主界面，搜索附近WIFI信息

/**
 * Search WIFI and show in ListView
 * 
 */
public class MainActivity extends Activity implements OnClickListener,
        OnItemClickListener {
    private Button search_btn;
    private ListView wifi_lv;
    private WifiUtils mUtils;
    private List<String> result;
    private ProgressDialog progressdlg = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mUtils = new WifiUtils(this);
        findViews();
        setLiteners();
    }

    private void findViews() {
        this.search_btn = (Button) findViewById(R.id.search_btn);
        this.wifi_lv = (ListView) findViewById(R.id.wifi_lv);
    }

    private void setLiteners() {
        search_btn.setOnClickListener(this);
        wifi_lv.setOnItemClickListener(this);
    }

    @Override
    public void onClick(View v) {
        if (v.getId() == R.id.search_btn) {
            showDialog();
            new MyAsyncTask().execute();
        }
    }

    /**
     * init dialog and show
     */
    private void showDialog() {
        progressdlg = new ProgressDialog(this);
        progressdlg.setCanceledOnTouchOutside(false);
        progressdlg.setCancelable(false);
        progressdlg.setProgressStyle(ProgressDialog.STYLE_SPINNER);
        progressdlg.setMessage(getString(R.string.wait_moment));
        progressdlg.show();
    }

    /**
     * dismiss dialog
     */
    private void progressDismiss() {
        if (progressdlg != null) {
            progressdlg.dismiss();
        }
    }

    class MyAsyncTask extends AsyncTask<Void, Void, Void> {

        @Override
        protected Void doInBackground(Void... arg0) {
            //扫描附近WIFI信息
            result = mUtils.getScanWifiResult();
            return null;
        }

        @Override
        protected void onPostExecute(Void result) {
            super.onPostExecute(result);
            progressDismiss();
            initListViewData();
        }
    }

    private void initListViewData() {
        if (null != result && result.size() > 0) {
            wifi_lv.setAdapter(new ArrayAdapter<String>(
                    getApplicationContext(), R.layout.wifi_list_item,
                    R.id.ssid, result));
        } else {
            wifi_lv.setEmptyView(findViewById(R.layout.list_empty));
        }
    }

    @Override
    public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
        TextView tv = (TextView) arg1.findViewById(R.id.ssid);
        if (!TextUtils.isEmpty(tv.getText().toString())) {
            Intent in = new Intent(MainActivity.this, WifiConnectActivity.class);
            in.putExtra("ssid", tv.getText().toString());
            startActivity(in);
        }
    }
}

/**
 * 连接指定的WIFI
 *
 */
public class WifiConnectActivity extends Activity implements OnClickListener {
    private Button connect_btn;
    private TextView wifi_ssid_tv;
    private EditText wifi_pwd_tv;
    private WifiUtils mUtils;
    // wifi之ssid
    private String ssid;
    private String pwd;
    private ProgressDialog progressdlg = null;
    @SuppressLint("HandlerLeak")
    private Handler mHandler = new Handler() {
        public void handleMessage(android.os.Message msg) {
            switch (msg.what) {
            case 0:
                showToast("WIFI连接成功");
                finish();
                break;
            case 1:
                showToast("WIFI连接失败");
                break;

            }
            progressDismiss();
        }
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_connect);
        mUtils = new WifiUtils(this);
        findViews();
        setLiteners();
        initDatas();
    }

    /**
     * init dialog
     */
    private void progressDialog() {
        progressdlg = new ProgressDialog(this);
        progressdlg.setCanceledOnTouchOutside(false);
        progressdlg.setCancelable(false);
        progressdlg.setProgressStyle(ProgressDialog.STYLE_SPINNER);
        progressdlg.setMessage(getString(R.string.wait_moment));
        progressdlg.show();
    }

    /**
     * dissmiss dialog
     */
    private void progressDismiss() {
        if (progressdlg != null) {
            progressdlg.dismiss();
        }
    }

    private void initDatas() {
        ssid = getIntent().getStringExtra("ssid");
        if (!TextUtils.isEmpty(ssid)) {
            ssid = ssid.replace("\"", "");
        }
        this.wifi_ssid_tv.setText(ssid);
    }

    private void findViews() {
        this.connect_btn = (Button) findViewById(R.id.connect_btn);
        this.wifi_ssid_tv = (TextView) findViewById(R.id.wifi_ssid_tv);
        this.wifi_pwd_tv = (EditText) findViewById(R.id.wifi_pwd_tv);
    }

    private void setLiteners() {
        connect_btn.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        if (v.getId() == R.id.connect_btn) {// 下一步操作
            pwd = wifi_pwd_tv.getText().toString();
            // 判断密码输入情况
            if (TextUtils.isEmpty(pwd)) {
                Toast.makeText(this, "请输入wifi密码", Toast.LENGTH_SHORT).show();
                return;
            }
            progressDialog();
            // 在子线程中处理各种业务
            dealWithConnect(ssid, pwd);
        }
    }

    private void dealWithConnect(final String ssid, final String pwd) {
        new Thread(new Runnable() {
            @Override
            public void run() {
                Looper.prepare();
                // 检验密码输入是否正确
                boolean pwdSucess = mUtils.connectWifiTest(ssid, pwd);
                try {
                    Thread.sleep(4000);
                } catch (Exception e) {
                    e.printStackTrace();
                }
                if (pwdSucess) {
                    mHandler.sendEmptyMessage(0);
                } else {
                    mHandler.sendEmptyMessage(1);
                }
            }
        }).start();
    }

    private void showToast(String str) {
        Toast.makeText(WifiConnectActivity.this, str, Toast.LENGTH_SHORT).show();
    }
}

工具类：

public class WifiUtils {
    // 上下文Context对象
    private Context mContext;
    // WifiManager对象
    private WifiManager mWifiManager;

    public WifiUtils(Context mContext) {
        this.mContext = mContext;
        mWifiManager = (WifiManager) mContext
                .getSystemService(Context.WIFI_SERVICE);
    }

    /**
     * 判断手机是否连接在Wifi上
     */
    public boolean isConnectWifi() {
        // 获取ConnectivityManager对象
        ConnectivityManager conMgr = (ConnectivityManager) mContext
                .getSystemService(Context.CONNECTIVITY_SERVICE);
        // 获取NetworkInfo对象
        NetworkInfo info = conMgr.getActiveNetworkInfo();
        // 获取连接的方式为wifi
        State wifi = conMgr.getNetworkInfo(ConnectivityManager.TYPE_WIFI)
                .getState();

        if (info != null && info.isAvailable() && wifi == State.CONNECTED)

        {
            return true;
        } else {
            return false;
        }

    }

    /**
     * 获取当前手机所连接的wifi信息
     */
    public WifiInfo getCurrentWifiInfo() {
        return mWifiManager.getConnectionInfo();
    }

    /**
     * 添加一个网络并连接 传入参数：WIFI发生配置类WifiConfiguration
     */
    public boolean addNetwork(WifiConfiguration wcg) {
        int wcgID = mWifiManager.addNetwork(wcg);
        return mWifiManager.enableNetwork(wcgID, true);
    }

    /**
     * 搜索附近的热点信息，并返回所有热点为信息的SSID集合数据
     */
    public List<String> getScanWifiResult() {
        // 扫描的热点数据
        List<ScanResult> resultList;
        // 开始扫描热点
        mWifiManager.startScan();
        resultList = mWifiManager.getScanResults();
        ArrayList<String> ssids = new ArrayList<String>();
        if (resultList != null) {
            for (ScanResult scan : resultList) {
                ssids.add(scan.SSID);// 遍历数据，取得ssid数据集
            }
        }
        return ssids;
    }

    /**
     * 连接wifi 参数：wifi的ssid及wifi的密码
     */
    public boolean connectWifiTest(final String ssid, final String pwd) {
        boolean isSuccess = false;
        boolean flag = false;
        mWifiManager.disconnect();
        boolean addSucess = addNetwork(CreateWifiInfo(ssid, pwd, 3));
        if (addSucess) {
            while (!flag && !isSuccess) {
                try {
                    Thread.sleep(10000);
                } catch (InterruptedException e1) {
                    e1.printStackTrace();
                }
                String currSSID = getCurrentWifiInfo().getSSID();
                if (currSSID != null)
                    currSSID = currSSID.replace("\"", "");
                int currIp = getCurrentWifiInfo().getIpAddress();
                if (currSSID != null && currSSID.equals(ssid) && currIp != 0) {
                    isSuccess = true;
                } else {
                    flag = true;
                }
            }
        }
        return isSuccess;

    }

    /**
     * 创建WifiConfiguration对象 分为三种情况：1没有密码;2用wep加密;3用wpa加密
     * 
     * @param SSID
     * @param Password
     * @param Type
     * @return
     */
    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_NOPASS
        {
            config.wepKeys[0] = "";
            config.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.NONE);
            config.wepTxKeyIndex = 0;
        }
        if (Type == 2) // WIFICIPHER_WEP
        {
            config.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_WPA
        {
            config.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();
        for (WifiConfiguration existingConfig : existingConfigs) {
            if (existingConfig.SSID.equals("\"" + SSID + "\"")) {
                return existingConfig;
            }
        }
        return null;
    }

}

—–相关布局文件————–
主页面

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <Button
        android:id="@+id/search_btn"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="10dp"
        android:text="搜索附近WIFI"
        android:textSize="16sp" >
    </Button>

    <ListView
        android:id="@+id/wifi_lv"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/search_btn"
        android:layout_marginTop="10dp"
        android:divider="#d1d1d1"
        android:dividerHeight="1px"
        android:scrollbars="none" >
    </ListView>

</RelativeLayout>

连接页面

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <TextView
        android:id="@+id/wifi_ssid"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="15dp"
        android:padding="10dp"
        android:text="@string/wifi_ssid"
        android:textSize="16sp" />

    <TextView
        android:id="@+id/wifi_ssid_tv"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="15dp"
        android:layout_toRightOf="@id/wifi_ssid"
        android:padding="10dp"
        android:textSize="16sp" />

    <TextView
        android:id="@+id/wifi_pwd"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/wifi_ssid"
        android:layout_marginTop="15dp"
        android:padding="10dp"
        android:text="@string/wifi_pwd"
        android:textSize="16sp" />

    <EditText
        android:id="@+id/wifi_pwd_tv"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/wifi_ssid_tv"
        android:layout_marginRight="15dp"
        android:layout_marginTop="15dp"
        android:layout_toRightOf="@id/wifi_pwd"
        android:hint="@string/input_pwd_hint"
        android:padding="10dp"
        android:textSize="16sp" />

    <Button
        android:id="@+id/connect_btn"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_margin="10dp"
        android:text="连接WIFI"
        android:textSize="16sp" >
    </Button>

</RelativeLayout>

主页面ListView的item

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="40dp"
    android:background="#FFFFFF" >

    <TextView
        android:id="@+id/ssid"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_centerInParent="true"
        android:paddingLeft="15dp"
        android:textColor="#333333"
        android:textSize="16sp" />

</RelativeLayout>

主界面未搜索 到WIFI的展示

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#FFFFFF" >

    <TextView
        android:id="@+id/ssid"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:text="附近暂时没有WIFI"
        android:textColor="#333333"
        android:textSize="16sp" />

</RelativeLayout>

DEMO下载地址：https://github.com/ldm520/WIFI_TOOL