Add sample code for EditorInfo#hintLocales.

This CL adds some sample entries so that IME developers can test their
IMEs with various EditorInfo#hintLocales.

Bug: 22859862
Change-Id: Ic0bc98bc4c9cb7b874ca8d54433bde76d05e8e03

samples/ApiDemos/AndroidManifest.xml

@@ -2145,6 +2145,14 @@
             </intent-filter>
         </activity>
 
+        <activity android:name=".inputmethod.HintLocales"
+                  android:label="Views/Input Method/HintLocales">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.SAMPLE_CODE" />
+            </intent-filter>
+        </activity>
+
         <activity android:name=".view.EditTextDemo"
                   android:label="Views/Text/EditText">
             <intent-filter>

samples/ApiDemos/src/com/example/android/apis/inputmethod/HintLocales.java

@@ -0,0 +1,101 @@
+/*
+ * Copyright (C) 2016 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.android.apis.inputmethod;
+
+import android.app.Activity;
+import android.os.Bundle;
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+import android.util.LocaleList;
+import android.widget.EditText;
+import android.widget.LinearLayout;
+import android.widget.TextView;
+
+import static android.widget.LinearLayout.VERTICAL;
+
+/**
+ * Provide some {@link EditText} with specifying
+ * {@link android.view.inputmethod.EditorInfo#hintLocales} so that IME developers can test their
+ * IMEs.
+ */
+public class HintLocales extends Activity {
+
+    /**
+     * Creates a new instance of {@link EditText} that is configured to specify the given
+     * {@link LocaleList} to {@link android.view.inputmethod.EditorInfo#hintLocales} so that
+     * developers can locally test how the current input method behaves for the given hint locales.
+     *
+     * <p><b>Note:</b> {@link android.view.inputmethod.EditorInfo#hintLocales} is just a hint for
+     * the input method. IME developers can decide how to use it.</p>
+     *
+     * @return A new instance of {@link EditText}, which specifies
+     * {@link android.view.inputmethod.EditorInfo#hintLocales} with the given {@link LocaleList}.
+     * @param hintLocales an ordered list of locales to be specified to
+     * {@link android.view.inputmethod.EditorInfo#hintLocales}.
+     * @see android.view.inputmethod.EditorInfo#hintLocales
+     * @see TextView#setImeHintLocales(LocaleList)
+     * @see LocaleList
+     */
+    @NonNull
+    private EditText createEditTextWithImeHintLocales(@Nullable LocaleList hintLocales) {
+        final EditText exitText = new EditText(this);
+        if (hintLocales == null) {
+            exitText.setHint("EditorInfo#hintLocales: (null)");
+        } else {
+            exitText.setHint("EditorInfo#hintLocales: " + hintLocales.toLanguageTags());
+        }
+        // Both null and non-null locale list are supported.
+        exitText.setImeHintLocales(hintLocales);
+        return exitText;
+    }
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+
+        final LinearLayout layout = new LinearLayout(this);
+        layout.setOrientation(VERTICAL);
+
+        // Test EditorInfo#hintLocales = null. This is the default behavior and should be the same
+        // to the behavior in Android M and prior.
+        layout.addView(createEditTextWithImeHintLocales(null));
+
+        // This gives a hint that the application is confident that the user wants to input text
+        // for "en-US" in this text field.  Note that IME developers can decide how to use this
+        // hint.
+        layout.addView(createEditTextWithImeHintLocales(LocaleList.forLanguageTags("en-US")));
+
+        // Likewise, this gives a hint as a list of locales in the order of likelihood.
+        layout.addView(createEditTextWithImeHintLocales(
+                LocaleList.forLanguageTags("en-GB,en-US,en")));
+
+        // Being able to support 3-letter language code correctly is really important.
+        layout.addView(createEditTextWithImeHintLocales(LocaleList.forLanguageTags("fil-ph")));
+
+        // Likewise, test some more locales.
+        layout.addView(createEditTextWithImeHintLocales(LocaleList.forLanguageTags("fr")));
+        layout.addView(createEditTextWithImeHintLocales(LocaleList.forLanguageTags("zh_CN")));
+        layout.addView(createEditTextWithImeHintLocales(LocaleList.forLanguageTags("ja")));
+
+        // Test more complex BCP 47 language tag.  Here the subtag starts with "x-" is a private-use
+        // subtags.
+        layout.addView(createEditTextWithImeHintLocales(
+                LocaleList.forLanguageTags("ryu-Kana-JP-x-android")));
+
+        setContentView(layout);
+    }
+}