Initial checkin of AOSP Messaging app.

b/23110861

Change-Id: I11db999bd10656801e618f78ab2b2ef74136fff1

src/com/android/messaging/ui/mediapicker/AudioLevelSource.java

@@ -0,0 +1,73 @@
+/*
+ * Copyright (C) 2015 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.messaging.ui.mediapicker;
+
+import com.google.common.base.Preconditions;
+
+import javax.annotation.concurrent.ThreadSafe;
+
+/**
+ * Keeps track of the speech level as last observed by the recognition
+ * engine as microphone data flows through it. Can be polled by the UI to
+ * animate its views.
+ */
+@ThreadSafe
+public class AudioLevelSource {
+    private volatile int mSpeechLevel;
+    private volatile Listener mListener;
+
+    public static final int LEVEL_UNKNOWN = -1;
+
+    public interface Listener {
+        void onSpeechLevel(int speechLevel);
+    }
+
+    public void setSpeechLevel(int speechLevel) {
+        Preconditions.checkArgument(speechLevel >= 0 && speechLevel <= 100 ||
+                speechLevel == LEVEL_UNKNOWN);
+        mSpeechLevel = speechLevel;
+        maybeNotify();
+    }
+
+    public int getSpeechLevel() {
+        return mSpeechLevel;
+    }
+
+    public void reset() {
+        setSpeechLevel(LEVEL_UNKNOWN);
+    }
+
+    public boolean isValid() {
+        return mSpeechLevel > 0;
+    }
+
+    private void maybeNotify() {
+        final Listener l = mListener;
+        if (l != null) {
+            l.onSpeechLevel(mSpeechLevel);
+        }
+    }
+
+    public synchronized void setListener(Listener listener) {
+        mListener = listener;
+    }
+
+    public synchronized void clearListener(Listener listener) {
+        if (mListener == listener) {
+            mListener = null;
+        }
+    }
+}