src/com/android/contacts/ProximitySensorManager.java - platform/packages/apps/Contacts - Git at Google

 /*
  * Copyright (C) 2011 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.contacts;

 import android.content.Context;
 import android.hardware.Sensor;
 import android.hardware.SensorEvent;
 import android.hardware.SensorEventListener;
 import android.hardware.SensorManager;

 import javax.annotation.concurrent.GuardedBy;

 /**
  * Manages the proximity sensor and notifies a listener when enabled.
  */
 public class ProximitySensorManager {
     /**
      * Listener of the state of the proximity sensor.
      * <p>
      * This interface abstracts two possible states for the proximity sensor, near and far.
      * <p>
      * The actual meaning of these states depends on the actual sensor.
      */
     public interface Listener {
         /** Called when the proximity sensor transitions from the far to the near state. */
         public void onNear();
         /** Called when the proximity sensor transitions from the near to the far state. */
         public void onFar();
     }

     public static enum State {
         NEAR, FAR
     }

     private final ProximitySensorEventListener mProximitySensorListener;

     /**
      * The current state of the manager, i.e., whether it is currently tracking the state of the
      * sensor.
      */
     private boolean mManagerEnabled;

     /**
      * The listener to the state of the sensor.
      * <p>
      * Contains most of the logic concerning tracking of the sensor.
      * <p>
      * After creating an instance of this object, one should call {@link #register()} and
      * {@link #unregister()} to enable and disable the notifications.
      * <p>
      * Instead of calling unregister, one can call {@link #unregisterWhenFar()} to unregister the
      * listener the next time the sensor reaches the {@link State#FAR} state if currently in the
      * {@link State#NEAR} state.
      */
     private static class ProximitySensorEventListener implements SensorEventListener {
         private static final float FAR_THRESHOLD = 5.0f;

         private final SensorManager mSensorManager;
         private final Sensor mProximitySensor;
         private final float mMaxValue;
         private final Listener mListener;

         /**
          * The last state of the sensor.
          * <p>
          * Before registering and after unregistering we are always in the {@link State#FAR} state.
          */
         @GuardedBy("this") private State mLastState;
         /**
          * If this flag is set to true, we are waiting to reach the {@link State#FAR} state and
          * should notify the listener and unregister when that happens.
          */
         @GuardedBy("this") private boolean mWaitingForFarState;

         public ProximitySensorEventListener(SensorManager sensorManager, Sensor proximitySensor,
                 Listener listener) {
             mSensorManager = sensorManager;
             mProximitySensor = proximitySensor;
             mMaxValue = proximitySensor.getMaximumRange();
             mListener = listener;
             // Initialize at far state.
             mLastState = State.FAR;
             mWaitingForFarState = false;
         }

         @Override
         public void onSensorChanged(SensorEvent event) {
             // Make sure we have a valid value.
             if (event.values == null) return;
             if (event.values.length == 0) return;
             float value = event.values[0];
             // Convert the sensor into a NEAR/FAR state.
             State state = getStateFromValue(value);
             synchronized (this) {
                 // No change in state, do nothing.
                 if (state == mLastState) return;
                 // Keep track of the current state.
                 mLastState = state;
                 // If we are waiting to reach the far state and we are now in it, unregister.
                 if (mWaitingForFarState && mLastState == State.FAR) {
                     unregisterWithoutNotification();
                 }
             }
             // Notify the listener of the state change.
             switch (state) {
                 case NEAR:
                     mListener.onNear();
                     break;

                 case FAR:
                     mListener.onFar();
                     break;
             }
         }

         @Override
         public void onAccuracyChanged(Sensor sensor, int accuracy) {
             // Nothing to do here.
         }

         /** Returns the state of the sensor given its current value. */
         private State getStateFromValue(float value) {
             // Determine if the current value corresponds to the NEAR or FAR state.
             // Take case of the case where the proximity sensor is binary: if the current value is
             // equal to the maximum, we are always in the FAR state.
             return (value > FAR_THRESHOLD || value == mMaxValue) ? State.FAR : State.NEAR;
         }

         /**
          * Unregister the next time the sensor reaches the {@link State#FAR} state.
          */
         public synchronized void unregisterWhenFar() {
             if (mLastState == State.FAR) {
                 // We are already in the far state, just unregister now.
                 unregisterWithoutNotification();
             } else {
                 mWaitingForFarState = true;
             }
         }

         /** Register the listener and call the listener as necessary. */
         public synchronized void register() {
             // It is okay to register multiple times.
             mSensorManager.registerListener(this, mProximitySensor, SensorManager.SENSOR_DELAY_UI);
             // We should no longer be waiting for the far state if we are registering again.
             mWaitingForFarState = false;
         }

         public void unregister() {
             State lastState;
             synchronized (this) {
                 unregisterWithoutNotification();
                 lastState = mLastState;
                 // Always go back to the FAR state. That way, when we register again we will get a
                 // transition when the sensor gets into the NEAR state.
                 mLastState = State.FAR;
             }
             // Notify the listener if we changed the state to FAR while unregistering.
             if (lastState != State.FAR) {
                 mListener.onFar();
             }
         }

         @GuardedBy("this")
         private void unregisterWithoutNotification() {
             mSensorManager.unregisterListener(this);
             mWaitingForFarState = false;
         }
     }

     public ProximitySensorManager(Context context, Listener listener) {
         SensorManager sensorManager =
                 (SensorManager) context.getSystemService(Context.SENSOR_SERVICE);
         Sensor proximitySensor = sensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY);
         if (proximitySensor == null) {
             // If there is no sensor, we should not do anything.
             mProximitySensorListener = null;
         } else {
             mProximitySensorListener =
                     new ProximitySensorEventListener(sensorManager, proximitySensor, listener);
         }
     }

     /**
      * Enables the proximity manager.
      * <p>
      * The listener will start getting notifications of events.
      * <p>
      * This method is idempotent.
      */
     public void enable() {
         if (mProximitySensorListener != null && !mManagerEnabled) {
             mProximitySensorListener.register();
             mManagerEnabled = true;
         }
     }

     /**
      * Disables the proximity manager.
      * <p>
      * The listener will stop receiving notifications of events, possibly after receiving a last
      * {@link Listener#onFar()} callback.
      * <p>
      * If {@code waitForFarState} is true, if the sensor is not currently in the {@link State#FAR}
      * state, the listener will receive a {@link Listener#onFar()} callback the next time the sensor
      * actually reaches the {@link State#FAR} state.
      * <p>
      * If {@code waitForFarState} is false, the listener will receive a {@link Listener#onFar()}
      * callback immediately if the sensor is currently not in the {@link State#FAR} state.
      * <p>
      * This method is idempotent.
      */
     public void disable(boolean waitForFarState) {
         if (mProximitySensorListener != null && mManagerEnabled) {
             if (waitForFarState) {
                 mProximitySensorListener.unregisterWhenFar();
             } else {
                 mProximitySensorListener.unregister();
             }
             mManagerEnabled = false;
         }
     }
 }
	/*
	* Copyright (C) 2011 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.contacts;

	import android.content.Context;
	import android.hardware.Sensor;
	import android.hardware.SensorEvent;
	import android.hardware.SensorEventListener;
	import android.hardware.SensorManager;

	import javax.annotation.concurrent.GuardedBy;

	/**
	* Manages the proximity sensor and notifies a listener when enabled.
	*/
	public class ProximitySensorManager {
	/**
	* Listener of the state of the proximity sensor.
	* <p>
	* This interface abstracts two possible states for the proximity sensor, near and far.
	* <p>
	* The actual meaning of these states depends on the actual sensor.
	*/
	public interface Listener {
	/** Called when the proximity sensor transitions from the far to the near state. */
	public void onNear();
	/** Called when the proximity sensor transitions from the near to the far state. */
	public void onFar();
	}

	public static enum State {
	NEAR, FAR
	}

	private final ProximitySensorEventListener mProximitySensorListener;

	/**
	* The current state of the manager, i.e., whether it is currently tracking the state of the
	* sensor.
	*/
	private boolean mManagerEnabled;

	/**
	* The listener to the state of the sensor.
	* <p>
	* Contains most of the logic concerning tracking of the sensor.
	* <p>
	* After creating an instance of this object, one should call {@link #register()} and
	* {@link #unregister()} to enable and disable the notifications.
	* <p>
	* Instead of calling unregister, one can call {@link #unregisterWhenFar()} to unregister the
	* listener the next time the sensor reaches the {@link State#FAR} state if currently in the
	* {@link State#NEAR} state.
	*/
	private static class ProximitySensorEventListener implements SensorEventListener {
	private static final float FAR_THRESHOLD = 5.0f;

	private final SensorManager mSensorManager;
	private final Sensor mProximitySensor;
	private final float mMaxValue;
	private final Listener mListener;

	/**
	* The last state of the sensor.
	* <p>
	* Before registering and after unregistering we are always in the {@link State#FAR} state.
	*/
	@GuardedBy("this") private State mLastState;
	/**
	* If this flag is set to true, we are waiting to reach the {@link State#FAR} state and
	* should notify the listener and unregister when that happens.
	*/
	@GuardedBy("this") private boolean mWaitingForFarState;

	public ProximitySensorEventListener(SensorManager sensorManager, Sensor proximitySensor,
	Listener listener) {
	mSensorManager = sensorManager;
	mProximitySensor = proximitySensor;
	mMaxValue = proximitySensor.getMaximumRange();
	mListener = listener;
	// Initialize at far state.
	mLastState = State.FAR;
	mWaitingForFarState = false;
	}

	@Override
	public void onSensorChanged(SensorEvent event) {
	// Make sure we have a valid value.
	if (event.values == null) return;
	if (event.values.length == 0) return;
	float value = event.values[0];
	// Convert the sensor into a NEAR/FAR state.
	State state = getStateFromValue(value);
	synchronized (this) {
	// No change in state, do nothing.
	if (state == mLastState) return;
	// Keep track of the current state.
	mLastState = state;
	// If we are waiting to reach the far state and we are now in it, unregister.
	if (mWaitingForFarState && mLastState == State.FAR) {
	unregisterWithoutNotification();
	}
	}
	// Notify the listener of the state change.
	switch (state) {
	case NEAR:
	mListener.onNear();
	break;

	case FAR:
	mListener.onFar();
	break;
	}
	}

	@Override
	public void onAccuracyChanged(Sensor sensor, int accuracy) {
	// Nothing to do here.
	}

	/** Returns the state of the sensor given its current value. */
	private State getStateFromValue(float value) {
	// Determine if the current value corresponds to the NEAR or FAR state.
	// Take case of the case where the proximity sensor is binary: if the current value is
	// equal to the maximum, we are always in the FAR state.
	return (value > FAR_THRESHOLD \|\| value == mMaxValue) ? State.FAR : State.NEAR;
	}

	/**
	* Unregister the next time the sensor reaches the {@link State#FAR} state.
	*/
	public synchronized void unregisterWhenFar() {
	if (mLastState == State.FAR) {
	// We are already in the far state, just unregister now.
	unregisterWithoutNotification();
	} else {
	mWaitingForFarState = true;
	}
	}

	/** Register the listener and call the listener as necessary. */
	public synchronized void register() {
	// It is okay to register multiple times.
	mSensorManager.registerListener(this, mProximitySensor, SensorManager.SENSOR_DELAY_UI);
	// We should no longer be waiting for the far state if we are registering again.
	mWaitingForFarState = false;
	}

	public void unregister() {
	State lastState;
	synchronized (this) {
	unregisterWithoutNotification();
	lastState = mLastState;
	// Always go back to the FAR state. That way, when we register again we will get a
	// transition when the sensor gets into the NEAR state.
	mLastState = State.FAR;
	}
	// Notify the listener if we changed the state to FAR while unregistering.
	if (lastState != State.FAR) {
	mListener.onFar();
	}
	}

	@GuardedBy("this")
	private void unregisterWithoutNotification() {
	mSensorManager.unregisterListener(this);
	mWaitingForFarState = false;
	}
	}

	public ProximitySensorManager(Context context, Listener listener) {
	SensorManager sensorManager =
	(SensorManager) context.getSystemService(Context.SENSOR_SERVICE);
	Sensor proximitySensor = sensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY);
	if (proximitySensor == null) {
	// If there is no sensor, we should not do anything.
	mProximitySensorListener = null;
	} else {
	mProximitySensorListener =
	new ProximitySensorEventListener(sensorManager, proximitySensor, listener);
	}
	}

	/**
	* Enables the proximity manager.
	* <p>
	* The listener will start getting notifications of events.
	* <p>
	* This method is idempotent.
	*/
	public void enable() {
	if (mProximitySensorListener != null && !mManagerEnabled) {
	mProximitySensorListener.register();
	mManagerEnabled = true;
	}
	}

	/**
	* Disables the proximity manager.
	* <p>
	* The listener will stop receiving notifications of events, possibly after receiving a last
	* {@link Listener#onFar()} callback.
	* <p>
	* If {@code waitForFarState} is true, if the sensor is not currently in the {@link State#FAR}
	* state, the listener will receive a {@link Listener#onFar()} callback the next time the sensor
	* actually reaches the {@link State#FAR} state.
	* <p>
	* If {@code waitForFarState} is false, the listener will receive a {@link Listener#onFar()}
	* callback immediately if the sensor is currently not in the {@link State#FAR} state.
	* <p>
	* This method is idempotent.
	*/
	public void disable(boolean waitForFarState) {
	if (mProximitySensorListener != null && mManagerEnabled) {
	if (waitForFarState) {
	mProximitySensorListener.unregisterWhenFar();
	} else {
	mProximitySensorListener.unregister();
	}
	mManagerEnabled = false;
	}
	}
	}