Android 扫描WiFi，连接WiFi¶

win7
Android Studio 3.0.1

概述¶

在Android应用中扫描WiFi热点。并把搜索到的WiFi热点信息显示出来。
连接、切换到指定的WiFi。

申请权限¶

申请网络和WiFi相关的权限

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

需要动态申请定位权限，否则获取不到WiFi的搜索结果

WiFi信息扫描¶

使用WifiManager.startScan()方法开始搜索WiFi信息。收取广播WifiManager.SCAN_RESULTS_AVAILABLE_ACTION获得搜索结果。搜索结果是ScanResult类。

private WifiManager mWifiManager;

// 在Fragment中获取WifiManager
mWifiManager = (WifiManager) getActivity().getApplication().getApplicationContext().getSystemService(Context.WIFI_SERVICE);

// 启动搜索
if (!mWifiManager.isWifiEnabled()) {
    mWifiManager.setWifiEnabled(true);
}
mWifiManager.startScan();

注册广播，获取WiFi搜索结果

    private BroadcastReceiver mBroadcastReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();
            if (WifiManager.SCAN_RESULTS_AVAILABLE_ACTION.equals(action)) {
                List<ScanResult> scanResults = mWifiManager.getScanResults();
                // 获取到结果后进行其他操作...
            }
        }
    };

将WiFi搜索结果显示出来¶

使用RecyclerView显示搜索到的结果。提供选择功能。

   public                                                                                                                         //

href="#__codelineno-3-1">/** * WiFi搜索 * Created by Rust on 2018/5/18. */ class="w"> class WiFiScanFragment extends Fragment { private static final String TAG = "WiFiScanFragment"; public static final String F_TAG = "f_tag_WiFiScanFragment"; private View mTipLayout; private Button mRefreshWiFiBtn; private EditText mWiFiPrefixEt; private String mWiFiPrefix = ""; private WifiManager mWifiManager; private WiFiReAdapter mWiFiReAdapter; private TextView mChosenInfoTv; public static WiFiScanFragment newFrag() { return new WiFiScanFragment(); } @Override public void onCreate(@Nullable Bundle savedInstanceState) { super.onCreate(savedInstanceState); mWifiManager = (WifiManager) getActivity().getApplication().getApplicationContext().getSystemService(Context.WIFI_SERVICE); getActivity().registerReceiver(mBroadcastReceiver, new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION)); Log.d(TAG, "onCreate: 注册广播"); } @Nullable @Override public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, Bundle savedInstanceState) { return inflater.inflate(R.layout.frag_numbers_upgrade, container, false); } @Override public void onViewCreated(View view, @Nullable Bundle savedInstanceState) { super.onViewCreated(view, savedInstanceState); mTipLayout = view.findViewById(R.id.tip_layout); mRefreshWiFiBtn = view.findViewById(R.id.refresh_wifi_btn); mWiFiPrefixEt = view.findViewById(R.id.wifi_prefix_et); mChosenInfoTv = view.findViewById(R.id.chosen_info_tv); view.findViewById(R.id.top_back_iv).setOnClickListener(mOnClickListener); view.findViewById(R.id.top_end_iv).setOnClickListener(mOnClickListener); view.findViewById(R.id.choose_all_btn).setOnClickListener(mOnClickListener); view.findViewById(R.id.choose_none_btn).setOnClickListener(mOnClickListener); view.findViewById(R.id.choose_revert_btn).setOnClickListener(mOnClickListener); mRefreshWiFiBtn.setOnClickListener(mOnClickListener); RecyclerView wifiRv = view.findViewById(R.id.wifi_rv); mWiFiReAdapter = new WiFiReAdapter(); wifiRv.setAdapter(mWiFiReAdapter); wifiRv.setLayoutManager(new GridLayoutManager(getActivity(), 3)); mWiFiReAdapter.setOnItemClickListener(mOnItemClickListener); mWiFiPrefixEt.addTextChangedListener(new TextWatcher() { @Override public void beforeTextChanged(CharSequence s, int start, int count, int after) { } @Override public void onTextChanged(CharSequence s, int start, int before, int count) { } @Override public void afterTextChanged(Editable s) { mWiFiPrefix = s.toString(); } }); } @Override public void onDestroy() { super.onDestroy(); getActivity().unregisterReceiver(mBroadcastReceiver); Log.d(TAG, "onDestroy: 销毁广播"); } private View.OnClickListener mOnClickListener = new View.OnClickListener() { @Override public void onClick(View v) { switch (v.getId()) { case R.id.top_back_iv: getActivity().finish(); break; case R.id.top_end_iv: if (mTipLayout.getVisibility() != View.VISIBLE) { mTipLayout.setVisibility(View.VISIBLE); } else { mTipLayout.setVisibility(View.GONE); } break; case R.id.refresh_wifi_btn: if (!mWifiManager.isWifiEnabled()) { mWifiManager.setWifiEnabled(true); } mWifiManager.startScan(); mRefreshWiFiBtn.setText("扫描中.."); ToastUtil.showShort(getActivity(), "开始扫描"); break; case R.id.choose_all_btn: mWiFiReAdapter.chooseAll(); updateChosenNoteUI(); break; case R.id.choose_none_btn: mWiFiReAdapter.chooseNone(); updateChosenNoteUI(); break; case R.id.choose_revert_btn: mWiFiReAdapter.chooseRevert(); updateChosenNoteUI(); break; } } }; private BroadcastReceiver mBroadcastReceiver = new BroadcastReceiver() { @Override public void onReceive(Context context, Intent intent) { String action = intent.getAction(); if (WifiManager.SCAN_RESULTS_AVAILABLE_ACTION.equals(action)) { List<ScanResult> scanResults = mWifiManager.getScanResults(); mWiFiReAdapter.clearList(); String lowerPrefix = mWiFiPrefix.toLowerCase(); ToastUtil.showShort(getActivity(), "扫描结束"); mRefreshWiFiBtn.setText("刷新"); for (ScanResult s : scanResults) { Log.d(TAG, "onReceive: " + s); if (!TextUtils.isEmpty(s.SSID) && s.SSID.toLowerCase().startsWith(lowerPrefix)) { mWiFiReAdapter.addOrUpdateWiFiScanResult(s); } } mWiFiReAdapter.notifyDataSetChanged(); updateChosenNoteUI(); } } }; public void updateChosenNoteUI() { mChosenInfoTv.setText(String.format(Locale.CHINA, "已选:%d", mWiFiReAdapter.getChosenWiFi().size())); } private WiFiAdapterOnItemClickListener mOnItemClickListener = new WiFiAdapterOnItemClickListener() { @Override public void onItemClick(int pos) { mWiFiReAdapter.revertChosen(pos); updateChosenNoteUI(); } }; private class WiFiReAdapter extends RecyclerView.Adapter<WVH> { private WiFiAdapterOnItemClickListener onItemClickListener; private List<WiFiItem> wifiList; WiFiReAdapter() { wifiList = new ArrayList<>(20); } void setOnItemClickListener(WiFiAdapterOnItemClickListener listener) { this.onItemClickListener = listener; } void clearList() { wifiList.clear(); } void addOrUpdateWiFiScanResult(ScanResult scanResult) { boolean has = false; for (WiFiItem item : wifiList) { if (item.scanResult.SSID.equals(scanResult.SSID)) { has = true; item.scanResult = scanResult; } } if (!has) { wifiList.add(new WiFiItem(scanResult)); } } void chooseAll() { for (WiFiItem i : wifiList) { i.chosen = true; } notifyDataSetChanged(); } void chooseNone() { for (WiFiItem i : wifiList) { i.chosen = false; } notifyDataSetChanged(); } void chooseRevert() { for (WiFiItem i : wifiList) { i.chosen = !i.chosen; } notifyDataSetChanged(); } void revertChosen(final int pos) { WiFiItem item = wifiList.get(pos); item.chosen = !item.chosen; notifyItemChanged(pos); } List<ScanResult> getChosenWiFi() { List<ScanResult> res = new ArrayList<>(); for (WiFiItem item : wifiList) { if (item.chosen) { res.add(item.scanResult); } } return res; } @Override public WVH onCreateViewHolder(ViewGroup parent, int viewType) { return new WVH(LayoutInflater.from(parent.getContext()).inflate(R.layout.item_wifi, parent, false)); } @Override public void onBindViewHolder(WVH holder, final int position) { final int pos = position; WiFiItem item = wifiList.get(pos); holder.ssidTv.setText(item.scanResult.SSID); holder.chosenCb.setChecked(item.chosen); holder.itemRoot.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { if (null != onItemClickListener) { onItemClickListener.onItemClick(pos); } } }); } @Override public int getItemCount() { return wifiList.size(); } } static class WiFiItem { boolean chosen = false; ScanResult scanResult; WiFiItem(ScanResult s) { scanResult = s; } } static class WVH extends RecyclerView.ViewHolder { View itemRoot; CheckBox chosenCb; TextView ssidTv; TextView noteTv; WVH(View itemView) { super(itemView); itemRoot = itemView; chosenCb = itemView.findViewById(R.id.chosen_cb); ssidTv = itemView.findViewById(R.id.ssid_tv); noteTv = itemView.findViewById(R.id.note_tv); } } public interface WiFiAdapterOnItemClickListener { void onItemClick(final int pos); } }

连接WiFi¶

创建连接WiFi的帮助类；连接WiFi需要WifiManager

检查目标SSID是否已经被保存

    private static WifiConfiguration getExistsCfg(String SSID, final WifiManager wifiManager) {
        List<WifiConfiguration> existingConfigs = wifiManager.getConfiguredNetworks();
        for (WifiConfiguration existingConfig : existingConfigs) {
            if (existingConfig.SSID.equals("\"" + SSID + "\"")) {
                return existingConfig;
            }
        }
        return null;
    }

创建wpa加密的WiFi配置，接下来连接到这个WiFi需要这些信息

    private static WifiConfiguration createWpaWifiInfo(String SSID, String password) {
        WifiConfiguration config = new WifiConfiguration();
        config.allowedAuthAlgorithms.clear();
        config.allowedGroupCiphers.clear();
        config.allowedKeyManagement.clear();
        config.allowedPairwiseCiphers.clear();
        config.allowedProtocols.clear();
        config.SSID = "\"" + SSID + "\"";
        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);
        // 此处需要修改否则不能自动重联
        // 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;
    }

连接到指定WiFiWifiConfiguration；如果wifiManager.addNetwork返回值是-1，表示操作失败

如果切换WiFi成功，会在广播中收到WifiManager.NETWORK_STATE_CHANGED_ACTION

    private static void connectToWiFi(WifiConfiguration config, final WifiManager wifiManager) {
        int wcgID = wifiManager.addNetwork(config);
        android.util.Log.d(TAG, LOG_PRE + "connectToWiFi: " + config.SSID + ";  res==" + wcgID);
        if (wcgID == -1) {
            android.util.Log.d(TAG, LOG_PRE + "操作失败");
        }
        boolean enRes = wifiManager.enableNetwork(wcgID, true);
        Log.d(TAG, LOG_PRE + "切换到WiFi: " + config.SSID + "; enable " + enRes);
    }

操作WiFi时，就像操作蓝牙一样，可能会需要自定义一些延时，给系统调用硬件设备一些时间。

public class NUHelper {
    private static final String TAG = "NU";
    private static final String LOG_PRE = "Helper - ";
    private static final String DEF_WIFI_PWD = "88888888";
    public static int mSwitchWiFiWaitMM = 3000; // 切换WiFi时等待的最小时间

    /**
     * 当前正在处理的WiFi
     */
    public static String mCurrSSID = ""; // 没有双引号包围

    /**
     * 连接等待池中的下一个WiFi
     */
    public synchronized static void connectToNext(final ScanResult scanResult, final WifiManager wifiManager) {
        mCurrSSID = scanResult.SSID;
        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    Thread.sleep(mSwitchWiFiWaitMM); // 等待WiFi操作
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                android.util.Log.d(TAG, LOG_PRE + "开始处理 " + mCurrSSID);
                WifiInfo wifiInfo = wifiManager.getConnectionInfo();
                android.util.Log.d(TAG, LOG_PRE + "当前WiFi: " + wifiInfo.getSSID());
                if (wifiInfo.getSSID().equals("\"" + mCurrSSID + "\"")) {
                    android.util.Log.d(TAG, LOG_PRE + "是当前连接的WiFi " + mCurrSSID);
                    // 当前已经连接上了这个目标WiFi
                } else {
                    WifiConfiguration cfg = getExistsCfg(mCurrSSID, wifiManager);
                    if (null == cfg) {
                        android.util.Log.d(TAG, LOG_PRE + "没有连接过这个WiFi - " + mCurrSSID);
                        cfg = createWpaWifiInfo(mCurrSSID, DEF_WIFI_PWD);
                    } else {
                        android.util.Log.d(TAG, LOG_PRE + "之前连接过这个WiFi - " + mCurrSSID);
                    }
                    connectToWiFi(cfg, wifiManager);
                }
            }
        }).start();
    }
}

参考资料¶

Android - ScanResult

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