二维码是搭载信息的一种载体，通过二维码能够传递名片、网址、商品信息等，本文讲到二维码的第二种妙用：通过二维码实现wifi账号和password分享。

关于二维码的基础知识，请訪问：二维码的生成细节和原理

试想这样一种场景：一伙人去同一餐馆或者在一起开会，有的人之前去过且已经使用过那个场景的wifi账号。所以一去手机就能够直接连上那里的wifi，但有的同学是第一次去。也有连接wifi的需求，这时我们通常是通过别人告知wifi账号和password然后手动登陆。但问题是有时候已经连上wifi的人也不记得wifi的password了。本文结合这个需求场景。做了一个wifi账号和password分享的小demo。前提是两方都须要安装这个app，而且分享wifi的一方须要有root权限（眼下是。也能够将分享wifi的client作为热点，然后将热点分享给其它人，这个能够自行研究），这样降低了手动输入password的麻烦。

本文主要介绍通过二维码实现wifi分享的两个核心功能：

1、获取本机已经连接上的wifi账号、password和加密方式。

2、给定指定内容生成二维码，扫描二维码解析出当中搭载的信息。

1、获取本机已经连接上的wifi账号、password和加密方式：

全部的事情都能够通过以下这个类搞定：

public class WifiAdmin {public WifiAdmin(Context context) {   mWifiManager = (WifiManager) context.getSystemService(Context.WIFI_SERVICE);   mWifiInfo = mWifiManager.getConnectionInfo();   }   // 打开WIFI    public void openWifi() {   if (!mWifiManager.isWifiEnabled()) {   mWifiManager.setWifiEnabled(true);   }   }   // 关闭WIFI    public void closeWifi() {   if (mWifiManager.isWifiEnabled()) {   mWifiManager.setWifiEnabled(false);   }   }   // 检查当前WIFI状态    public int checkState() {   return mWifiManager.getWifiState();   }   // 锁定WifiLock    public void acquireWifiLock() {   mWifiLock.acquire();   }   // 解锁WifiLock    public void releaseWifiLock() {   // 推断时候锁定    if (mWifiLock.isHeld()) {   mWifiLock.acquire();   }   }   // 创建一个WifiLock    public void creatWifiLock() {   mWifiLock = mWifiManager.createWifiLock("Test");   }   // 得到配置好的网络    public List<WifiConfiguration> getConfiguration() {   return mWifiConfiguration;   }   // 指定配置好的网络进行连接    public void connectConfiguration(int index) {   // 索引大于配置好的网络索引返回    if (index > mWifiConfiguration.size()) {   return;   }   // 连接配置好的指定ID的网络    mWifiManager.enableNetwork(mWifiConfiguration.get(index).networkId,   true);   }   public void startScan() {   mWifiManager.startScan();   // 得到扫描结果    mWifiList = mWifiManager.getScanResults();   // 得到配置好的网络连接    mWifiConfiguration = mWifiManager.getConfiguredNetworks();   }   // 得到网络列表    public List<ScanResult> getWifiList() {   return mWifiList;   }   // 查看扫描结果    @SuppressLint("UseValueOf")public StringBuilder lookUpScan() {   StringBuilder stringBuilder = new StringBuilder();   for (int i = 0; i < mWifiList.size(); i++) {   stringBuilder.append("Index_" + new Integer(i + 1).toString() + ":");   // 将ScanResult信息转换成一个字符串包 当中把包含：BSSID、SSID、capabilities、frequency、level    stringBuilder.append((mWifiList.get(i)).toString());   stringBuilder.append("/n");   }   return stringBuilder;   }  // 得到MAC地址    public String getMacAddress() {   return (mWifiInfo == null) ? "NULL" : mWifiInfo.getMacAddress();   }   // 得到接入点的BSSID    public String getBSSID() {   return (mWifiInfo == null) ? "NULL" : mWifiInfo.getBSSID();   }   // 得到IP地址    public int getIPAddress() {   return (mWifiInfo == null) ? 0 : mWifiInfo.getIpAddress();   }   // 得到连接的ID    public int getNetworkId() {   return (mWifiInfo == null) ? 0 : mWifiInfo.getNetworkId();   }   // 得到WifiInfo的全部信息包    public WifiInfo getWifiInfo() {   return mWifiInfo;   }// 加入一个网络并连接    public void addNetwork(WifiConfiguration wcg) {   int wcgID = mWifiManager.addNetwork(wcg);   boolean b =  mWifiManager.enableNetwork(wcgID, true);   System.out.println("a--" + wcgID);  System.out.println("b--" + b);  }   // 断开指定ID的网络    public void disconnectWifi(int netId) {   mWifiManager.disableNetwork(netId);   mWifiManager.disconnect();   }   // 然后是一个实际应用方法。仅仅验证过没有密码的情况：// 分为三种情况：1没有密码2用wep加密3用wpa加密public WifiConfiguration CreateWifiInfo(String SSID, String password, int type) {WifiConfiguration config = new WifiConfiguration();config.allowedAuthAlgorithms.clear();config.allowedGroupCiphers.clear();config.allowedKeyManagement.clear();config.allowedPairwiseCiphers.clear();config.allowedProtocols.clear();config.SSID = "\"" + SSID + "\"";WifiConfiguration tempConfig = this.IsExsits(SSID);if (tempConfig != null) {mWifiManager.removeNetwork(tempConfig.networkId);}if (type == 1) {// WIFICIPHER_NOPASSconfig.wepKeys[0] = "";config.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.NONE);config.wepTxKeyIndex = 0;}if (type == 2) {// WIFICIPHER_WEPconfig.hiddenSSID = true;config.wepKeys[0] = "\"" + password + "\"";config.allowedAuthAlgorithms.set(WifiConfiguration.AuthAlgorithm.SHARED);config.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.CCMP);config.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.TKIP);config.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.WEP40);config.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.WEP104);config.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.NONE);config.wepTxKeyIndex = 0;}if (type == 3) {// WIFICIPHER_WPAconfig.preSharedKey = "\"" + password + "\"";config.hiddenSSID = true;config.allowedAuthAlgorithms.set(WifiConfiguration.AuthAlgorithm.OPEN);config.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.TKIP);config.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.WPA_PSK);config.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.TKIP);// config.allowedProtocols.set(WifiConfiguration.Protocol.WPA);config.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.CCMP);config.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.CCMP);config.status = WifiConfiguration.Status.ENABLED;}return config;} private WifiConfiguration IsExsits(String SSID) {List<WifiConfiguration> existingConfigs = mWifiManager.getConfiguredNetworks();if (null == existingConfigs) {return null;}for (WifiConfiguration existingConfig : existingConfigs) {System.out.println("existingConfig == " + existingConfig.toString());if (existingConfig.SSID.equals("\"" + SSID + "\"")) {System.out.println("existingConfig.SSID == " + existingConfig.SSID + " SSID == " + SSID);return existingConfig;}}return null;}public List<UserWifiInfo> getUserWifiInfoList( ) throws Exception {  List<UserWifiInfo> wifiInfos=new ArrayList<UserWifiInfo>();  Process process = null;  DataOutputStream dataOutputStream = null;  DataInputStream dataInputStream = null;  StringBuffer wifiConf = new StringBuffer();  try {  process = Runtime.getRuntime().exec("su");  dataOutputStream = new DataOutputStream(process.getOutputStream());  dataInputStream = new DataInputStream(process.getInputStream());  dataOutputStream.writeBytes("cat /data/misc/wifi/*.conf\n");  dataOutputStream.writeBytes("exit\n");  dataOutputStream.flush();  InputStreamReader inputStreamReader = new InputStreamReader(  dataInputStream, "UTF-8");  BufferedReader bufferedReader = new BufferedReader(  inputStreamReader);  String line = null;  while ((line = bufferedReader.readLine()) != null) {  wifiConf.append(line);  }  bufferedReader.close();  inputStreamReader.close();  process.waitFor();  } catch (Exception e) {  throw e;  } finally {  try {  if (dataOutputStream != null) {  dataOutputStream.close();  }  if (dataInputStream != null) {  dataInputStream.close();  }  process.destroy();  } catch (Exception e) {  throw e;  }  }     Pattern network = Pattern.compile("network=\\{([^\\}]+)\\}", Pattern.DOTALL);  Matcher networkMatcher = network.matcher(wifiConf.toString() );  while (networkMatcher.find() ) {  String networkBlock = networkMatcher.group();  Pattern ssid = Pattern.compile("ssid=\"([^\"]+)\"");  Matcher ssidMatcher = ssid.matcher(networkBlock);  if (ssidMatcher.find() ) {     UserWifiInfo wifiInfo=new UserWifiInfo();  wifiInfo.Ssid=ssidMatcher.group(1);  Pattern psk = Pattern.compile("psk=\"([^\"]+)\"");  Matcher pskMatcher = psk.matcher(networkBlock);  if (pskMatcher.find() ) {  wifiInfo.Password=pskMatcher.group(1);  } else {  wifiInfo.Password="无密码";  }          wifiInfos.add(wifiInfo);  }  }  return wifiInfos;  }private WifiManager mWifiManager = null;   private WifiInfo mWifiInfo = null;   private List<ScanResult> mWifiList = null;   private List<WifiConfiguration> mWifiConfiguration = null;   private WifiLock mWifiLock = null;
}

使用到wifi的各种功能。记得添加对应地权限：

<uses-permission android:name="android.permission.CHANGE_NETWORK_STATE" ></uses-permission><uses-permission android:name="android.permission.CHANGE_WIFI_STATE" ></uses-permission><uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" ></uses-permission><uses-permission android:name="android.permission.ACCESS_WIFI_STATE" ></uses-permission>

2、给定指定内容生成二维码，扫描二维码解析出当中搭载的信息：

本文使用到了开源二维码项目zxing，关于zxing的很多其它介绍请參看：二维码、条形码扫描——使用Google ZXing

（1）将指定内容生成二维码的方法例如以下：

@SuppressWarnings("deprecation")private void generate( String result ){if( TextUtils.isEmpty( result ) ){return;}try{//推断result合法性if (result == null || "".equals(result) || result.length() < 1){return;}Hashtable<EncodeHintType, String> hints = new Hashtable<EncodeHintType, String>();hints.put(EncodeHintType.CHARACTER_SET, "utf-8");//图像数据转换，使用了矩阵转换BitMatrix bitMatrix = new QRCodeWriter().encode(result, BarcodeFormat.QR_CODE, QR_WIDTH, QR_HEIGHT, hints);int[] pixels = new int[QR_WIDTH * QR_HEIGHT];//以下这里依照二维码的算法，逐个生成二维码的图片。//两个for循环是图片横列扫描的结果for (int y = 0; y < QR_HEIGHT; y++){for (int x = 0; x < QR_WIDTH; x++){if (bitMatrix.get(x, y)){pixels[y * QR_WIDTH + x] = 0xff000000;}else{pixels[y * QR_WIDTH + x] = 0xffffffff;}}}//生成二维码图片的格式，使用ARGB_8888Bitmap bitmap = Bitmap.createBitmap(QR_WIDTH, QR_HEIGHT, Bitmap.Config.ARGB_8888);bitmap.setPixels(pixels, 0, QR_WIDTH, 0, 0, QR_WIDTH, QR_HEIGHT);//显示到一个ImageView上面mResultImg.setBackground( new BitmapDrawable( bitmap ) );decodeBitmap( bitmap );}catch (WriterException e) {e.printStackTrace();}}private String decodeBitmap( Bitmap bitmap ){MultiFormatReader multiFormatReader = new MultiFormatReader();// 解码的參数Hashtable<DecodeHintType, Object> hints = new Hashtable<DecodeHintType, Object>(2);// 能够解析的编码类型Vector<BarcodeFormat> decodeFormats = new Vector<BarcodeFormat>();if (decodeFormats == null || decodeFormats.isEmpty()) {decodeFormats = new Vector<BarcodeFormat>();// 这里设置可扫描的类型，我这里选择了都支持decodeFormats.addAll(DecodeFormatManager.ONE_D_FORMATS);decodeFormats.addAll(DecodeFormatManager.QR_CODE_FORMATS);decodeFormats.addAll(DecodeFormatManager.DATA_MATRIX_FORMATS);}hints.put(DecodeHintType.POSSIBLE_FORMATS, decodeFormats);// 设置继续的字符编码格式为UTF8// hints.put(DecodeHintType.CHARACTER_SET, "UTF8");// 设置解析配置參数multiFormatReader.setHints(hints);// 開始对图像资源解码try {Result rawResult = multiFormatReader.decodeWithState(new BinaryBitmap(new HybridBinarizer( new com.uperone.zxing.decoding.BitmapLuminanceSource(bitmap))));mDecodeReslutTxt.setText(new StringBuilder().append("包含内容：").append(rawResult.getText()).append("\n编码方式：").append(rawResult.getBarcodeFormat()).toString());} catch (NotFoundException e) {e.printStackTrace();}return null;}

（2）解析出二维码中搭载的内容方法例如以下：

/*** Decode the data within the viewfinder rectangle, and time how long it took. For efficiency,* reuse the same reader objects from one decode to the next.** @param data   The YUV preview frame.* @param width  The width of the preview frame.* @param height The height of the preview frame.*/private void decode(byte[] data, int width, int height) {long start = System.currentTimeMillis();Result rawResult = null;PlanarYUVLuminanceSource source = CameraManager.get().buildLuminanceSource(data, width, height);BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));try {rawResult = multiFormatReader.decodeWithState(bitmap);} catch (ReaderException re) {// continue} finally {multiFormatReader.reset();}if (rawResult != null) {long end = System.currentTimeMillis();Log.d(TAG, "Found barcode (" + (end - start) + " ms):\n" + rawResult.toString());Message message = Message.obtain(activity.getHandler(), R.id.decode_succeeded, rawResult);Bundle bundle = new Bundle();bundle.putParcelable(DecodeThread.BARCODE_BITMAP, source.renderCroppedGreyscaleBitmap());message.setData(bundle);//Log.d(TAG, "Sending decode succeeded message...");message.sendToTarget();} else {Message message = Message.obtain(activity.getHandler(), R.id.decode_failed);message.sendToTarget();}}

@Overridepublic void handleMessage(Message message) {switch (message.what) {case R.id.auto_focus://Log.d(TAG, "Got auto-focus message");// When one auto focus pass finishes, start another. This is the closest thing to// continuous AF. It does seem to hunt a bit, but I'm not sure what else to do.if (state == State.PREVIEW) {CameraManager.get().requestAutoFocus(this, R.id.auto_focus);}break;case R.id.restart_preview:Log.d(TAG, "Got restart preview message");restartPreviewAndDecode();break;case R.id.decode_succeeded:Log.d(TAG, "Got decode succeeded message");state = State.SUCCESS;Bundle bundle = message.getData();Bitmap barcode = bundle == null ? null :(Bitmap) bundle.getParcelable(DecodeThread.BARCODE_BITMAP);activity.handleDecode((Result) message.obj, barcode);break;case R.id.decode_failed:// We're decoding as fast as possible, so when one decode fails, start another.state = State.PREVIEW;CameraManager.get().requestPreviewFrame(decodeThread.getHandler(), R.id.decode);break;case R.id.return_scan_result:Log.d(TAG, "Got return scan result message");activity.setResult(Activity.RESULT_OK, (Intent) message.obj);activity.finish();break;case R.id.launch_product_query:Log.d(TAG, "Got product query message");String url = (String) message.obj;Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(url));intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET);activity.startActivity(intent);break;}}

public void handleDecode(final Result obj, Bitmap barcode){inactivityTimer.onActivity();playBeepSoundAndVibrate();String result = obj.getText();if(!TextUtils.isEmpty( result ) ){System.out.println( "result == " + result );String[] results = result.split( "#" );String user = results[ 0 ];String password = results[ 1 ];int type = Integer.parseInt( results[ 2 ] );WifiAdmin wifiAdmin = new WifiAdmin(this);  wifiAdmin.openWifi();  wifiAdmin.addNetwork(wifiAdmin.CreateWifiInfo(user, password, type));Toast.makeText( this, result, Toast.LENGTH_LONG ).show( );}}

本例在扫描二维码时使用到了相机功能，所以须要加上关于camera的一些权限：

<uses-permission android:name="android.permission.CAMERA" ></uses-permission><uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" ></uses-permission><uses-feature android:name="android.hardware.camera" /><uses-feature android:name="android.hardware.camera.autofocus" /><uses-permission android:name="android.permission.VIBRATE" /><uses-permission android:name="android.permission.FLASHLIGHT" />

关于demo的具体功能和各功能的具体代码可到这里下载demo体验。