一、底层的驱动在这里不提，只关心上层。

二、实现AndroidR 获取接近传感器Proximity Sensor的信号，休眠和唤醒的方法：获取SENSOR_SERVICE服务，侦听Sensor事件。

三、修改的代码，在frameworks\base\services\core\java\com\android\server\policy\PhoneWindowManager.java 文件里面添加下面的代码。

diff --git a/services/core/java/com/android/server/policy/PhoneWindowManager.java b/services/core/java/com/android/server/policy/PhoneWindowManager.java
index d966f36..97b2ef8 100755
--- a/services/core/java/com/android/server/policy/PhoneWindowManager.java
+++ b/services/core/java/com/android/server/policy/PhoneWindowManager.java
@@ -123,6 +123,11 @@ import android.hardware.hdmi.HdmiControlManager;
 import android.hardware.hdmi.HdmiPlaybackClient;
 import android.hardware.hdmi.HdmiPlaybackClient.OneTouchPlayCallback;
 import android.hardware.input.InputManagerInternal;
+import android.hardware.Sensor;
+import android.hardware.SensorEvent;
+import android.hardware.SensorEventListener;
+import android.hardware.SensorManager;
+
 import android.media.AudioAttributes;
 import android.media.AudioManager;
 import android.media.AudioManagerInternal;
@@ -229,6 +234,7 @@ import java.io.IOException;
 import java.io.PrintWriter;
 import java.util.HashSet;
 import java.util.List;
+import android.util.Log;
 
 /**
  * WindowManagerPolicy implementation for the Android phone UI.  This
@@ -378,6 +384,9 @@ public class PhoneWindowManager implements WindowManagerPolicy {
     BurnInProtectionHelper mBurnInProtectionHelper;
     private DisplayFoldController mDisplayFoldController;
     AppOpsManager mAppOpsManager;
+	private Sensor sensor;
+    private SensorManager sm;
+    private SensorEventListener listener;
     PackageManager mPackageManager;
     private boolean mHasFeatureAuto;
     private boolean mHasFeatureWatch;
@@ -1924,6 +1933,37 @@ public class PhoneWindowManager implements WindowManagerPolicy {
                 "PhoneWindowManager.mBroadcastWakeLock");
         mPowerKeyWakeLock = mPowerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK,
                 "PhoneWindowManager.mPowerKeyWakeLock");
+
+        sm=(SensorManager) mContext.getSystemService(Context.SENSOR_SERVICE);
+        sensor=sm.getDefaultSensor(Sensor.TYPE_PROXIMITY);
+
+        listener=new SensorEventListener() {
+
+            @Override
+            public void onSensorChanged(SensorEvent event) {
+                // TODO Auto-generated method stub
+                //获得距离传感器中的数值，这里只有一个距离
+                float[] values = event.values;
+                Log.i(TAG,"onSensorChanged values[0]="+values[0]+" maxrange="+sensor.getMaximumRange());
+
+                if (values[0] == 0.0) {// 贴近手机
+                    mPowerManager.goToSleep(SystemClock.uptimeMillis());
+                    Log.d(TAG, "The object is near to sensor ! go to sleep now");
+                } else {// 远离手机
+				    wakeUpFromPowerKey(SystemClock.uptimeMillis());
+                    Log.d(TAG, "The object is far to sensor !");
+
+                }
+            }
+
+            @Override
+            public void onAccuracyChanged(Sensor sensor, int accuracy) {
+                // TODO Auto-generated method stub
+                Log.i(TAG,"onAccuracyChanged");
+            }
+        };
+
+        sm.registerListener(listener, sensor, SensorManager.SENSOR_DELAY_NORMAL);
         mEnableShiftMenuBugReports = "1".equals(SystemProperties.get("ro.debuggable"));
         mLidKeyboardAccessibility = mContext.getResources().getInteger(
                 com.android.internal.R.integer.config_lidKeyboardAccessibility);

四、用手指接近传感器的时候会灭屏休眠，手指离开的时候亮屏唤醒，查看log如下：