prevent loading of WiDirService on older android

On 2.3 anyway there's a java.lang.VerifyError trying to load that
class. So wrap the loading in a new class that catches the error and
sets a boolean so subsequent calls don't need it. There are other calls
that could load the class, but they may not be reachable. To be tested.

xwords4/android/app/src/main/java/org/eehouse/android/xw4/ConnViaViewLayout.java

@@ -124,7 +124,7 @@ public class ConnViaViewLayout extends LinearLayout {
             enabled = RelayService.relayEnabled( context );
             break;
         case COMMS_CONN_P2P:
-            enabled = WiDirService.enabled();
+            enabled = WiDirWrapper.enabled();
             break;
         default:
             Assert.fail();

xwords4/android/app/src/main/java/org/eehouse/android/xw4/DlgDelegate.java

@@ -510,7 +510,7 @@ public class DlgDelegate {
         if ( (XWApp.SMS_INVITE_ENABLED && Utils.deviceSupportsSMS( m_activity ))
              || XWPrefs.getNFCToSelfEnabled( m_activity )
              || NFCUtils.nfcAvail( m_activity )[0]
-             || WiDirService.enabled()
+             || WiDirWrapper.enabled()
              || BTService.BTAvailable() ) {
             DlgState state = new DlgState( DlgID.INVITE_CHOICES_THEN )
                 .setAction( action )
@@ -755,7 +755,7 @@ public class DlgDelegate {
             items.add( getString( R.string.invite_choice_relay ) );
             means.add( DlgClickNotify.InviteMeans.RELAY );
         }
-        if ( WiDirService.enabled() ) {
+        if ( WiDirWrapper.enabled() ) {
             items.add( getString( R.string.invite_choice_p2p ) );
             means.add( DlgClickNotify.InviteMeans.WIFIDIRECT );
         }

xwords4/android/app/src/main/java/org/eehouse/android/xw4/WiDirWrapper.java

@@ -0,0 +1,58 @@
+/* -*- compile-command: "find-and-gradle.sh installXw4Debug"; -*- */
+/*
+ * Copyright 2017 by Eric House (xwords@eehouse.org).  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ */
+
+package org.eehouse.android.xw4;
+
+import android.app.Activity;
+import android.content.Context;
+
+// On older Android we can't load the class WiDirService. So do it with
+// try/catch here
+public class WiDirWrapper {
+
+    private static boolean s_working = false;
+
+    public static void init( Context context )
+    {
+        try {
+            WiDirService.init( context );
+            s_working = true;
+        } catch ( java.lang.VerifyError err ) {
+        }
+    }
+
+    public static boolean enabled()
+    {
+        return s_working && WiDirService.enabled();
+    }
+
+    public static void activityResumed( Activity activity )
+    {
+        if ( s_working ) {
+            WiDirService.activityResumed( activity );
+        }
+    }
+
+    public static void activityPaused( Activity activity )
+    {
+        if ( s_working ) {
+            WiDirService.activityPaused( activity );
+        }
+    }
+}

xwords4/android/app/src/main/java/org/eehouse/android/xw4/XWActivity.java

@@ -74,7 +74,7 @@ public class XWActivity extends FragmentActivity implements Delegator {
         }
         m_dlgt.onPause();
         super.onPause();
-        WiDirService.activityPaused( this );
+        WiDirWrapper.activityPaused( this );
     }
 
     @Override
@@ -84,7 +84,7 @@ public class XWActivity extends FragmentActivity implements Delegator {
             DbgUtils.logi( TAG, "onResume(this=%H)", this );
         }
         super.onResume();
-        WiDirService.activityResumed( this );
+        WiDirWrapper.activityResumed( this );
         m_dlgt.onResume();
     }
 

xwords4/android/app/src/main/java/org/eehouse/android/xw4/XWApp.java

@@ -91,7 +91,7 @@ public class XWApp extends Application {
         BTService.startService( this );
         RelayService.startService( this );
         GCMIntentService.init( this );
-        WiDirService.init( this );
+        WiDirWrapper.init( this );
     }
 
     // This is called on emulator only, but good for ensuring no memory leaks

xwords4/android/app/src/main/java/org/eehouse/android/xw4/jni/CommsAddrRec.java

@@ -27,6 +27,7 @@ import junit.framework.Assert;
 
 import org.eehouse.android.xw4.BTService;
 import org.eehouse.android.xw4.WiDirService;
+import org.eehouse.android.xw4.WiDirWrapper;
 import org.eehouse.android.xw4.DbgUtils;
 import org.eehouse.android.xw4.GameUtils;
 import org.eehouse.android.xw4.R;
@@ -123,7 +124,7 @@ public class CommsAddrRec {
             if ( Utils.isGSMPhone( context ) ) {
                 supported.add( CommsConnType.COMMS_CONN_SMS );
             }
-            if ( WiDirService.enabled() ) {
+            if ( WiDirWrapper.enabled() ) {
                 supported.add( CommsConnType.COMMS_CONN_P2P );
             }
             return supported;