/*
* Copyright (C) 2009 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.phone;
import android.content.Context;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
/**
* This class is used to listen to the accelerometer to monitor the
* orientation of the phone. The client of this class is notified when
* the orientation changes between horizontal and vertical.
*/
public final class AccelerometerListener {
private static final String TAG = "AccelerometerListener";
private static final boolean DEBUG = true;
private static final boolean VDEBUG = false;
private SensorManager mSensorManager;
private Sensor mSensor;
// mOrientation is the orientation value most recently reported to the client.
private int mOrientation;
// mPendingOrientation is the latest orientation computed based on the sensor value.
// This is sent to the client after a rebounce delay, at which point it is copied to
// mOrientation.
private int mPendingOrientation;
private OrientationListener mListener;
// Device orientation
public static final int ORIENTATION_UNKNOWN = 0;
public static final int ORIENTATION_VERTICAL = 1;
public static final int ORIENTATION_HORIZONTAL = 2;
private static final int ORIENTATION_CHANGED = 1234;
private static final int VERTICAL_DEBOUNCE = 100;
private static final int HORIZONTAL_DEBOUNCE = 500;
private static final double VERTICAL_ANGLE = 50.0;
public interface OrientationListener {
public void orientationChanged(int orientation);
}
public AccelerometerListener(Context context, OrientationListener listener) {
mListener = listener;
mSensorManager = (SensorManager)context.getSystemService(Context.SENSOR_SERVICE);
mSensor = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
}
public void enable(boolean enable) {
if (DEBUG) Log.d(TAG, "enable(" + enable + ")");
synchronized (this) {
if (enable) {
mOrientation = ORIENTATION_UNKNOWN;
mPendingOrientation = ORIENTATION_UNKNOWN;
mSensorManager.registerListener(mSensorListener, mSensor,
SensorManager.SENSOR_DELAY_NORMAL);
} else {
mSensorManager.unregisterListener(mSensorListener);
mHandler.removeMessages(ORIENTATION_CHANGED);
}
}
}
private void setOrientation(int orientation) {
synchronized (this) {
if (mPendingOrientation == orientation) {
// Pending orientation has not changed, so do nothing.
return;
}
// Cancel any pending messages.
// We will either start a new timer or cancel alltogether
// if the orientation has not changed.
mHandler.removeMessages(ORIENTATION_CHANGED);
if (mOrientation != orientation) {
// Set timer to send an event if the orientation has changed since its
// previously reported value.
mPendingOrientation = orientation;
Message m = mHandler.obtainMessage(ORIENTATION_CHANGED);
// set delay to our debounce timeout
int delay = (orientation == ORIENTATION_VERTICAL ? VERTICAL_DEBOUNCE
: HORIZONTAL_DEBOUNCE);
mHandler.sendMessageDelayed(m, delay);
} else {
// no message is pending
mPendingOrientation = ORIENTATION_UNKNOWN;
}
}
}
private void onSensorEvent(double x, double y, double z) {
if (VDEBUG) Log.d(TAG, "onSensorEvent(" + x + ", " + y + ", " + z + ")");
// If some values are exactly zero, then likely the sensor is not powered up yet.
// ignore these events to avoid false horizontal positives.
if (x == 0.0 || y == 0.0 || z == 0.0) return;
// magnitude of the acceleration vector projected onto XY plane
double xy = Math.sqrt(x*x + y*y);
// compute the vertical angle
double angle = Math.atan2(xy, z);
// convert to degrees
angle = angle * 180.0 / Math.PI;
int orientation = (angle > VERTICAL_ANGLE ? ORIENTATION_VERTICAL : ORIENTATION_HORIZONTAL);
if (VDEBUG) Log.d(TAG, "angle: " + angle + " orientation: " + orientation);
setOrientation(orientation);
}
SensorEventListener mSensorListener = new SensorEventListener() {
public void onSensorChanged(SensorEvent event) {
onSensorEvent(event.values[0], event.values[1], event.values[2]);
}
public void onAccuracyChanged(Sensor sensor, int accuracy) {
// ignore
}
};
Handler mHandler = new Handler() {
public void handleMessage(Message msg) {
switch (msg.what) {
case ORIENTATION_CHANGED:
synchronized (this) {
mOrientation = mPendingOrientation;
if (DEBUG) {
Log.d(TAG, "orientation: " +
(mOrientation == ORIENTATION_HORIZONTAL ? "horizontal"
: (mOrientation == ORIENTATION_VERTICAL ? "vertical"
: "unknown")));
}
mListener.orientationChanged(mOrientation);
}
break;
}
}
};
}