Local UI and byte fixes.

Include local UI to display time. Fix byte casts and
time offset values.

Change-Id: I1f1871a0adbe14666b010fa8e5ce828c6d6be2e2
Signed-off-by: Dave Smith <[email protected]>

Author: Dave Smith

app/src/main/java/com/example/androidthings/gattserver/GattServerActivity.java

@@ -37,16 +37,23 @@
 import android.content.pm.PackageManager;
 import android.os.Bundle;
 import android.os.ParcelUuid;
+import android.text.format.DateFormat;
 import android.util.Log;
+import android.view.WindowManager;
+import android.widget.TextView;
 
 import java.util.Arrays;
+import java.util.Date;
 import java.util.HashSet;
 import java.util.Set;
 
 public class GattServerActivity extends Activity {
     private static final String TAG = GattServerActivity.class.getSimpleName();
 
+    /* Local UI */
+    private TextView mLocalTimeView;
     /* Bluetooth API */
+    private BluetoothManager mBluetoothManager;
     private BluetoothGattServer mBluetoothGattServer;
     private BluetoothLeAdvertiser mBluetoothLeAdvertiser;
     /* Collection of notification subscribers */
@@ -55,10 +62,15 @@ public class GattServerActivity extends Activity {
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_server);
 
-        BluetoothManager manager =
-                (BluetoothManager) getSystemService(BLUETOOTH_SERVICE);
-        BluetoothAdapter bluetoothAdapter = manager.getAdapter();
+        mLocalTimeView = (TextView) findViewById(R.id.text_time);
+
+        // Devices with a display should not go to sleep
+        getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
+
+        mBluetoothManager = (BluetoothManager) getSystemService(BLUETOOTH_SERVICE);
+        BluetoothAdapter bluetoothAdapter = mBluetoothManager.getAdapter();
         // We can't continue without proper Bluetooth support
         if (!checkBluetoothSupport(bluetoothAdapter)) {
             finish();
@@ -72,8 +84,8 @@ protected void onCreate(Bundle savedInstanceState) {
             bluetoothAdapter.enable();
         } else {
             Log.d(TAG, "Bluetooth enabled...starting services");
-            startAdvertising(manager);
-            startServer(manager);
+            startAdvertising();
+            startServer();
         }
     }
 
@@ -98,9 +110,7 @@ protected void onStop() {
     protected void onDestroy() {
         super.onDestroy();
 
-        BluetoothManager manager =
-                (BluetoothManager) getSystemService(BLUETOOTH_SERVICE);
-        BluetoothAdapter bluetoothAdapter = manager.getAdapter();
+        BluetoothAdapter bluetoothAdapter = mBluetoothManager.getAdapter();
         if (bluetoothAdapter.isEnabled()) {
             stopServer();
             stopAdvertising();
@@ -136,7 +146,7 @@ private boolean checkBluetoothSupport(BluetoothAdapter bluetoothAdapter) {
     private BroadcastReceiver mTimeReceiver = new BroadcastReceiver() {
         @Override
         public void onReceive(Context context, Intent intent) {
-            int adjustReason;
+            byte adjustReason;
             switch (intent.getAction()) {
                 case Intent.ACTION_TIME_CHANGED:
                     adjustReason = TimeProfile.ADJUST_MANUAL;
@@ -149,7 +159,9 @@ public void onReceive(Context context, Intent intent) {
                     adjustReason = TimeProfile.ADJUST_NONE;
                     break;
             }
-            notifyRegisteredDevices(adjustReason);
+            long now = System.currentTimeMillis();
+            notifyRegisteredDevices(now, adjustReason);
+            updateLocalUi(now);
         }
     };
 
@@ -162,12 +174,10 @@ public void onReceive(Context context, Intent intent) {
         public void onReceive(Context context, Intent intent) {
             int state = intent.getIntExtra(BluetoothAdapter.EXTRA_STATE, BluetoothAdapter.STATE_OFF);
 
-            BluetoothManager manager =
-                    (BluetoothManager) getSystemService(BLUETOOTH_SERVICE);
             switch (state) {
                 case BluetoothAdapter.STATE_ON:
-                    startAdvertising(manager);
-                    startServer(manager);
+                    startAdvertising();
+                    startServer();
                     break;
                 case BluetoothAdapter.STATE_OFF:
                     stopServer();
@@ -184,8 +194,8 @@ public void onReceive(Context context, Intent intent) {
      * Begin advertising over Bluetooth that this device is connectable
      * and supports the Current Time Service.
      */
-    private void startAdvertising(BluetoothManager bluetoothManager) {
-        BluetoothAdapter bluetoothAdapter = bluetoothManager.getAdapter();
+    private void startAdvertising() {
+        BluetoothAdapter bluetoothAdapter = mBluetoothManager.getAdapter();
         mBluetoothLeAdvertiser = bluetoothAdapter.getBluetoothLeAdvertiser();
         if (mBluetoothLeAdvertiser == null) {
             Log.w(TAG, "Failed to create advertiser");
@@ -222,14 +232,17 @@ private void stopAdvertising() {
      * Initialize the GATT server instance with the services/characteristics
      * from the Time Profile.
      */
-    private void startServer(BluetoothManager bluetoothManager) {
-        mBluetoothGattServer = bluetoothManager.openGattServer(this, mGattServerCallback);
+    private void startServer() {
+        mBluetoothGattServer = mBluetoothManager.openGattServer(this, mGattServerCallback);
         if (mBluetoothGattServer == null) {
             Log.w(TAG, "Unable to create GATT server");
             return;
         }
 
         mBluetoothGattServer.addService(TimeProfile.createTimeService());
+
+        // Initialize the local UI
+        updateLocalUi(System.currentTimeMillis());
     }
 
     /**
@@ -260,12 +273,12 @@ public void onStartFailure(int errorCode) {
      * Send a time service notification to any devices that are subscribed
      * to the characteristic.
      */
-    public void notifyRegisteredDevices(int adjustReason) {
+    private void notifyRegisteredDevices(long timestamp, byte adjustReason) {
         if (mRegisteredDevices.isEmpty()) {
             Log.i(TAG, "No subscribers registered");
             return;
         }
-        byte[] exactTime = TimeProfile.getExactTime(System.currentTimeMillis(), adjustReason);
+        byte[] exactTime = TimeProfile.getExactTime(timestamp, adjustReason);
 
         Log.i(TAG, "Sending update to " + mRegisteredDevices.size() + " subscribers");
         for (BluetoothDevice device : mRegisteredDevices) {
@@ -277,6 +290,17 @@ public void notifyRegisteredDevices(int adjustReason) {
         }
     }
 
+    /**
+     * Update graphical UI on devices that support it with the current time.
+     */
+    private void updateLocalUi(long timestamp) {
+        Date date = new Date(timestamp);
+        String displayDate = DateFormat.getMediumDateFormat(this).format(date)
+                + "\n"
+                + DateFormat.getTimeFormat(this).format(date);
+        mLocalTimeView.setText(displayDate);
+    }
+
     /**
      * Callback to handle incoming requests to the GATT server.
      * All read/write requests for characteristics and descriptors are handled here.
@@ -289,6 +313,8 @@ public void onConnectionStateChange(BluetoothDevice device, int status, int newS
                 Log.i(TAG, "BluetoothDevice CONNECTED: " + device);
             } else if (newState == BluetoothProfile.STATE_DISCONNECTED) {
                 Log.i(TAG, "BluetoothDevice DISCONNECTED: " + device);
+                //Remove device from any active subscriptions
+                mRegisteredDevices.remove(device);
             }
         }
 

app/src/main/java/com/example/androidthings/gattserver/TimeProfile.java

@@ -77,10 +77,10 @@ public static BluetoothGattService createTimeService() {
     }
 
     /**
-     * Return the current time as an Exact Time 256 Field
-     * for the current time characteristic.
+     * Construct the field values for a Current Time characteristic
+     * from the given epoch timestamp and adjustment reason.
      */
-    public static byte[] getExactTime(long timestamp, int adjustReason) {
+    public static byte[] getExactTime(long timestamp, byte adjustReason) {
         Calendar time = Calendar.getInstance();
         time.setTimeInMillis(timestamp);
 
@@ -91,32 +91,32 @@ public static byte[] getExactTime(long timestamp, int adjustReason) {
         field[0] = (byte) (year & 0xFF);
         field[1] = (byte) ((year >> 8) & 0xFF);
         // Month
-        field[2] = (byte) ((time.get(Calendar.MONTH) + 1) & 0xFF);
+        field[2] = (byte) (time.get(Calendar.MONTH) + 1);
         // Day
-        field[3] = (byte) (time.get(Calendar.DATE) & 0xFF);
+        field[3] = (byte) time.get(Calendar.DATE);
         // Hours
-        field[4] = (byte) (time.get(Calendar.HOUR_OF_DAY) & 0xFF);
+        field[4] = (byte) time.get(Calendar.HOUR_OF_DAY);
         // Minutes
-        field[5] = (byte) (time.get(Calendar.MINUTE) & 0xFF);
+        field[5] = (byte) time.get(Calendar.MINUTE);
         // Seconds
-        field[6] = (byte) (time.get(Calendar.SECOND) & 0xFF);
+        field[6] = (byte) time.get(Calendar.SECOND);
         // Day of Week (1-7)
         field[7] = getDayOfWeekCode(time.get(Calendar.DAY_OF_WEEK));
         // Fractions256
-        field[8] = (byte) ((time.get(Calendar.MILLISECOND) / 256) & 0xFF);
+        field[8] = (byte) (time.get(Calendar.MILLISECOND) / 256);
 
-        field[9] = (byte) (adjustReason & 0xFF);
+        field[9] = adjustReason;
 
         return field;
     }
 
     /* Time bucket constants for local time information */
     private static final int FIFTEEN_MINUTE_MILLIS = 900000;
-    private static final int ONE_HOUR_MILLIS = 3600000;
+    private static final int HALF_HOUR_MILLIS = 1800000;
 
     /**
-     * Return the time zone and DST offset fields that make up
-     * the local time information characteristic.
+     * Construct the field values for a Local Time Information characteristic
+     * from the given epoch timestamp.
      */
     public static byte[] getLocalTimeInfo(long timestamp) {
         Calendar time = Calendar.getInstance();
@@ -125,12 +125,12 @@ public static byte[] getLocalTimeInfo(long timestamp) {
         byte[] field = new byte[2];
 
         // Time zone
-        int rawOffset = time.get(Calendar.ZONE_OFFSET) / FIFTEEN_MINUTE_MILLIS; // 15 minute increments
-        field[0] = (byte) rawOffset;
+        int zoneOffset = time.get(Calendar.ZONE_OFFSET) / FIFTEEN_MINUTE_MILLIS; // 15 minute intervals
+        field[0] = (byte) zoneOffset;
 
         // DST Offset
-        rawOffset = time.get(Calendar.DST_OFFSET) / ONE_HOUR_MILLIS;
-        field[1] = getDstOffsetCode(rawOffset);
+        int dstOffset = time.get(Calendar.DST_OFFSET) / HALF_HOUR_MILLIS; // 30 minute intervals
+        field[1] = getDstOffsetCode(dstOffset);
 
         return field;
     }
@@ -178,16 +178,18 @@ private static byte getDayOfWeekCode(int dayOfWeek) {
     private static final byte DST_UNKNOWN = (byte) 0xFF;
 
     /**
-     * Convert a raw DST offset (in hours) to the corresponding
-     * Bluetooth DST offset code.
+     * Convert a raw DST offset (in 30 minute intervals) to the
+     * corresponding Bluetooth DST offset code.
      */
     private static byte getDstOffsetCode(int rawOffset) {
         switch (rawOffset) {
             case 0:
                 return DST_STANDARD;
             case 1:
-                return DST_SINGLE;
+                return DST_HALF;
             case 2:
+                return DST_SINGLE;
+            case 4:
                 return DST_DOUBLE;
             default:
                 return DST_UNKNOWN;

app/src/main/res/layout/activity_server.xml

@@ -0,0 +1,32 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Copyright (C) 2017 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.
+  -->
+<FrameLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent">
+
+    <TextView
+        android:id="@+id/text_time"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_gravity="center"
+        android:gravity="center"
+        android:textSize="56dp"
+        tools:text="01/01/1970\n12:00"/>
+
+</FrameLayout>