Fixing TTS Settings crash on rotation caused by using deprecated API.

Test: manual - rotated phone while playing TTS
Fix: 145579714

Change-Id: I7232704c92ba8ec34769cf68afe2278e22532d86

src/com/android/settings/tts/TextToSpeechViewModel.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright 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.tts;
+
+import android.app.Application;
+import android.speech.tts.TextToSpeech;
+import android.util.Pair;
+
+import androidx.lifecycle.AndroidViewModel;
+
+/**
+ * A helper view model to protect the TTS object from being destroyed and
+ * recreated on orientation change.
+*/
+public class TextToSpeechViewModel extends AndroidViewModel {
+    private TextToSpeech mTts;
+
+    // Save the application so we can use it as the TTS context
+    private final Application mApplication;
+
+    public TextToSpeechViewModel(Application application) {
+        super(application);
+
+        mApplication = application;
+    }
+
+    /*
+     * Since the view model now controls the TTS object, we need to handle shutting it down
+     * ourselves.
+     */
+    @Override
+    protected void onCleared() {
+        shutdownTts();
+    }
+
+    protected void shutdownTts() {
+        mTts.shutdown();
+        mTts = null;
+    }
+
+    /*
+     * An accessor method to get the TTS object. Returns a pair of the TTS object and a boolean
+     * indicating whether the TTS object was newly created or not.
+     */
+    protected Pair<TextToSpeech, Boolean> getTtsAndWhetherNew(
+            TextToSpeech.OnInitListener listener) {
+        boolean ttsCreated = false;
+        if (mTts == null) {
+            mTts = new TextToSpeech(this.mApplication, listener);
+            ttsCreated = true;
+        }
+
+        return Pair.create(mTts, ttsCreated);
+    }
+
+}