Write wifi config to NFC tag

Configured networks expose the option to
write config to an NFC tag. This tag can be
then tapped to another device to configure
the same network. Implemented according to
WiFi Alliance WPS spec.

Change-Id: I33a1be1610aab71cf1ab864418d494027370ebca

res/layout/write_wifi_config_to_nfc.xml

@@ -0,0 +1,42 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+            style="@style/wifi_section">
+
+    <LinearLayout android:id="@+id/password_layout"
+                  style="@style/wifi_item"
+                  android:padding="8dip"
+                  android:orientation="vertical" >
+
+        <TextView
+                android:id="@+id/password_label"
+                android:layout_gravity="fill"
+                style="@style/wifi_item_label"
+                android:text="@string/wifi_password" />
+
+        <EditText android:id="@+id/password"
+                  style="@style/wifi_item_edit_content"
+                  android:singleLine="true"
+                  android:password="true" />
+
+        <TextView
+                style="@style/wifi_item_label" />
+
+        <CheckBox android:id="@+id/show_password"
+                  style="@style/wifi_item_content"
+                  android:textSize="14sp"
+                  android:text="@string/wifi_show_password" />
+
+    </LinearLayout>
+
+
+    <ProgressBar
+            android:id="@+id/progress_bar"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_gravity="center_vertical|center_horizontal"
+            android:padding="8dip"
+            android:visibility="gone"
+            style="@android:style/Widget.ProgressBar.Large" />
+
+</LinearLayout>

res/values/strings.xml

@@ -1494,6 +1494,8 @@
     <!-- Substring of wifi status for wifi with authentication.  This version is for when the
          string is not first in the list (lowercase in english) -->
     <string name="wifi_secured_second_item">, secured with <xliff:g id="wifi_security_short">%1$s</xliff:g></string>
+    <!-- Message in WriteWifiConfigToNfcDialog when prompted to enter network password [CHAR LIMIT=150] -->
+    <string name="wifi_wps_nfc_enter_password">Enter your network password.</string>
 
     <!-- Do not translate.  Concise terminology for wifi with WEP security -->
     <string name="wifi_security_short_wep">WEP</string>
@@ -5059,4 +5061,23 @@
     <!-- [CHAR LIMIT=NONE] Content description for per-app notification
          settings button -->
     <string name="notification_app_settings_button">Notification settings</string>
+
+    <!-- NFC WiFi pairing/setup strings-->
+
+    <!-- Write NFC tag for WiFi pairing/setup title -->
+    <string name="setup_wifi_nfc_tag">Set up WiFi NFC Tag</string>
+    <!-- Text for button to confirm writing tag -->
+    <string name="write_tag">Write</string>
+    <!-- Text to inform the user to tap a tag to complete the setup process -->
+    <string name="status_awaiting_tap">Tap a tag to write...</string>
+    <!-- Text to inform the user that the network key entered was incorrect -->
+    <string name="status_invalid_password">Invalid password, try again.</string>
+    <!-- Text displayed when tag successfully writen -->
+    <string name="status_write_success">Success!</string>
+    <!-- Text displayed in error cases (failure to write to tag) -->
+    <string name="status_failed_to_write">Unable to write data to NFC tag. If the problem persists, try a different tag</string>
+    <!-- Text displayed when tag is not writable -->
+    <string name="status_tag_not_writable">NFC tag is not writable. Please use a different tag.</string>
+
+
 </resources>

src/com/android/settings/wifi/WifiSettings.java

@@ -94,6 +94,7 @@ import java.util.concurrent.atomic.AtomicBoolean;
  */
 public class WifiSettings extends RestrictedSettingsFragment
         implements DialogInterface.OnClickListener, Indexable  {
+
     private static final String TAG = "WifiSettings";
     private static final int MENU_ID_WPS_PBC = Menu.FIRST;
     private static final int MENU_ID_WPS_PIN = Menu.FIRST + 1;
@@ -104,12 +105,14 @@ public class WifiSettings extends RestrictedSettingsFragment
     private static final int MENU_ID_CONNECT = Menu.FIRST + 6;
     private static final int MENU_ID_FORGET = Menu.FIRST + 7;
     private static final int MENU_ID_MODIFY = Menu.FIRST + 8;
+    private static final int MENU_ID_WRITE_NFC = Menu.FIRST + 9;
 
     private static final int WIFI_DIALOG_ID = 1;
     private static final int WPS_PBC_DIALOG_ID = 2;
     private static final int WPS_PIN_DIALOG_ID = 3;
     private static final int WIFI_SKIPPED_DIALOG_ID = 4;
     private static final int WIFI_AND_MOBILE_SKIPPED_DIALOG_ID = 5;
+    private static final int WRITE_NFC_DIALOG_ID = 6;
 
     // Combo scans can take 5-6s to complete - set to 10s.
     private static final int WIFI_RESCAN_INTERVAL_MS = 10 * 1000;
@@ -141,6 +144,7 @@ public class WifiSettings extends RestrictedSettingsFragment
     private final AtomicBoolean mConnected = new AtomicBoolean(false);
 
     private WifiDialog mDialog;
+    private WriteWifiConfigToNfcDialog mWifiToNfcDialog;
 
     private TextView mEmptyView;
 
@@ -205,13 +209,13 @@ public class WifiSettings extends RestrictedSettingsFragment
     public void onCreate(Bundle icicle) {
         // Set this flag early, as it's needed by getHelpResource(), which is called by super
         mSetupWizardMode = getActivity().getIntent().getBooleanExtra(EXTRA_IS_FIRST_RUN, false);
-
         super.onCreate(icicle);
     }
 
     @Override
     public View onCreateView(final LayoutInflater inflater, ViewGroup container,
             Bundle savedInstanceState) {
+
         if (mSetupWizardMode) {
             View view = inflater.inflate(R.layout.setup_preference, container, false);
             View other = view.findViewById(R.id.other_network);
@@ -471,6 +475,7 @@ public class WifiSettings extends RestrictedSettingsFragment
         if (mWifiEnabler != null) {
             mWifiEnabler.pause();
         }
+
         getActivity().unregisterReceiver(mReceiver);
         mScanner.pause();
     }
@@ -599,6 +604,11 @@ public class WifiSettings extends RestrictedSettingsFragment
                 if (mSelectedAccessPoint.networkId != INVALID_NETWORK_ID) {
                     menu.add(Menu.NONE, MENU_ID_FORGET, 0, R.string.wifi_menu_forget);
                     menu.add(Menu.NONE, MENU_ID_MODIFY, 0, R.string.wifi_menu_modify);
+
+                    if (mSelectedAccessPoint.security != AccessPoint.SECURITY_NONE) {
+                        // Only allow writing of NFC tags for password-protected networks.
+                        menu.add(Menu.NONE, MENU_ID_WRITE_NFC, 0, "Write to NFC Tag");
+                    }
                 }
             }
         }
@@ -632,6 +642,10 @@ public class WifiSettings extends RestrictedSettingsFragment
                 showDialog(mSelectedAccessPoint, true);
                 return true;
             }
+            case MENU_ID_WRITE_NFC:
+                showDialog(WRITE_NFC_DIALOG_ID);
+                return true;
+
         }
         return super.onContextItemSelected(item);
     }
@@ -681,7 +695,7 @@ public class WifiSettings extends RestrictedSettingsFragment
                         mAccessPointSavedState = null;
                     }
                 }
-                // If it's still null, fine, it's for Add Network
+                // If it's null, fine, it's for Add Network
                 mSelectedAccessPoint = ap;
                 mDialog = new WifiDialog(getActivity(), this, ap, mDlgEdit);
                 return mDialog;
@@ -727,6 +741,10 @@ public class WifiSettings extends RestrictedSettingsFragment
                                 }
                             })
                             .create();
+            case WRITE_NFC_DIALOG_ID:
+                mWifiToNfcDialog =new WriteWifiConfigToNfcDialog(
+                        getActivity(), mSelectedAccessPoint, mWifiManager);
+                return mWifiToNfcDialog;
 
         }
         return super.onCreateDialog(dialogId);
@@ -991,8 +1009,7 @@ public class WifiSettings extends RestrictedSettingsFragment
                 mRetry = 0;
                 Activity activity = getActivity();
                 if (activity != null) {
-                    Toast.makeText(activity, R.string.wifi_fail_to_scan,
+                    Toast.makeText(activity, R.string.wifi_fail_to_scan, Toast.LENGTH_LONG).show();
-                            Toast.LENGTH_LONG).show();
                 }
                 return;
             }

src/com/android/settings/wifi/WriteWifiConfigToNfcDialog.java

@@ -0,0 +1,264 @@
+package com.android.settings.wifi;
+
+import android.app.Activity;
+import android.app.AlertDialog;
+import android.content.Context;
+import android.content.DialogInterface;
+import android.net.wifi.WifiManager;
+import android.nfc.FormatException;
+import android.nfc.NdefMessage;
+import android.nfc.NdefRecord;
+import android.nfc.NfcAdapter;
+import android.nfc.Tag;
+import android.nfc.tech.Ndef;
+import android.os.Bundle;
+import android.os.Handler;
+import android.os.PowerManager;
+import android.text.Editable;
+import android.text.InputType;
+import android.text.TextWatcher;
+import android.util.Log;
+import android.view.Gravity;
+import android.view.View;
+import android.view.inputmethod.InputMethodManager;
+import android.widget.Button;
+import android.widget.CheckBox;
+import android.widget.CompoundButton;
+import android.widget.LinearLayout;
+import android.widget.ProgressBar;
+import android.widget.TextView;
+
+import com.android.settings.R;
+
+import java.io.IOException;
+
+class WriteWifiConfigToNfcDialog extends AlertDialog
+        implements TextWatcher, View.OnClickListener, CompoundButton.OnCheckedChangeListener {
+
+    private static final String NFC_TOKEN_MIME_TYPE = "application/vnd.wfa.wsc";
+
+    private static final String TAG = WriteWifiConfigToNfcDialog.class.getName().toString();
+    private static final String PASSWORD_FORMAT = "102700%s%s";
+
+    private final PowerManager.WakeLock mWakeLock;
+
+    private AccessPoint mAccessPoint;
+    private View mView;
+    private Button mSubmitButton;
+    private Button mCancelButton;
+    private Handler mOnTextChangedHandler;
+    private TextView mPasswordView;
+    private TextView mLabelView;
+    private CheckBox mPasswordCheckBox;
+    private ProgressBar mProgressBar;
+    private WifiManager mWifiManager;
+    private String mWpsNfcConfigurationToken;
+    private Context mContext;
+
+    WriteWifiConfigToNfcDialog(Context context, AccessPoint accessPoint,
+            WifiManager wifiManager) {
+        super(context);
+        this.mContext = context;
+        this.mWakeLock = ((PowerManager) context.getSystemService(Context.POWER_SERVICE))
+                .newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "WriteWifiConfigToNfcDialog:wakeLock");
+        this.mAccessPoint = accessPoint;
+        this.mOnTextChangedHandler = new Handler();
+        this.mWifiManager = wifiManager;
+    }
+
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        mView = getLayoutInflater().inflate(R.layout.write_wifi_config_to_nfc, null);
+
+        setView(mView);
+        setInverseBackgroundForced(true);
+        setTitle(R.string.setup_wifi_nfc_tag);
+        setCancelable(true);
+        setButton(DialogInterface.BUTTON_NEUTRAL,
+                mContext.getResources().getString(R.string.write_tag), (OnClickListener) null);
+        setButton(DialogInterface.BUTTON_NEGATIVE,
+                mContext.getResources().getString(com.android.internal.R.string.cancel),
+                (OnClickListener) null);
+
+        mPasswordView = (TextView) mView.findViewById(R.id.password);
+        mLabelView = (TextView) mView.findViewById(R.id.password_label);
+        mPasswordView.addTextChangedListener(this);
+        mPasswordCheckBox = (CheckBox) mView.findViewById(R.id.show_password);
+        mPasswordCheckBox.setOnCheckedChangeListener(this);
+        mProgressBar = (ProgressBar) mView.findViewById(R.id.progress_bar);
+
+        super.onCreate(savedInstanceState);
+
+        mSubmitButton = getButton(DialogInterface.BUTTON_NEUTRAL);
+        mSubmitButton.setOnClickListener(this);
+        mSubmitButton.setEnabled(false);
+
+        mCancelButton = getButton(DialogInterface.BUTTON_NEGATIVE);
+    }
+
+    @Override
+    public void onClick(View v) {
+        mWakeLock.acquire();
+
+        String password = mPasswordView.getText().toString();
+        String wpsNfcConfigurationToken
+                = mWifiManager.getWpsNfcConfigurationToken(mAccessPoint.networkId);
+        String passwordHex = byteArrayToHexString(password.getBytes());
+
+        String passwordLength = password.length() >= 16
+                ? "" + Character.forDigit(password.length(), 16)
+                : "0" + Character.forDigit(password.length(), 16);
+
+        passwordHex = String.format(PASSWORD_FORMAT, passwordLength, passwordHex).toUpperCase();
+
+        if (wpsNfcConfigurationToken.contains(passwordHex)) {
+            mWpsNfcConfigurationToken = wpsNfcConfigurationToken;
+
+            Activity activity = getOwnerActivity();
+            NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(activity);
+
+            nfcAdapter.enableReaderMode(activity, new NfcAdapter.ReaderCallback() {
+                @Override
+                public void onTagDiscovered(Tag tag) {
+                    handleWriteNfcEvent(tag);
+                }
+            }, NfcAdapter.FLAG_READER_NFC_A |
+                    NfcAdapter.FLAG_READER_NFC_B |
+                    NfcAdapter.FLAG_READER_NFC_BARCODE |
+                    NfcAdapter.FLAG_READER_NFC_F |
+                    NfcAdapter.FLAG_READER_NFC_V,
+                    null);
+
+            mPasswordView.setVisibility(View.GONE);
+            mPasswordCheckBox.setVisibility(View.GONE);
+            mSubmitButton.setVisibility(View.GONE);
+            InputMethodManager imm = (InputMethodManager)
+                    getOwnerActivity().getSystemService(Context.INPUT_METHOD_SERVICE);
+            imm.hideSoftInputFromWindow(mPasswordView.getWindowToken(), 0);
+
+            mLabelView.setText(R.string.status_awaiting_tap);
+
+            mView.findViewById(R.id.password_layout).setTextAlignment(View.TEXT_ALIGNMENT_CENTER);
+            mProgressBar.setVisibility(View.VISIBLE);
+        } else {
+            mLabelView.setText(R.string.status_invalid_password);
+        }
+    }
+
+    private void handleWriteNfcEvent(Tag tag) {
+        Ndef ndef = Ndef.get(tag);
+
+        if (ndef != null) {
+            if (ndef.isWritable()) {
+                NdefRecord record = NdefRecord.createMime(
+                        NFC_TOKEN_MIME_TYPE,
+                        hexStringToByteArray(mWpsNfcConfigurationToken));
+                try {
+                    ndef.connect();
+                    ndef.writeNdefMessage(new NdefMessage(record));
+                    getOwnerActivity().runOnUiThread(new Runnable() {
+                        @Override
+                        public void run() {
+                            mProgressBar.setVisibility(View.GONE);
+                        }
+                    });
+                    setViewText(mLabelView, R.string.status_write_success);
+                    setViewText(mCancelButton, com.android.internal.R.string.done_label);
+                } catch (IOException e) {
+                    setViewText(mLabelView, R.string.status_failed_to_write);
+                    Log.e(TAG, "Unable to write WiFi config to NFC tag.", e);
+                    return;
+                } catch (FormatException e) {
+                    setViewText(mLabelView, R.string.status_failed_to_write);
+                    Log.e(TAG, "Unable to write WiFi config to NFC tag.", e);
+                    return;
+                }
+            } else {
+                setViewText(mLabelView, R.string.status_tag_not_writable);
+                Log.e(TAG, "Tag is not writable");
+            }
+        } else {
+            setViewText(mLabelView, R.string.status_tag_not_writable);
+            Log.e(TAG, "Tag does not support NDEF");
+        }
+    }
+
+    @Override
+    public void dismiss() {
+        if (mWakeLock.isHeld()) {
+            mWakeLock.release();
+        }
+
+        super.dismiss();
+    }
+
+    @Override
+    public void onTextChanged(CharSequence s, int start, int before, int count) {
+        mOnTextChangedHandler.post(new Runnable() {
+            @Override
+            public void run() {
+                enableSubmitIfAppropriate();
+            }
+        });
+    }
+
+    private void enableSubmitIfAppropriate() {
+
+        if (mPasswordView != null) {
+            if (mAccessPoint.security == AccessPoint.SECURITY_WEP) {
+                mSubmitButton.setEnabled(mPasswordView.length() > 0);
+            } else if (mAccessPoint.security == AccessPoint.SECURITY_PSK) {
+                mSubmitButton.setEnabled(mPasswordView.length() >= 8);
+            }
+        } else {
+            mSubmitButton.setEnabled(false);
+        }
+
+    }
+
+    private void setViewText(final TextView view, final int resid) {
+        getOwnerActivity().runOnUiThread(new Runnable() {
+            @Override
+            public void run() {
+                view.setText(resid);
+            }
+        });
+    }
+
+    @Override
+    public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
+        mPasswordView.setInputType(
+                InputType.TYPE_CLASS_TEXT |
+                (isChecked
+                        ? InputType.TYPE_TEXT_VARIATION_VISIBLE_PASSWORD
+                        : InputType.TYPE_TEXT_VARIATION_PASSWORD));
+    }
+
+    private static byte[] hexStringToByteArray(String s) {
+        int len = s.length();
+        byte[] data = new byte[len / 2];
+
+        for (int i = 0; i < len; i += 2) {
+            data[i / 2] = (byte) ((Character.digit(s.charAt(i), 16) << 4)
+                    + Character.digit(s.charAt(i + 1), 16));
+        }
+
+        return data;
+    }
+
+    final protected static char[] hexArray = "0123456789ABCDEF".toCharArray();
+    private static String byteArrayToHexString(byte[] bytes) {
+        char[] hexChars = new char[bytes.length * 2];
+        for ( int j = 0; j < bytes.length; j++ ) {
+            int v = bytes[j] & 0xFF;
+            hexChars[j * 2] = hexArray[v >>> 4];
+            hexChars[j * 2 + 1] = hexArray[v & 0x0F];
+        }
+        return new String(hexChars);
+    }
+
+    @Override
+    public void beforeTextChanged(CharSequence s, int start, int count, int after) {}
+    @Override
+    public void afterTextChanged(Editable s) {}
+}