enable user to change wifi sleep policy on kalsms settings page for convenience

AndroidManifest.xml

@@ -14,6 +14,7 @@
     <uses-permission android:name="android.permission.WAKE_LOCK" />
     <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
     <uses-permission android:name="android.permission.INTERNET" />
+    <uses-permission android:name="android.permission.WRITE_SETTINGS" />
 
     <application android:name="org.envaya.kalsms.App"
         android:icon="@drawable/icon" android:label="@string/app_name">

README

@@ -1,24 +1,6 @@
 KalSMS is an Android app that acts as a SMS and MMS gateway. 
-For more information, see http://youngj.github.com/KalSMS/
 
-Features
+For more information and installation instructions, 
---------
+see http://youngj.github.com/KalSMS/
-*   Can be deployed almost anywhere in the world
+
-*   Designed to allow non-technical users to do all setup/maintenance 
-    of deployed phones
-*   Can send outgoing SMS in excess of Android's limit of 100 messages 
-    per app per hour by installing expansion packs
-*   Many different phones running KalSMS can be connected to a single server 
-    (each phone could forward messages for a different mobile network)
-*   Authenticates with password shared between phone and server
-*   Retries forwarding messages after a delay if there is an error 
-    (e.g. due to temporarily broken internet or GSM connection)
-*   Notifies the server of the status of outgoing messages
-*   Forwards incoming MMS messages (pictures/video/audio)
-*   Shows log messages to user to facilitate troubleshooting
-*   Can prevent incoming messages from being stored in Messaging inbox
-*   Can forward messages already received in Messaging inbox
-    
-License
--------
 The code is released under the MIT license; see LICENSE

res/values/arrays.xml

@@ -24,4 +24,16 @@
         <item>3600</item>        
         <item>0</item>        
     </string-array>
+    
+    <string-array name="wifi_sleep_policies">        
+        <item>disconnect when screen turns off</item>
+        <item>stay connected when plugged in</item>
+        <item>always stay connected</item>
+    </string-array>
+    
+    <string-array name="wifi_sleep_policies_values">
+        <item>screen</item>
+        <item>plugged</item>
+        <item>never</item>
+    </string-array>    
 </resources>

res/xml/prefs.xml

@@ -18,7 +18,7 @@
 
     <EditTextPreference 
             android:key="phone_number" 
-            android:title="Your Phone Number" 
+            android:title="Your phone number" 
             android:defaultValue=""
     ></EditTextPreference>
 
@@ -43,4 +43,13 @@
             android:summaryOn="Incoming SMS will be stored in Messaging inbox"
     ></CheckBoxPreference>
     
+    <ListPreference
+            android:key="wifi_sleep_policy" 
+            android:title="Wi-Fi sleep policy"
+            android:defaultValue="never"
+            android:entries="@array/wifi_sleep_policies"
+            android:entryValues="@array/wifi_sleep_policies_values"            
+    >           
+    </ListPreference>        
+    
 </PreferenceScreen>

src/org/envaya/kalsms/ui/Prefs.java

@@ -8,6 +8,8 @@ import android.preference.ListPreference;
 import android.preference.Preference;
 import android.preference.PreferenceActivity;
 import android.preference.PreferenceScreen;
+import android.provider.Settings;
+import android.provider.Settings.SettingNotFoundException;
 import android.view.Menu;
 import org.envaya.kalsms.App;
 import org.envaya.kalsms.R;
@@ -50,6 +52,26 @@ public class Prefs extends PreferenceActivity implements OnSharedPreferenceChang
         {            
             app.setOutgoingMessageAlarm();
         }
+        else if (key.equals("wifi_sleep_policy"))
+        {
+            int value;
+            String valueStr = sharedPreferences.getString("wifi_sleep_policy", "screen");
+            if ("screen".equals(valueStr))
+            {
+                value = Settings.System.WIFI_SLEEP_POLICY_DEFAULT;
+            }
+            else if ("plugged".equals(valueStr))
+            {
+                value = Settings.System.WIFI_SLEEP_POLICY_NEVER_WHILE_PLUGGED;
+            }
+            else 
+            {
+                value = Settings.System.WIFI_SLEEP_POLICY_NEVER;
+            }
+            
+            Settings.System.putInt(getContentResolver(), 
+                Settings.System.WIFI_SLEEP_POLICY, value);
+        }
         else if (key.equals("server_url"))
         {
             app.log("Server URL changed to: " + app.getDisplayString(app.getServerUrl()));
@@ -73,7 +95,34 @@ public class Prefs extends PreferenceActivity implements OnSharedPreferenceChang
 
     private void updatePrefSummary(Preference p)
     {
-        if (p instanceof ListPreference) {
+        if ("wifi_sleep_policy".equals(p.getKey()))
+        {       
+            int sleepPolicy;
+            
+            try
+            {
+                sleepPolicy = Settings.System.getInt(this.getContentResolver(), 
+                    Settings.System.WIFI_SLEEP_POLICY);                
+            }
+            catch (SettingNotFoundException ex)
+            {
+                sleepPolicy = Settings.System.WIFI_SLEEP_POLICY_DEFAULT;
+            }               
+            
+            switch (sleepPolicy)
+            {
+                case Settings.System.WIFI_SLEEP_POLICY_DEFAULT:
+                    p.setSummary("Wi-Fi will disconnect when the phone sleeps");
+                    break;
+                case Settings.System.WIFI_SLEEP_POLICY_NEVER_WHILE_PLUGGED:
+                    p.setSummary("Wi-Fi will disconnect when the phone sleeps unless it is plugged in");
+                    break;
+                case Settings.System.WIFI_SLEEP_POLICY_NEVER:
+                    p.setSummary("Wi-Fi will stay connected when the phone sleeps");
+                    break;
+            }
+        }
+        else if (p instanceof ListPreference) {
             p.setSummary(((ListPreference)p).getEntry()); 
         }
         else if (p instanceof EditTextPreference) {