Show message when touching the QRCode button, but swap isn't enabled.

Also cleaned up a doc comment in the swap activity, and minor
formatting of swap related strings in strings.xml.

F-Droid/res/values/strings.xml

@@ -372,6 +372,8 @@
     <string name="loading">Loading…</string>
     <string name="swap_attempt_install">TRY TO INSTALL</string>
     <string name="swap_connection_misc_error">An error occurred while connecting to device, we can\'t seem to swap with it :(</string>
+    <string name="swap_not_enabled">Swapping not enabled</string>
+    <string name="swap_not_enabled_description">Before swapping, your device must be made visible.</string>
 
     <string name="install_confirm">Do you want to install this application?
             It will get access to:</string>

F-Droid/src/org/fdroid/fdroid/localrepo/SwapService.java

@@ -58,8 +58,7 @@ import java.util.TimerTask;
 
 /**
  * Central service which manages all of the different moving parts of swap which are required
- * to enable p2p swapping of apps. Currently manages WiFi and NFC. Will manage Bluetooth in
+ * to enable p2p swapping of apps.
- * the future.
  *
  * TODO: Show "Waiting for other device to finish setting up swap" when only F-Droid shown in swap
  * TODO: Handle "not connected to wifi" more gracefully. For example, Bonjour discovery falls over.
@@ -68,6 +67,7 @@ import java.util.TimerTask;
  * TODO: Feedback for "Setting up (wifi|bluetooth)" in start swap view is not as immediate as I had hoped.
  * TODO: Turn off bluetooth after cancelling/timing out if we turned it on.
  * TODO: Disable the Scan QR button unless visible via something. Could equally show relevant feedback.
+ * TODO: Implement "Send F-Droid" on the main page.
  *
  * TODO: Starting wifi after cancelling swap and beginning again doesn't work properly
  * TODO: Scan QR hangs when updating repoo. Swapper was 2.3.3 and Swappee was 5.0

F-Droid/src/org/fdroid/fdroid/views/swap/StartSwapView.java

@@ -141,7 +141,7 @@ public class StartSwapView extends ScrollView implements SwapWorkflowActivity.In
         findViewById(R.id.btn_qr_scanner).setOnClickListener(new OnClickListener() {
             @Override
             public void onClick(View v) {
-                getActivity().showSelectApps();
+                getActivity().startQrWorkflow();
             }
         });
     }

F-Droid/src/org/fdroid/fdroid/views/swap/SwapWorkflowActivity.java

@@ -5,6 +5,7 @@ import android.app.ProgressDialog;
 import android.content.ComponentName;
 import android.bluetooth.BluetoothAdapter;
 import android.content.Context;
+import android.content.DialogInterface;
 import android.content.Intent;
 import android.content.ServiceConnection;
 import android.net.Uri;
@@ -17,6 +18,7 @@ import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
 import android.support.v4.app.NavUtils;
 import android.support.v4.content.LocalBroadcastManager;
+import android.support.v7.app.AlertDialog;
 import android.support.v7.app.AppCompatActivity;
 import android.support.v7.widget.Toolbar;
 import android.util.Log;
@@ -332,6 +334,24 @@ public class SwapWorkflowActivity extends AppCompatActivity {
         ((ConfirmReceive)inflateInnerView(R.layout.swap_confirm_receive)).setup(config);
     }
 
+    public void startQrWorkflow() {
+        if (!getService().isEnabled()) {
+            new AlertDialog.Builder(this)
+                    .setTitle(R.string.swap_not_enabled)
+                    .setMessage(R.string.swap_not_enabled_description)
+                    .setCancelable(true)
+                    .setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
+                        @Override
+                        public void onClick(DialogInterface dialog, int which) {
+                            // Do nothing. The dialog will get dismissed anyway, which is all we ever wanted...
+                        }
+                    })
+                    .create().show();
+        } else {
+            showSelectApps();
+        }
+    }
+
     public void showSelectApps() {
         inflateInnerView(R.layout.swap_select_apps);
     }