/*
* Copyright (C) 2008 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 android.view;
import android.content.Context;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.util.Config;
import android.util.Log;
/**
* A special helper class used by the WindowManager
* for receiving notifications from the SensorManager when
* the orientation of the device has changed.
* @hide
*/
public abstract class WindowOrientationListener {
private static final String TAG = "WindowOrientationListener";
private static final boolean DEBUG = false;
private static final boolean localLOGV = DEBUG ? Config.LOGD : Config.LOGV;
private SensorManager mSensorManager;
private boolean mEnabled = false;
private int mRate;
private Sensor mSensor;
private SensorEventListener mSensorEventListener;
private int mSensorRotation = -1;
/**
* Creates a new WindowOrientationListener.
*
* @param context for the WindowOrientationListener.
*/
public WindowOrientationListener(Context context) {
this(context, SensorManager.SENSOR_DELAY_NORMAL);
}
/**
* Creates a new WindowOrientationListener.
*
* @param context for the WindowOrientationListener.
* @param rate at which sensor events are processed (see also
* {@link android.hardware.SensorManager SensorManager}). Use the default
* value of {@link android.hardware.SensorManager#SENSOR_DELAY_NORMAL
* SENSOR_DELAY_NORMAL} for simple screen orientation change detection.
*/
public WindowOrientationListener(Context context, int rate) {
mSensorManager = (SensorManager)context.getSystemService(Context.SENSOR_SERVICE);
mRate = rate;
mSensor = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
if (mSensor != null) {
// Create listener only if sensors do exist
mSensorEventListener = new SensorEventListenerImpl();
}
}
/**
* Enables the WindowOrientationListener so it will monitor the sensor and call
* {@link #onOrientationChanged} when the device orientation changes.
*/
public void enable() {
if (mSensor == null) {
Log.w(TAG, "Cannot detect sensors. Not enabled");
return;
}
if (mEnabled == false) {
if (localLOGV) Log.d(TAG, "WindowOrientationListener enabled");
mSensorRotation = -1;
mSensorManager.registerListener(mSensorEventListener, mSensor, mRate);
mEnabled = true;
}
}
/**
* Disables the WindowOrientationListener.
*/
public void disable() {
if (mSensor == null) {
Log.w(TAG, "Cannot detect sensors. Invalid disable");
return;
}
if (mEnabled == true) {
if (localLOGV) Log.d(TAG, "WindowOrientationListener disabled");
mSensorRotation = -1;
mSensorManager.unregisterListener(mSensorEventListener);
mEnabled = false;
}
}
public int getCurrentRotation() {
return mSensorRotation;
}
class SensorEventListenerImpl implements SensorEventListener {
private static final int _DATA_X = 0;
private static final int _DATA_Y = 1;
private static final int _DATA_Z = 2;
// Angle around x-axis thats considered almost perfect vertical to hold
// the device
private static final int PIVOT = 20;
// Angle around x-asis that's considered almost too vertical. Beyond
// this angle will not result in any orientation changes. f phone faces uses,
// the device is leaning backward.
private static final int PIVOT_UPPER = 65;
// Angle about x-axis that's considered negative vertical. Beyond this
// angle will not result in any orientation changes. If phone faces uses,
// the device is leaning forward.
private static final int PIVOT_LOWER = -10;
// Upper threshold limit for switching from portrait to landscape
private static final int PL_UPPER = 295;
// Lower threshold limit for switching from landscape to portrait
private static final int LP_LOWER = 320;
// Lower threshold limt for switching from portrait to landscape
private static final int PL_LOWER = 270;
// Upper threshold limit for switching from landscape to portrait
private static final int LP_UPPER = 359;
// Minimum angle which is considered landscape
private static final int LANDSCAPE_LOWER = 235;
// Minimum angle which is considered portrait
private static final int PORTRAIT_LOWER = 60;
// Internal value used for calculating linear variant
private static final float PL_LF_UPPER =
((float)(PL_UPPER-PL_LOWER))/((float)(PIVOT_UPPER-PIVOT));
private static final float PL_LF_LOWER =
((float)(PL_UPPER-PL_LOWER))/((float)(PIVOT-PIVOT_LOWER));
// Internal value used for calculating linear variant
private static final float LP_LF_UPPER =
((float)(LP_UPPER - LP_LOWER))/((float)(PIVOT_UPPER-PIVOT));
private static final float LP_LF_LOWER =
((float)(LP_UPPER - LP_LOWER))/((float)(PIVOT-PIVOT_LOWER));
public void onSensorChanged(SensorEvent event) {
float[] values = event.values;
float X = values[_DATA_X];
float Y = values[_DATA_Y];
float Z = values[_DATA_Z];
float OneEightyOverPi = 57.29577957855f;
float gravity = (float) Math.sqrt(X*X+Y*Y+Z*Z);
float zyangle = (float)Math.asin(Z/gravity)*OneEightyOverPi;
int rotation = -1;
if ((zyangle <= PIVOT_UPPER) && (zyangle >= PIVOT_LOWER)) {
// Check orientation only if the phone is flat enough
// Don't trust the angle if the magnitude is small compared to the y value
float angle = (float)Math.atan2(Y, -X) * OneEightyOverPi;
int orientation = 90 - (int)Math.round(angle);
// normalize to 0 - 359 range
while (orientation >= 360) {
orientation -= 360;
}
while (orientation < 0) {
orientation += 360;
}
// Orientation values between LANDSCAPE_LOWER and PL_LOWER
// are considered landscape.
// Ignore orientation values between 0 and LANDSCAPE_LOWER
// For orientation values between LP_UPPER and PL_LOWER,
// the threshold gets set linearly around PIVOT.
if ((orientation >= PL_LOWER) && (orientation <= LP_UPPER)) {
float threshold;
float delta = zyangle - PIVOT;
if (mSensorRotation == Surface.ROTATION_90) {
if (delta < 0) {
// Delta is negative
threshold = LP_LOWER - (LP_LF_LOWER * delta);
} else {
threshold = LP_LOWER + (LP_LF_UPPER * delta);
}
rotation = (orientation >= threshold) ? Surface.ROTATION_0 : Surface.ROTATION_90;
} else {
if (delta < 0) {
// Delta is negative
threshold = PL_UPPER+(PL_LF_LOWER * delta);
} else {
threshold = PL_UPPER-(PL_LF_UPPER * delta);
}
rotation = (orientation <= threshold) ? Surface.ROTATION_90: Surface.ROTATION_0;
}
} else if ((orientation >= LANDSCAPE_LOWER) && (orientation < LP_LOWER)) {
rotation = Surface.ROTATION_90;
} else if ((orientation >= PL_UPPER) || (orientation <= PORTRAIT_LOWER)) {
rotation = Surface.ROTATION_0;
}
if ((rotation != -1) && (rotation != mSensorRotation)) {
mSensorRotation = rotation;
onOrientationChanged(mSensorRotation);
}
}
}
public void onAccuracyChanged(Sensor sensor, int accuracy) {
}
}
/*
* Returns true if sensor is enabled and false otherwise
*/
public boolean canDetectOrientation() {
return mSensor != null;
}
/**
* Called when the rotation view of the device has changed.
* Can be either Surface.ROTATION_90 or Surface.ROTATION_0.
* @param rotation The new orientation of the device.
*
* @see #ORIENTATION_UNKNOWN
*/
abstract public void onOrientationChanged(int rotation);
}