integrate NFC into key view and import activities

OpenPGP-Keychain/AndroidManifest.xml

@@ -276,8 +276,17 @@
         <activity
             android:name=".ui.ImportKeysActivity"
             android:label="@string/title_import_keys"
+            android:launchMode="singleTop"
             android:windowSoftInputMode="stateHidden" >
 
+            <!-- Handle NFC tags detected from outside our application -->
+            <intent-filter>
+                <action android:name="android.nfc.action.NDEF_DISCOVERED" />
+
+                <category android:name="android.intent.category.DEFAULT" />
+                <!-- mime type as defined in http://tools.ietf.org/html/rfc3156, section 7 -->
+                <data android:mimeType="application/pgp-keys" />
+            </intent-filter>
             <!-- Keychain's own Actions -->
             <intent-filter android:label="@string/intent_import_key" >
                 <action android:name="org.sufficientlysecure.keychain.action.IMPORT_KEY" />
@@ -336,21 +345,6 @@
                 <data android:pathPattern=".*\\..*\\..*\\..*\\..*\\..*\\..*\\..*\\..*\\..*\\.asc" />
             </intent-filter>
         </activity>
-        <activity
-            android:name=".ui.ShareNfcBeamActivity"
-            android:label="@string/title_share_by_nfc"
-            android:launchMode="singleTop"
-            android:uiOptions="splitActionBarWhenNarrow" >
-
-            <!-- Handle NFC tags detected from outside our application -->
-            <intent-filter>
-                <action android:name="android.nfc.action.NDEF_DISCOVERED" />
-
-                <category android:name="android.intent.category.DEFAULT" />
-                <!-- mime type as defined in http://tools.ietf.org/html/rfc3156, section 7 -->
-                <data android:mimeType="application/pgp-keys" />
-            </intent-filter>
-        </activity>
         <activity
             android:name=".ui.HelpActivity"
             android:label="@string/title_help" />

OpenPGP-Keychain/res/menu/nfc_beam.xml

@@ -1,10 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<menu xmlns:android="http://schemas.android.com/apk/res/android" >
-
-    <item
-        android:id="@+id/menu_settings"
-        android:icon="@drawable/ic_menu_settings"
-        android:showAsAction="always|withText"
-        android:title="@string/menu_beam_preferences"/>
-
-</menu>

OpenPGP-Keychain/src/org/sufficientlysecure/keychain/ui/ImportKeysActivity.java

@@ -19,7 +19,6 @@ package org.sufficientlysecure.keychain.ui;
 
 import java.util.ArrayList;
 import java.util.List;
-
 import org.sufficientlysecure.keychain.Constants;
 import org.sufficientlysecure.keychain.R;
 import org.sufficientlysecure.keychain.helper.ActionBarHelper;
@@ -29,21 +28,23 @@ import org.sufficientlysecure.keychain.ui.adapter.ImportKeysListEntry;
 import org.sufficientlysecure.keychain.ui.dialog.DeleteFileDialogFragment;
 import org.sufficientlysecure.keychain.ui.dialog.FileDialogFragment;
 import org.sufficientlysecure.keychain.util.Log;
-
+import android.annotation.SuppressLint;
 import android.app.AlertDialog;
 import android.app.ProgressDialog;
 import android.content.Context;
 import android.content.DialogInterface;
 import android.content.Intent;
+import android.nfc.NdefMessage;
+import android.nfc.NfcAdapter;
 import android.os.Bundle;
 import android.os.Message;
 import android.os.Messenger;
+import android.os.Parcelable;
 import android.support.v4.app.Fragment;
 import android.support.v4.app.FragmentTransaction;
 import android.view.View;
 import android.widget.ArrayAdapter;
 import android.widget.Toast;
-
 import com.actionbarsherlock.app.ActionBar;
 import com.actionbarsherlock.app.ActionBar.OnNavigationListener;
 import com.actionbarsherlock.app.SherlockFragmentActivity;
@@ -345,7 +346,8 @@ public class ImportKeysActivity extends SherlockFragmentActivity implements OnNa
                         int bad = returnData.getInt(KeychainIntentService.RESULT_IMPORT_BAD);
                         String toastMessage;
                         if (added > 0 && updated > 0) {
-                            toastMessage = getString(R.string.keys_added_and_updated, added, updated);
+                            toastMessage = getString(R.string.keys_added_and_updated, added,
+                                    updated);
                         } else if (added > 0) {
                             toastMessage = getString(R.string.keys_added, added);
                         } else if (updated > 0) {
@@ -409,4 +411,43 @@ public class ImportKeysActivity extends SherlockFragmentActivity implements OnNa
                 .show();
     }
 
+    /**
+     * NFC
+     */
+    @Override
+    public void onResume() {
+        super.onResume();
+        // Check to see that the Activity started due to an Android Beam
+        if (NfcAdapter.ACTION_NDEF_DISCOVERED.equals(getIntent().getAction())) {
+            handleActionNdefDiscovered(getIntent());
+        }
+    }
+
+    /**
+     * NFC
+     */
+    @Override
+    public void onNewIntent(Intent intent) {
+        // onResume gets called after this to handle the intent
+        setIntent(intent);
+    }
+
+    /**
+     * NFC: Parses the NDEF Message from the intent and prints to the TextView
+     */
+    @SuppressLint("NewApi")
+    void handleActionNdefDiscovered(Intent intent) {
+        Parcelable[] rawMsgs = intent.getParcelableArrayExtra(NfcAdapter.EXTRA_NDEF_MESSAGES);
+        // only one message sent during the beam
+        NdefMessage msg = (NdefMessage) rawMsgs[0];
+        // record 0 contains the MIME type, record 1 is the AAR, if present
+        byte[] receivedKeyringBytes = msg.getRecords()[0].getPayload();
+
+        Intent importIntent = new Intent(this, ImportKeysActivity.class);
+        importIntent.setAction(ImportKeysActivity.ACTION_IMPORT_KEY);
+        importIntent.putExtra(ImportKeysActivity.EXTRA_KEY_BYTES, receivedKeyringBytes);
+
+        handleActions(null, importIntent);
+    }
+
 }

OpenPGP-Keychain/src/org/sufficientlysecure/keychain/ui/KeyViewActivity.java

@@ -1,6 +1,6 @@
 /*
- * Copyright (C) 2013 Bahtiar 'kalkin' Gadimov
  * Copyright (C) 2013 Dominik Schürmann <dominik@dominikschuermann.de>
+ * Copyright (C) 2013 Bahtiar 'kalkin' Gadimov
  *
  * 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
@@ -30,21 +30,34 @@ import org.sufficientlysecure.keychain.Id;
 import org.sufficientlysecure.keychain.R;
 import org.sufficientlysecure.keychain.pgp.PgpKeyHelper;
 import org.sufficientlysecure.keychain.provider.ProviderHelper;
+import org.sufficientlysecure.keychain.ui.dialog.ShareNfcDialogFragment;
 import org.sufficientlysecure.keychain.ui.dialog.ShareQrCodeDialogFragment;
 import org.sufficientlysecure.keychain.util.Log;
 
+import android.annotation.SuppressLint;
 import android.content.Intent;
 import android.net.Uri;
+import android.nfc.NdefMessage;
+import android.nfc.NdefRecord;
+import android.nfc.NfcAdapter;
+import android.nfc.NfcAdapter.CreateNdefMessageCallback;
+import android.nfc.NfcAdapter.OnNdefPushCompleteCallback;
+import android.nfc.NfcEvent;
+import android.os.Build;
 import android.os.Bundle;
+import android.os.Handler;
+import android.os.Message;
 import android.text.format.DateFormat;
 import android.widget.TextView;
+import android.widget.Toast;
 
-import com.actionbarsherlock.app.SherlockActivity;
 import com.actionbarsherlock.app.SherlockFragmentActivity;
 import com.actionbarsherlock.view.Menu;
 import com.actionbarsherlock.view.MenuItem;
 
-public class KeyViewActivity extends SherlockFragmentActivity {
+@SuppressLint("NewApi")
+public class KeyViewActivity extends SherlockFragmentActivity implements CreateNdefMessageCallback,
+        OnNdefPushCompleteCallback {
     private Uri mDataUri;
 
     private PGPPublicKey mPublicKey;
@@ -54,6 +67,11 @@ public class KeyViewActivity extends SherlockFragmentActivity {
     private TextView mExpiry;
     private TextView mCreation;
 
+    // NFC
+    private NfcAdapter mNfcAdapter;
+    private byte[] mSharedKeyringBytes;
+    private static final int NFC_SENT = 1;
+
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
@@ -77,6 +95,7 @@ public class KeyViewActivity extends SherlockFragmentActivity {
         } else {
             Log.d(Constants.TAG, "uri: " + mDataUri);
             loadData(mDataUri);
+            initNfc();
         }
     }
 
@@ -154,12 +173,14 @@ public class KeyViewActivity extends SherlockFragmentActivity {
             return true;
         case R.id.menu_key_view_share_nfc:
             // get master key id using row id
-            long masterKeyId2 = ProviderHelper.getPublicMasterKeyId(this, keyRingRowId);
+            // long masterKeyId2 = ProviderHelper.getPublicMasterKeyId(this, keyRingRowId);
+            //
+            // Intent nfcIntent = new Intent(this, ShareNfcBeamActivity.class);
+            // nfcIntent.setAction(ShareNfcBeamActivity.ACTION_SHARE_KEYRING_WITH_NFC);
+            // nfcIntent.putExtra(ShareNfcBeamActivity.EXTRA_MASTER_KEY_ID, masterKeyId2);
+            // startActivityForResult(nfcIntent, 0);
 
-            Intent nfcIntent = new Intent(this, ShareNfcBeamActivity.class);
+            shareNfc();
-            nfcIntent.setAction(ShareNfcBeamActivity.ACTION_SHARE_KEYRING_WITH_NFC);
-            nfcIntent.putExtra(ShareNfcBeamActivity.EXTRA_MASTER_KEY_ID, masterKeyId2);
-            startActivityForResult(nfcIntent, 0);
 
             return true;
         case R.id.menu_key_view_delete:
@@ -191,8 +212,10 @@ public class KeyViewActivity extends SherlockFragmentActivity {
         mAlgorithm.setText(PgpKeyHelper.getAlgorithmInfo(mPublicKey));
     }
 
+    /**
+     * TODO: does this duplicate functionality from elsewhere? put in helper!
+     */
     private String[] splitUserId(String userId) {
-
         String[] result = new String[] { "", "", "" };
         Log.v("UserID", userId);
 
@@ -219,7 +242,6 @@ public class KeyViewActivity extends SherlockFragmentActivity {
         // TODO: use data uri!
         long keyRingRowId = Long.valueOf(mDataUri.getLastPathSegment());
         long masterKeyId = ProviderHelper.getPublicMasterKeyId(this, keyRingRowId);
-
         // get public keyring as ascii armored string
         ArrayList<String> keyringArmored = ProviderHelper.getPublicKeyRingsAsArmoredString(this,
                 new long[] { masterKeyId });
@@ -242,6 +264,79 @@ public class KeyViewActivity extends SherlockFragmentActivity {
 
         ShareQrCodeDialogFragment dialog = ShareQrCodeDialogFragment.newInstance(keyringArmored
                 .get(0));
-        dialog.show(getSupportFragmentManager(), "qrCodeShareDialog");
+        dialog.show(getSupportFragmentManager(), "shareQrCodeDialog");
     }
+
+    private void shareNfc() {
+        ShareNfcDialogFragment dialog = ShareNfcDialogFragment.newInstance();
+        dialog.show(getSupportFragmentManager(), "shareNfcDialog");
+    }
+
+    /**
+     * NFC: Initialize NFC sharing if OS and device supports it
+     */
+    private void initNfc() {
+        // check if NFC Beam is supported (>= Android 4.1)
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
+            // Check for available NFC Adapter
+            mNfcAdapter = NfcAdapter.getDefaultAdapter(this);
+            if (mNfcAdapter != null) {
+                // init nfc
+                // TODO: use data uri!
+                long keyRingRowId = Long.valueOf(mDataUri.getLastPathSegment());
+                long masterKeyId = ProviderHelper.getPublicMasterKeyId(this, keyRingRowId);
+
+                // get public keyring as byte array
+                mSharedKeyringBytes = ProviderHelper.getPublicKeyRingsAsByteArray(this,
+                        new long[] { masterKeyId });
+
+                // Register callback to set NDEF message
+                mNfcAdapter.setNdefPushMessageCallback(this, this);
+                // Register callback to listen for message-sent success
+                mNfcAdapter.setOnNdefPushCompleteCallback(this, this);
+            }
+        }
+    }
+
+    /**
+     * NFC: Implementation for the CreateNdefMessageCallback interface
+     */
+    @Override
+    public NdefMessage createNdefMessage(NfcEvent event) {
+        /**
+         * When a device receives a push with an AAR in it, the application specified in the AAR is
+         * guaranteed to run. The AAR overrides the tag dispatch system. You can add it back in to
+         * guarantee that this activity starts when receiving a beamed message. For now, this code
+         * uses the tag dispatch system.
+         */
+        NdefMessage msg = new NdefMessage(NdefRecord.createMime(Constants.NFC_MIME,
+                mSharedKeyringBytes), NdefRecord.createApplicationRecord(Constants.PACKAGE_NAME));
+        return msg;
+    }
+
+    /**
+     * NFC: Implementation for the OnNdefPushCompleteCallback interface
+     */
+    @Override
+    public void onNdefPushComplete(NfcEvent arg0) {
+        // A handler is needed to send messages to the activity when this
+        // callback occurs, because it happens from a binder thread
+        mNfcHandler.obtainMessage(NFC_SENT).sendToTarget();
+    }
+
+    /**
+     * NFC: This handler receives a message from onNdefPushComplete
+     */
+    private final Handler mNfcHandler = new Handler() {
+        @Override
+        public void handleMessage(Message msg) {
+            switch (msg.what) {
+            case NFC_SENT:
+                Toast.makeText(getApplicationContext(), R.string.nfc_successfull, Toast.LENGTH_LONG)
+                        .show();
+                break;
+            }
+        }
+    };
+
 }

OpenPGP-Keychain/src/org/sufficientlysecure/keychain/ui/ShareNfcBeamActivity.java

@@ -1,226 +0,0 @@
-/*
- * Copyright (C) 2013 Dominik Schürmann <dominik@dominikschuermann.de>
- * Copyright (C) 2011 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.
- */
-
-package org.sufficientlysecure.keychain.ui;
-
-import org.sufficientlysecure.htmltextview.HtmlTextView;
-import org.sufficientlysecure.keychain.Constants;
-import org.sufficientlysecure.keychain.R;
-import org.sufficientlysecure.keychain.helper.ActionBarHelper;
-import org.sufficientlysecure.keychain.provider.ProviderHelper;
-
-import android.annotation.TargetApi;
-import android.content.Intent;
-import android.nfc.NdefMessage;
-import android.nfc.NdefRecord;
-import android.nfc.NfcAdapter;
-import android.nfc.NfcAdapter.CreateNdefMessageCallback;
-import android.nfc.NfcAdapter.OnNdefPushCompleteCallback;
-import android.nfc.NfcEvent;
-import android.os.Build;
-import android.os.Bundle;
-import android.os.Handler;
-import android.os.Message;
-import android.os.Parcelable;
-import android.provider.Settings;
-import android.widget.Toast;
-
-import com.actionbarsherlock.app.SherlockFragmentActivity;
-import com.actionbarsherlock.view.Menu;
-import com.actionbarsherlock.view.MenuInflater;
-import com.actionbarsherlock.view.MenuItem;
-
-@TargetApi(Build.VERSION_CODES.JELLY_BEAN)
-public class ShareNfcBeamActivity extends SherlockFragmentActivity implements
-        CreateNdefMessageCallback, OnNdefPushCompleteCallback {
-    public static final String ACTION_SHARE_KEYRING_WITH_NFC = Constants.INTENT_PREFIX
-            + "SHARE_KEYRING_WITH_NFC";
-
-    public static final String EXTRA_MASTER_KEY_ID = "master_key_id";
-
-    NfcAdapter mNfcAdapter;
-
-    byte[] mSharedKeyringBytes;
-
-    private static final int MESSAGE_SENT = 1;
-
-    @Override
-    public void onCreate(Bundle savedInstanceState) {
-        super.onCreate(savedInstanceState);
-
-        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN) {
-            Toast.makeText(this,
-                    getString(R.string.error) + ": " + getString(R.string.error_jelly_bean_needed),
-                    Toast.LENGTH_LONG).show();
-            finish();
-        } else {
-            // Check for available NFC Adapter
-            mNfcAdapter = NfcAdapter.getDefaultAdapter(this);
-            if (mNfcAdapter == null) {
-                Toast.makeText(this,
-                        getString(R.string.error) + ": " + getString(R.string.error_nfc_needed),
-                        Toast.LENGTH_LONG).show();
-                finish();
-            } else {
-                // handle actions after verifying that nfc works...
-                handleActions(getIntent());
-            }
-        }
-    }
-
-    protected void handleActions(Intent intent) {
-        String action = intent.getAction();
-        Bundle extras = intent.getExtras();
-
-        if (extras == null) {
-            extras = new Bundle();
-        }
-
-        if (ACTION_SHARE_KEYRING_WITH_NFC.equals(action)) {
-            long masterKeyId = extras.getLong(EXTRA_MASTER_KEY_ID);
-
-            // get public keyring as byte array
-            mSharedKeyringBytes = ProviderHelper.getPublicKeyRingsAsByteArray(this,
-                    new long[] { masterKeyId });
-
-            // Register callback to set NDEF message
-            mNfcAdapter.setNdefPushMessageCallback(this, this);
-            // Register callback to listen for message-sent success
-            mNfcAdapter.setOnNdefPushCompleteCallback(this, this);
-        }
-    }
-
-    /**
-     * Parses the NDEF Message from the intent and prints to the TextView
-     */
-    void handleActionNdefDiscovered(Intent intent) {
-        Parcelable[] rawMsgs = intent.getParcelableArrayExtra(NfcAdapter.EXTRA_NDEF_MESSAGES);
-        // only one message sent during the beam
-        NdefMessage msg = (NdefMessage) rawMsgs[0];
-        // record 0 contains the MIME type, record 1 is the AAR, if present
-        byte[] receivedKeyringBytes = msg.getRecords()[0].getPayload();
-
-        Intent importIntent = new Intent(this, ImportKeysActivity.class);
-        importIntent.setAction(ImportKeysActivity.ACTION_IMPORT_KEY);
-        importIntent.putExtra(ImportKeysActivity.EXTRA_KEY_BYTES, receivedKeyringBytes);
-
-        finish();
-
-        startActivity(importIntent);
-    }
-
-    private void buildView() {
-        setContentView(R.layout.share_nfc_beam);
-
-        HtmlTextView aboutTextView = (HtmlTextView) findViewById(R.id.nfc_beam_text);
-
-        // load html from raw resource (Parsing handled by HtmlTextView library)
-        aboutTextView.setHtmlFromRawResource(this, R.raw.nfc_beam_share);
-
-        // no flickering when clicking textview for Android < 4
-        aboutTextView.setTextColor(getResources().getColor(android.R.color.black));
-
-        // set actionbar without home button if called from another app
-        ActionBarHelper.setBackButton(this);
-    }
-
-    /**
-     * Implementation for the CreateNdefMessageCallback interface
-     */
-    @Override
-    public NdefMessage createNdefMessage(NfcEvent event) {
-        /**
-         * When a device receives a push with an AAR in it, the application specified in the AAR is
-         * guaranteed to run. The AAR overrides the tag dispatch system. You can add it back in to
-         * guarantee that this activity starts when receiving a beamed message. For now, this code
-         * uses the tag dispatch system.
-         */
-        NdefMessage msg = new NdefMessage(NdefRecord.createMime(Constants.NFC_MIME,
-                mSharedKeyringBytes), NdefRecord.createApplicationRecord(Constants.PACKAGE_NAME));
-        return msg;
-    }
-
-    /**
-     * Implementation for the OnNdefPushCompleteCallback interface
-     */
-    @Override
-    public void onNdefPushComplete(NfcEvent arg0) {
-        // A handler is needed to send messages to the activity when this
-        // callback occurs, because it happens from a binder thread
-        mHandler.obtainMessage(MESSAGE_SENT).sendToTarget();
-    }
-
-    /** This handler receives a message from onNdefPushComplete */
-    private final Handler mHandler = new Handler() {
-        @Override
-        public void handleMessage(Message msg) {
-            switch (msg.what) {
-            case MESSAGE_SENT:
-                Toast.makeText(getApplicationContext(), R.string.nfc_successfull, Toast.LENGTH_LONG)
-                        .show();
-                break;
-            }
-        }
-    };
-
-    @Override
-    public void onResume() {
-        super.onResume();
-        // Check to see that the Activity started due to an Android Beam
-        if (NfcAdapter.ACTION_NDEF_DISCOVERED.equals(getIntent().getAction())) {
-            handleActionNdefDiscovered(getIntent());
-        } else {
-            // build view only when sending nfc, not when receiving, as it gets directly into Import
-            // activity on receiving
-            buildView();
-        }
-    }
-
-    @Override
-    public void onNewIntent(Intent intent) {
-        // onResume gets called after this to handle the intent
-        setIntent(intent);
-    }
-
-    @Override
-    public boolean onCreateOptionsMenu(Menu menu) {
-        MenuInflater inflater = getSupportMenuInflater();
-        inflater.inflate(R.menu.nfc_beam, menu);
-        return true;
-    }
-
-    @Override
-    public boolean onOptionsItemSelected(MenuItem item) {
-        switch (item.getItemId()) {
-
-        case android.R.id.home:
-            // app icon in Action Bar clicked; go to KeyListPublicActivity
-            Intent intent = new Intent(this, KeyListPublicActivity.class);
-            intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
-            startActivity(intent);
-            return true;
-
-        case R.id.menu_settings:
-            Intent intentSettings = new Intent(Settings.ACTION_NFCSHARING_SETTINGS);
-            startActivity(intentSettings);
-            return true;
-
-        default:
-            return super.onOptionsItemSelected(item);
-        }
-    }
-}

OpenPGP-Keychain/src/org/sufficientlysecure/keychain/ui/dialog/ShareNfcDialogFragment.java

@@ -0,0 +1,101 @@
+/*
+ * Copyright (C) 2013 Dominik Schürmann <dominik@dominikschuermann.de>
+ *
+ * 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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.sufficientlysecure.keychain.ui.dialog;
+
+import org.sufficientlysecure.htmltextview.HtmlTextView;
+import org.sufficientlysecure.keychain.R;
+
+import android.annotation.TargetApi;
+import android.app.AlertDialog;
+import android.app.Dialog;
+import android.content.DialogInterface;
+import android.content.Intent;
+import android.nfc.NfcAdapter;
+import android.os.Build;
+import android.os.Bundle;
+import android.provider.Settings;
+import android.support.v4.app.DialogFragment;
+import android.support.v4.app.FragmentActivity;
+
+@TargetApi(Build.VERSION_CODES.JELLY_BEAN)
+public class ShareNfcDialogFragment extends DialogFragment {
+
+    /**
+     * Creates new instance of this fragment
+     */
+    public static ShareNfcDialogFragment newInstance() {
+        ShareNfcDialogFragment frag = new ShareNfcDialogFragment();
+
+        return frag;
+    }
+
+    /**
+     * Creates dialog
+     */
+    @Override
+    public Dialog onCreateDialog(Bundle savedInstanceState) {
+        final FragmentActivity activity = getActivity();
+
+        AlertDialog.Builder alert = new AlertDialog.Builder(activity);
+
+        alert.setIcon(android.R.drawable.ic_dialog_alert);
+        alert.setTitle(R.string.warning);
+        alert.setCancelable(true);
+
+        alert.setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
+            @Override
+            public void onClick(DialogInterface dialog, int id) {
+                dismiss();
+            }
+        });
+
+        HtmlTextView textView = new HtmlTextView(getActivity());
+        textView.setPadding(8, 8, 8, 8);
+        alert.setView(textView);
+
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN) {
+            textView.setText(getString(R.string.error) + ": "
+                    + getString(R.string.error_jelly_bean_needed));
+        } else {
+            // check if NFC Adapter is available
+            NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(getActivity());
+            if (nfcAdapter == null) {
+                textView.setText(getString(R.string.error) + ": "
+                        + getString(R.string.error_nfc_needed));
+            } else {
+                // nfc works...
+                textView.setHtmlFromRawResource(getActivity(), R.raw.nfc_beam_share);
+
+                alert.setNegativeButton(R.string.menu_beam_preferences,
+                        new DialogInterface.OnClickListener() {
+                            @Override
+                            public void onClick(DialogInterface dialog, int id) {
+                                Intent intentSettings = new Intent(
+                                        Settings.ACTION_NFCSHARING_SETTINGS);
+                                startActivity(intentSettings);
+                            }
+                        });
+            }
+        }
+
+        // no flickering when clicking textview for Android < 4
+        // aboutTextView.setTextColor(getResources().getColor(android.R.color.black));
+
+        return alert.create();
+    }
+}