array>
 
 
     <!-- Bluetooth Settings -->
@@ -410,7 +410,7 @@
     </string-array>
 
     <!-- Wi-Fi IP settings. -->
-   <!-- Note that adding/removing/moving the items will need wifi settings code change. -->
+    <!-- Note that adding/removing/moving the items will need wifi settings code change. -->
     <string-array name="wifi_ip_settings">
         <!-- Use DHCP (Dynamic Host Configuration Protocol) for obtaining IP settings [CHAR LIMIT=25] -->
         <item>DHCP</item>
@@ -1432,15 +1432,15 @@
 
     <!-- WiFi calling mode array -->
     <string-array name="wifi_calling_mode_summaries" translatable="false">
-         <item>@string/wifi_calling_mode_wifi_preferred_summary</item>
+        <item>@string/wifi_calling_mode_wifi_preferred_summary</item>
-         <item>@string/wifi_calling_mode_cellular_preferred_summary</item>
+        <item>@string/wifi_calling_mode_cellular_preferred_summary</item>
-         <item>@string/wifi_calling_mode_wifi_only_summary</item>
+        <item>@string/wifi_calling_mode_wifi_only_summary</item>
     </string-array>
 
     <!-- WiFi calling mode array without wifi only mode -->
     <string-array name="wifi_calling_mode_summaries_without_wifi_only" translatable="false">
-         <item>@string/wifi_calling_mode_wifi_preferred_summary</item>
+        <item>@string/wifi_calling_mode_wifi_preferred_summary</item>
-         <item>@string/wifi_calling_mode_cellular_preferred_summary</item>
+        <item>@string/wifi_calling_mode_cellular_preferred_summary</item>
     </string-array>
 
     <!-- Carrier variant of Enhaced 4G LTE Mode title.  [CHAR LIMIT=NONE] -->
@@ -1469,4 +1469,27 @@
         <item>"com.google.android.googlequicksearchbox"</item>
     </string-array>
 
+    <!-- Array of titles palette list for accessibility. -->
+    <string-array name="setting_palette_colors" translatable="false" >
+        <item>@string/color_red</item>
+        <item>@string/color_orange</item>
+        <item>@string/color_yellow</item>
+        <item>@string/color_green</item>
+        <item>@string/color_cyan</item>
+        <item>@string/color_blue</item>
+        <item>@string/color_purple</item>
+        <item>@string/color_pink</item>
+    </string-array>
+
+    <!-- Values for palette list view preference. -->
+    <array name="setting_palette_data" translatable="false" >
+        <item>@color/palette_list_color_red</item>
+        <item>@color/palette_list_color_orange</item>
+        <item>@color/palette_list_color_yellow</item>
+        <item>@color/palette_list_color_green</item>
+        <item>@color/palette_list_color_cyan</item>
+        <item>@color/palette_list_color_blue</item>
+        <item>@color/palette_list_color_purple</item>
+        <item>@color/palette_list_color_pink</item>
+    </array>
 </resources>

res/values/colors.xml

@@ -148,4 +148,26 @@
     <color name="face_intro_outline">#ffdadce0</color>
 
     <color name="back_gesture_indicator">#4182ef</color>
+
+    <!-- Palette list preference colors. -->
+    <color name="palette_list_gradient_background">@android:color/white</color>
+    <color name="palette_list_color_red">#d93025</color> <!-- Material Red 600 -->
+    <color name="palette_list_color_orange">#e8710a</color> <!-- Material Orange 600 -->
+    <color name="palette_list_color_yellow">#f9ab00</color> <!-- Material Yellow 600 -->
+    <color name="palette_list_color_green">#1e8e3e</color> <!-- Material Green 600 -->
+    <color name="palette_list_color_cyan">#12b5cb</color> <!-- Material Cyan 600 -->
+    <color name="palette_list_color_blue">#1a73e8</color> <!-- Material Blue 600 -->
+    <color name="palette_list_color_purple">#9334e6</color> <!-- Material Purple 600 -->
+    <color name="palette_list_color_pink">#e52592</color> <!-- Material Pink 600 -->
+
+    <!-- Palette list preference dark mode colors. -->
+    <color name="palette_list_dark_mode_color_red">#f28b82</color> <!-- Material Red 300 -->
+    <color name="palette_list_dark_mode_color_orange">#fcad70</color> <!-- Material Orange 300 -->
+    <color name="palette_list_dark_mode_color_yellow">#fdd663</color> <!-- Material Yellow 300 -->
+    <color name="palette_list_dark_mode_color_green">#81c995</color> <!-- Material Green 300 -->
+    <color name="palette_list_dark_mode_color_cyan">#78d9ec</color> <!-- Material Cyan 300 -->
+    <color name="palette_list_dark_mode_color_blue">#8AB4F8</color> <!-- Material Blue 300 -->
+    <color name="palette_list_dark_mode_color_purple">#c58af9</color> <!-- Material Purple 300 -->
+    <color name="palette_list_dark_mode_color_pink">#ff8bcb</color> <!-- Material Pink 300 -->
+
 </resources>

res/values/strings.xml

@@ -7232,6 +7232,8 @@
     <string name="color_orange">Orange</string>
     <!-- Purple label.  [CHAR LIMIT=40] -->
     <string name="color_purple">Purple</string>
+    <!-- Pink label.  [CHAR LIMIT=40] -->
+    <string name="color_pink">Pink</string>
     <!-- Message informing the user that no SIM card is inserted  [CHAR LIMIT=60] -->
     <string name="sim_no_inserted_msg">No SIM cards inserted</string>
     <!-- SIM status title  [CHAR LIMIT=40] -->

res/xml/accessibility_daltonizer_settings.xml

@@ -21,6 +21,13 @@
     android:persistent="false"
     android:title="@string/accessibility_display_daltonizer_preference_title">
 
+    <com.android.settings.accessibility.PaletteListPreference
+        android:key="daltonizer_preview"
+        android:persistent="false"
+        android:selectable="false"
+        android:title="@string/summary_placeholder"
+        settings:searchable="false"/>
+
     <com.android.settingslib.widget.RadioButtonPreference
         android:key="daltonizer_mode_deuteranomaly"
         android:persistent="false"

src/com/android/settings/accessibility/PaletteListPreference.java

@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2020 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.android.settings.accessibility;
+
+import android.content.Context;
+import android.util.AttributeSet;
+import android.view.View;
+import android.view.ViewTreeObserver;
+import android.widget.FrameLayout;
+import android.widget.ListView;
+
+import androidx.preference.Preference;
+import androidx.preference.PreferenceViewHolder;
+
+import com.android.settingslib.widget.R;
+
+/** Preference that easier preview by matching name to color. */
+public class PaletteListPreference extends Preference {
+
+    /**
+     * Constructs a new PaletteListPreference with the given context's theme and the supplied
+     * attribute set.
+     *
+     * @param context The Context this is associated with, through which it can access the current
+     *                theme, resources, etc.
+     * @param attrs The attributes of the XML tag that is inflating the view.
+     */
+    public PaletteListPreference(Context context, AttributeSet attrs) {
+        this(context, attrs, 0);
+    }
+
+    /**
+     * Constructs a new PaletteListPreference with the given context's theme, the supplied
+     * attribute set, and default style attribute.
+     *
+     * @param context The Context this is associated with, through which it can access the
+     *                current theme, resources, etc.
+     * @param attrs The attributes of the XML tag that is inflating the view.
+     * @param defStyleAttr An attribute in the current theme that contains a reference to a style
+     *                     resource that supplies default
+     *                     values for the view. Can be 0 to not look for
+     *                     defaults.
+     */
+    public PaletteListPreference(Context context, AttributeSet attrs, int defStyleAttr) {
+        super(context, attrs, defStyleAttr);
+        setLayoutResource(R.layout.daltonizer_preview);
+    }
+
+    @Override
+    public void onBindViewHolder(PreferenceViewHolder holder) {
+        super.onBindViewHolder(holder);
+
+        final View rootView = holder.itemView;
+        final ListView listView = rootView.findViewById(R.id.palette_listView);
+        listView.getViewTreeObserver().addOnGlobalLayoutListener(
+                new ViewTreeObserver.OnGlobalLayoutListener() {
+                    @Override
+                    public void onGlobalLayout() {
+                        final int listViewHeight = listView.getMeasuredHeight();
+                        final int listViewWidth = listView.getMeasuredWidth();
+                        // Removes the callback after get result of measure view.
+                        listView.getViewTreeObserver().removeOnGlobalLayoutListener(this);
+
+                        // Resets layout parameters to display whole items from listView.
+                        final FrameLayout.LayoutParams layoutParams =
+                                (FrameLayout.LayoutParams) listView.getLayoutParams();
+                        layoutParams.height = listViewHeight * listView.getAdapter().getCount();
+                        layoutParams.width = listViewWidth;
+                        listView.setLayoutParams(layoutParams);
+                        listView.invalidateViews();
+                    }
+                });
+    }
+}

src/com/android/settings/accessibility/PaletteListView.java

@@ -0,0 +1,292 @@
+/*
+ * Copyright (C) 2020 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.android.settings.accessibility;
+
+import android.annotation.NonNull;
+import android.content.Context;
+import android.content.res.TypedArray;
+import android.graphics.Color;
+import android.graphics.drawable.GradientDrawable;
+import android.graphics.drawable.GradientDrawable.Orientation;
+import android.util.AttributeSet;
+import android.util.DisplayMetrics;
+import android.view.Display;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.view.WindowManager;
+import android.widget.BaseAdapter;
+import android.widget.ListView;
+import android.widget.TextView;
+
+import androidx.annotation.VisibleForTesting;
+
+import com.android.settingslib.widget.R;
+
+import com.google.common.collect.Iterables;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+
+/**
+ * Custom ListView {@link ListView} which displays palette to deploy the color code preview.
+ *
+ * <p>The preview shows gradient from color white to specific color code on each list view item, in
+ * addition, text view adjusts the attribute of width for adapting the text length.
+ *
+ * <p>The text cannot fills the whole view for ensuring the gradient color preview can purely
+ * display also the view background shows the color beside the text variable end point.
+ */
+public class PaletteListView extends ListView {
+    private static final float VIEW_PITCH = 0.05f;
+    private final Context mContext;
+    private final DisplayAdapter mDisplayAdapter;
+    private final LayoutInflater mLayoutInflater;
+    private final String mDefaultGradientColorCodeString;
+    private final int mDefaultGradientColor;
+    private float mTextBound;
+
+    public PaletteListView(Context context) {
+        this(context, null);
+    }
+
+    public PaletteListView(Context context, AttributeSet attrs) {
+        this(context, attrs, 0);
+    }
+
+    public PaletteListView(Context context, AttributeSet attrs, int defStyleAttr) {
+        super(context, attrs, defStyleAttr);
+        mContext = context;
+        mDisplayAdapter = new DisplayAdapter();
+        mLayoutInflater = LayoutInflater.from(context);
+        mDefaultGradientColorCodeString =
+                getResources().getString(R.color.palette_list_gradient_background);
+        mDefaultGradientColor =
+                getResources().getColor(R.color.palette_list_gradient_background, null);
+        mTextBound = 0.0f;
+        init();
+    }
+
+    private static int getScreenWidth(WindowManager windowManager) {
+        final Display display = windowManager.getDefaultDisplay();
+        final DisplayMetrics displayMetrics = new DisplayMetrics();
+        display.getMetrics(displayMetrics);
+        return displayMetrics.widthPixels;
+    }
+
+    private void init() {
+        final TypedArray colorNameArray = getResources().obtainTypedArray(
+                R.array.setting_palette_colors);
+        final TypedArray colorCodeArray = getResources().obtainTypedArray(
+                R.array.setting_palette_data);
+        final int colorNameArrayLength = colorNameArray.length();
+        final List<ColorAttributes> colorList = new ArrayList<>();
+        computeTextWidthBounds(colorNameArray);
+
+        for (int index = 0; index < colorNameArrayLength; index++) {
+            colorList.add(
+                    new ColorAttributes(
+                            /* colorName= */ colorNameArray.getString(index),
+                            /* colorCode= */ colorCodeArray.getColor(index, mDefaultGradientColor),
+                            /* textBound= */ mTextBound,
+                            /* gradientDrawable= */
+                            new GradientDrawable(Orientation.LEFT_RIGHT, null)));
+        }
+
+        mDisplayAdapter.setColorList(colorList);
+        setAdapter(mDisplayAdapter);
+        setDividerHeight(/* height= */ 0);
+    }
+
+    /**
+     * Sets string array that required the color name and color code for deploy the new color
+     * preview.
+     *
+     * <p>The parameters not allow null define but two array length inconsistent are acceptable, in
+     * addition, to prevent IndexOutOfBoundsException the algorithm will check array data, and base
+     * on the array size to display data, or fills color code array if length less than other.
+     *
+     * @param colorNames a string array of color name
+     * @param colorCodes a string array of color code
+     * @return true if new array data apply successful
+     */
+    @VisibleForTesting
+    boolean setPaletteListColors(@NonNull String[] colorNames, @NonNull String[] colorCodes) {
+        if (colorNames == null || colorCodes == null) {
+            return false;
+        }
+
+        final int colorNameArrayLength = colorNames.length;
+        final int colorCodeArrayLength = colorCodes.length;
+        final List<ColorAttributes> colorList = new ArrayList<>();
+        final String[] colorCodeArray = fillColorCodeArray(colorCodes, colorNameArrayLength,
+                colorCodeArrayLength);
+        computeTextWidthBounds(colorNames);
+
+        for (int index = 0; index < colorNameArrayLength; index++) {
+            colorList.add(
+                    new ColorAttributes(
+                            /* colorName= */ colorNames[index],
+                            /* colorCode= */ Color.parseColor(colorCodeArray[index]),
+                            /* textBound= */ mTextBound,
+                            /* gradientDrawable= */
+                            new GradientDrawable(Orientation.LEFT_RIGHT, null)));
+        }
+
+        mDisplayAdapter.setColorList(colorList);
+        mDisplayAdapter.notifyDataSetChanged();
+        return true;
+    }
+
+    private String[] fillColorCodeArray(String[] colorCodes, int colorNameArrayLength,
+            int colorCodeArrayLength) {
+        if (colorNameArrayLength == colorCodeArrayLength
+                || colorNameArrayLength < colorCodeArrayLength) {
+            return colorCodes;
+        }
+
+        final String[] colorCodeArray = new String[colorNameArrayLength];
+        for (int index = 0; index < colorNameArrayLength; index++) {
+            if (index < colorCodeArrayLength) {
+                colorCodeArray[index] = colorCodes[index];
+            } else {
+                colorCodeArray[index] = mDefaultGradientColorCodeString;
+            }
+        }
+        return colorCodeArray;
+    }
+
+    private void computeTextWidthBounds(TypedArray colorNameTypedArray) {
+        final int colorNameArrayLength = colorNameTypedArray.length();
+        final String[] colorNames = new String[colorNameArrayLength];
+        for (int index = 0; index < colorNameArrayLength; index++) {
+            colorNames[index] = colorNameTypedArray.getString(index);
+        }
+
+        measureBound(colorNames);
+    }
+
+    private void computeTextWidthBounds(String[] colorNameArray) {
+        final int colorNameArrayLength = colorNameArray.length;
+        final String[] colorNames = new String[colorNameArrayLength];
+        for (int index = 0; index < colorNameArrayLength; index++) {
+            colorNames[index] = colorNameArray[index];
+        }
+
+        measureBound(colorNames);
+    }
+
+    private void measureBound(String[] dataArray) {
+        final WindowManager windowManager = (WindowManager) mContext.getSystemService(
+                Context.WINDOW_SERVICE);
+        final View view = mLayoutInflater.inflate(R.layout.palette_listview_item, null);
+        final TextView textView = view.findViewById(R.id.item_textview);
+        final List<String> colorNameList = new ArrayList<>(Arrays.asList(dataArray));
+        Collections.sort(colorNameList, Comparator.comparing(String::length));
+        // Gets the last index of list which sort by text length.
+        textView.setText(Iterables.getLast(colorNameList));
+
+        final float textWidth = textView.getPaint().measureText(textView.getText().toString());
+        // Computes rate of text width compare to screen width, and measures the round the double
+        // to two decimal places manually.
+        final float textBound = Math.round(textWidth / getScreenWidth(windowManager) * 100) / 100f;
+        mTextBound = textBound + VIEW_PITCH;
+    }
+
+    private static class ViewHolder {
+        public TextView textView;
+    }
+
+    /** An adapter that converts color text title and color code to text views. */
+    private final class DisplayAdapter extends BaseAdapter {
+
+        private List<ColorAttributes> mColorList;
+
+        @Override
+        public int getCount() {
+            return mColorList.size();
+        }
+
+        @Override
+        public Object getItem(int position) {
+            return mColorList.get(position);
+        }
+
+        @Override
+        public long getItemId(int position) {
+            return position;
+        }
+
+        @Override
+        public View getView(int position, View convertView, ViewGroup parent) {
+            final ViewHolder viewHolder;
+            final ColorAttributes paletteAttribute = mColorList.get(position);
+            final String colorName = paletteAttribute.getColorName();
+            final GradientDrawable gradientDrawable = paletteAttribute.getGradientDrawable();
+
+            if (convertView == null) {
+                convertView = mLayoutInflater.inflate(R.layout.palette_listview_item, null);
+                viewHolder = new ViewHolder();
+                viewHolder.textView = convertView.findViewById(R.id.item_textview);
+                convertView.setTag(viewHolder);
+            } else {
+                viewHolder = (ViewHolder) convertView.getTag();
+            }
+
+            viewHolder.textView.setText(colorName);
+            viewHolder.textView.setBackground(gradientDrawable);
+            return convertView;
+        }
+
+        protected void setColorList(List<ColorAttributes> colorList) {
+            mColorList = colorList;
+        }
+    }
+
+    private final class ColorAttributes {
+        private final int mColorIndex = 2; // index for inject color.
+        private final int mColorOffsetIndex = 1; // index for offset effect.
+        private final String mColorName;
+        private final GradientDrawable mGradientDrawable;
+        private final int[] mGradientColors =
+                {/* startColor=*/ mDefaultGradientColor, /* centerColor=*/ mDefaultGradientColor,
+                        /* endCode= */ 0};
+        private final float[] mGradientOffsets =
+                {/* starOffset= */ 0.0f, /* centerOffset= */ 0.5f, /* endOffset= */ 1.0f};
+
+        ColorAttributes(
+                String colorName, int colorCode, float textBound,
+                GradientDrawable gradientDrawable) {
+            mGradientColors[mColorIndex] = colorCode;
+            mGradientOffsets[mColorOffsetIndex] = textBound;
+            gradientDrawable.setColors(mGradientColors, mGradientOffsets);
+            mColorName = colorName;
+            mGradientDrawable = gradientDrawable;
+        }
+
+        public String getColorName() {
+            return mColorName;
+        }
+
+        public GradientDrawable getGradientDrawable() {
+            return mGradientDrawable;
+        }
+    }
+}

tests/robotests/src/com/android/settings/accessibility/PaletteListViewTest.java

@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2020 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.android.settings.accessibility;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import android.content.Context;
+
+import androidx.test.core.app.ApplicationProvider;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+
+/** Tests for {@link PaletteListView} */
+@RunWith(RobolectricTestRunner.class)
+public class PaletteListViewTest {
+
+    private final Context mContext = ApplicationProvider.getApplicationContext();
+    private PaletteListView mPaletteListView;
+
+    @Before
+    public void setUp() {
+        mPaletteListView = new PaletteListView(mContext);
+    }
+
+    @Test
+    public void setColors_applySameLengthArray_configureSuccessful() {
+        final String[] colorName = {"White", "Black", "Yellow"};
+        final String[] colorCode = {"#ffffff", "#000000", "#f9ab00"};
+
+        assertThat(mPaletteListView.setPaletteListColors(colorName, colorCode)).isTrue();
+    }
+
+    @Test
+    public void setColors_applyDifferentLengthArray_configureSuccessful() {
+        final String[] colorName = {"White", "Black", "Yellow", "Orange", "Red"};
+        final String[] colorCode = {"#ffffff", "#000000", "#f9ab00"};
+
+        assertThat(mPaletteListView.setPaletteListColors(colorName, colorCode)).isTrue();
+    }
+
+    @Test
+    public void setColors_configureFailed() {
+        final String[] colorName = null;
+        final String[] colorCode = null;
+
+        assertThat(mPaletteListView.setPaletteListColors(colorName, colorCode)).isFalse();
+    }
+}