add qrcode for invite to invite-how alert

Need to find the right place for it, explain it, and get rid of the
alert it's part of when the invite is accepted.

xwords4/android/app/build.gradle

@@ -333,6 +333,8 @@ dependencies {
     implementation 'com.github.eehouse:nbsproxy:v0.2.2'
 
     implementation "org.eclipse.paho:org.eclipse.paho.client.mqttv3:1.1.+"
+
+    implementation 'com.google.zxing:core:3.3.+'
 }
 
 task mkImages(type: Exec) {

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

@@ -821,7 +821,8 @@ public class BoardDelegate extends DelegateBase
     private void showInviteChoicesThen( Object[] params )
     {
         SentInvitesInfo info = (SentInvitesInfo)params[0];
-        showInviteChoicesThen( Action.LAUNCH_INVITE_ACTION, info );
+        NetLaunchInfo nli = nliForMe();
+        showInviteChoicesThen( Action.LAUNCH_INVITE_ACTION, info, nli );
     }
 
     @Override

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

@@ -595,9 +595,10 @@ public class DelegateBase implements DlgClickNotify,
     }
 
     protected void showInviteChoicesThen( Action action,
-                                          DBUtils.SentInvitesInfo info )
+                                          DBUtils.SentInvitesInfo info,
+                                          NetLaunchInfo nli)
     {
-        m_dlgDelegate.showInviteChoicesThen( action, info );
+        m_dlgDelegate.showInviteChoicesThen( action, info, nli );
     }
 
     public Builder makeOkOnlyBuilder( int msgID )

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

@@ -394,11 +394,12 @@ public class DlgDelegate {
     }
 
     public void showInviteChoicesThen( final Action action,
-                                       SentInvitesInfo info )
+                                       SentInvitesInfo info,
+                                       NetLaunchInfo nli )
     {
         DlgState state = new DlgState( DlgID.INVITE_CHOICES_THEN )
             .setAction( action )
-            .setParams( info );
+            .setParams( info, nli );
         m_dlgt.show( state );
     }
 

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

@@ -55,12 +55,16 @@ public class InviteChoicesAlert extends DlgDelegateAlert
     {
         ArrayList<InviteMeans> means = new ArrayList<>();
         InviteMeans lastMeans = null;
+        NetLaunchInfo nli = null;
         Object[] params = state.getParams();
-        if ( null != params
-             && params[0] instanceof SentInvitesInfo ) {
-            lastMeans = ((SentInvitesInfo)params[0]).getLastMeans();
+        if ( null != params ) {
+            if ( 0 < params.length && params[0] instanceof SentInvitesInfo ) {
+                lastMeans = ((SentInvitesInfo)params[0]).getLastMeans();
+            }
+            if ( 1 < params.length && params[1] instanceof NetLaunchInfo ) {
+                nli = (NetLaunchInfo)params[1];
+            }
         }
-
         means.add( InviteMeans.EMAIL );
         means.add( InviteMeans.SMS_USER );
 
@@ -129,7 +133,9 @@ public class InviteChoicesAlert extends DlgDelegateAlert
 
         String[] players = XwJNI.kplr_getPlayers();
         inviteView.setChoices( means, lastSelMeans, players )
-            .setCallbacks( this );
+            .setNli( nli )
+            .setCallbacks( this )
+            ;
 
         if ( false && BuildConfig.DEBUG ) {
             OnClickListener ocl = new OnClickListener() {

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

@@ -20,8 +20,11 @@
 package org.eehouse.android.xw4;
 
 import android.content.Context;
+import android.graphics.Bitmap;
+import android.graphics.Color;
 import android.util.AttributeSet;
 import android.view.View;
+import android.widget.ImageView;
 import android.widget.RadioButton;
 import android.widget.RadioGroup;
 import android.widget.ScrollView;
@@ -30,6 +33,11 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
+import com.google.zxing.BarcodeFormat;
+import com.google.zxing.MultiFormatWriter;
+import com.google.zxing.WriterException;
+import com.google.zxing.common.BitMatrix;
+
 import org.eehouse.android.xw4.DlgDelegate.DlgClickNotify.InviteMeans;
 import org.eehouse.android.xw4.jni.CommsAddrRec.CommsConnType;
 import org.eehouse.android.xw4.loc.LocUtils;
@@ -38,6 +46,7 @@ public class InviteView extends ScrollView
     implements RadioGroup.OnCheckedChangeListener {
 
     private static final String TAG = InviteView.class.getSimpleName();
+    private static final int QRCODE_SIZE = 512;
     
     public interface ItemClicked {
         public void meansClicked( InviteMeans means );
@@ -79,7 +88,9 @@ public class InviteView extends ScrollView
             RadioButton button = (RadioButton)LocUtils
                 .inflate( context, R.layout.invite_radio );
             button.setText( LocUtils.getString( context, means.getUserDescID() ) );
-            mGroupHow.addView( button );
+            // -2: place before QR code and its explanatory text
+            int where = mGroupHow.getChildCount() - 2;
+            mGroupHow.addView( button, where );
             mHowMeans.put( button, means );
         }
 
@@ -100,6 +111,14 @@ public class InviteView extends ScrollView
         return this;
     }
 
+    public InviteView setNli( NetLaunchInfo nli )
+    {
+        if ( null != nli ) {
+            startQRCodeThread( nli );
+        }
+        return this;
+    }
+
     public InviteView setCallbacks( ItemClicked procs ) {
         mProcs = procs;
         return this;
@@ -117,7 +136,6 @@ public class InviteView extends ScrollView
                 result = mHowMeans.get(checked);
             }
         }
-        Log.d( TAG, "getChoice() => %s", result );
         return result;
     }
 
@@ -163,4 +181,37 @@ public class InviteView extends ScrollView
         findViewById( R.id.who_empty )
             .setVisibility( showEmpty ? View.VISIBLE : View.INVISIBLE );
     }
+
+    private void startQRCodeThread( NetLaunchInfo nli )
+    {
+        final String url = nli.makeLaunchUri( getContext() ).toString();
+        new Thread( new Runnable() {
+                @Override
+                public void run() {
+                    try {
+                        MultiFormatWriter multiFormatWriter = new MultiFormatWriter();
+                        BitMatrix bitMatrix = multiFormatWriter.encode( url, BarcodeFormat.QR_CODE,
+                                                                        QRCODE_SIZE, QRCODE_SIZE );
+                        final Bitmap bitmap = Bitmap.createBitmap( QRCODE_SIZE, QRCODE_SIZE,
+                                                                   Bitmap.Config.ARGB_8888 );
+                        for ( int ii = 0; ii < QRCODE_SIZE; ++ii ) {
+                            for ( int jj = 0; jj < QRCODE_SIZE; ++jj ) {
+                                bitmap.setPixel( ii, jj, bitMatrix.get(ii, jj)
+                                                 ? Color.BLACK : Color.WHITE );
+                            }
+                        }
+
+                        post( new Runnable() {
+                                @Override
+                                public void run() {
+                                    ImageView iv = (ImageView)findViewById( R.id.qr_view );
+                                    iv.setImageBitmap( bitmap );
+                                }
+                            } );
+                    } catch ( WriterException we ) {
+                        Log.ex( TAG, we );
+                    }
+                }
+            } ).start();
+    }
 }

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

@@ -588,7 +588,7 @@ public class NetLaunchInfo implements Serializable {
         String host = LocUtils.getString( context, R.string.invite_host );
         host = NetUtils.forceHost( host );
         Uri.Builder ub = new Uri.Builder()
-            .scheme( "http" )
+            .scheme( "http" )   // PENDING: should be https soon
             .path( String.format( "//%s%s", host,
                                   LocUtils.getString(context, R.string.invite_prefix) ) );
         appendInt( ub, LANG_KEY, lang );

xwords4/android/app/src/main/res/layout/invite_view.xml

@@ -52,7 +52,21 @@
       <RadioGroup android:id="@+id/group_how"
                   android:layout_width="match_parent"
                   android:layout_height="wrap_content"
-                  />
+                  >
+
+        <!-- RadioButtons will be inserted above this item. -->
+        <TextView android:layout_width="wrap_content"
+                  android:layout_height="wrap_content"
+                  android:text="@string/qrcode_invite_summary"
+                  android:textAppearance="?android:attr/textAppearanceMedium"
+                  android:padding="5dp"
+            />
+        <ImageView android:id="@+id/qr_view"
+                   android:layout_width="wrap_content"
+                   android:layout_height="wrap_content"
+                   android:layout_gravity="center_horizontal"
+                   />
+      </RadioGroup>
       <TextView android:id="@+id/who_empty"
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"

xwords4/android/app/src/main/res/values/strings.xml

@@ -1039,6 +1039,9 @@
     <string name="radio_who">Who?</string>
     <!-- Text shown only when there are not any previous opponents to invite -->
     <string name="invite_who_empty_expl">empty expl</string>
+    <!-- Shown above QR code in the how-to-invite dialog -->
+    <string name="qrcode_invite_summary">Or just have your opponent scan this QRCode</string>
+
     <!-- Radio button in invite choices dialog for list ways to send an invitation -->
     <string name="radio_how">How?</string>
     <!-- Button, on DEBUG builds only, causes invitee players to be robots -->