如果你的设备知道Wifi配置(已经存储)，我们可以跳过火箭科学。只需循环配置，检查SSID是否匹配。如果是，连接并返回。

设置权限:

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

连接:

    try {
    String ssid = null;
    if (wifi == Wifi.PCAN_WIRELESS_GATEWAY) {
        ssid = AesPrefs.get(AesConst.PCAN_WIRELESS_SSID,
                context.getString(R.string.pcan_wireless_ssid_default));
    } else if (wifi == Wifi.KJ_WIFI) {
        ssid = context.getString(R.string.remote_wifi_ssid_default);
    }

    WifiManager wifiManager = (WifiManager) context.getApplicationContext()
            .getSystemService(Context.WIFI_SERVICE);

    List<WifiConfiguration> wifiConfigurations = wifiManager.getConfiguredNetworks();

    for (WifiConfiguration wifiConfiguration : wifiConfigurations) {
        if (wifiConfiguration.SSID.equals("\"" + ssid + "\"")) {
            wifiManager.enableNetwork(wifiConfiguration.networkId, true);
            Log.i(TAG, "connectToWifi: will enable " + wifiConfiguration.SSID);
            wifiManager.reconnect();
            return null; // return! (sometimes logcat showed me network-entries twice,
            // which may will end in bugs)
        }
    }
} catch (NullPointerException | IllegalStateException e) {
    Log.e(TAG, "connectToWifi: Missing network configuration.");
}
return null;

在连接WIFI网络之前，您需要检查WIFI网络的安全类型ScanResult类有一个功能。该字段提供网络类型

参考:https://developer.android.com/reference/android/net/wifi/ScanResult.html功能

有三种类型的WIFI网络。

首先，实例化一个wificconfiguration对象并填写网络的SSID(注意它必须用双引号括起来)，将初始状态设置为禁用，并指定网络的优先级(40左右的数字似乎工作得很好)。

WifiConfiguration wfc = new WifiConfiguration();

wfc.SSID = "\"".concat(ssid).concat("\"");
wfc.status = WifiConfiguration.Status.DISABLED;
wfc.priority = 40;

现在是更复杂的部分:我们需要填充wiificconfiguration的几个成员来指定网络的安全模式。 对于开放网络。

wfc.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.NONE);
wfc.allowedProtocols.set(WifiConfiguration.Protocol.RSN);
wfc.allowedProtocols.set(WifiConfiguration.Protocol.WPA);
wfc.allowedAuthAlgorithms.clear();
wfc.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.CCMP);
wfc.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.TKIP);
wfc.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.WEP40);
wfc.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.WEP104);
wfc.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.CCMP);
wfc.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.TKIP);

对于使用WEP的网络;注意WEP密钥也包含在双引号中。

wfc.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.NONE);
wfc.allowedProtocols.set(WifiConfiguration.Protocol.RSN);
wfc.allowedProtocols.set(WifiConfiguration.Protocol.WPA);
wfc.allowedAuthAlgorithms.set(WifiConfiguration.AuthAlgorithm.OPEN);
wfc.allowedAuthAlgorithms.set(WifiConfiguration.AuthAlgorithm.SHARED);
wfc.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.CCMP);
wfc.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.TKIP);
wfc.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.WEP40);
wfc.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.WEP104);

if (isHexString(password)) wfc.wepKeys[0] = password;
else wfc.wepKeys[0] = "\"".concat(password).concat("\"");
wfc.wepTxKeyIndex = 0;

对于使用WPA和WPA2的网络，我们可以为其中任何一个设置相同的值。

wfc.allowedProtocols.set(WifiConfiguration.Protocol.RSN);
wfc.allowedProtocols.set(WifiConfiguration.Protocol.WPA);
wfc.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.WPA_PSK);
wfc.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.CCMP);
wfc.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.TKIP);
wfc.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.WEP40);
wfc.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.WEP104);
wfc.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.CCMP);
wfc.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.TKIP);

wfc.preSharedKey = "\"".concat(password).concat("\"");

最后，我们可以将该网络添加到WifiManager的已知列表中

WifiManager wfMgr = (WifiManager) context.getSystemService(Context.WIFI_SERVICE);
int networkId = wfMgr.addNetwork(wfc);
if (networkId != -1) {
 // success, can call wfMgr.enableNetwork(networkId, true) to connect
} 

我也试着连接到网络。 以上提出的解决方案都不适用于hugerock t70。 wifiManager.disconnect()函数;不断开当前网络。 Аnd因此不能重新连接到指定的网络。 我修改了上面的代码。 对我来说，代码bolow工作完美:

String networkSSID = "test";
String networkPass = "pass";

WifiConfiguration conf = new WifiConfiguration();
conf.SSID = "\"" + networkSSID + "\"";   
conf.wepKeys[0] = "\"" + networkPass + "\""; 
conf.wepTxKeyIndex = 0;
conf.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.NONE);
conf.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.WEP40); 
conf.preSharedKey = "\""+ networkPass +"\"";

WifiManager wifiManager =         
(WifiManager)context.getSystemService(Context.WIFI_SERVICE);    

int networkId = wifiManager.addNetwork(conf);
wifi_inf = wifiManager.getConnectionInfo();

/////important!!!
wifiManager.disableNetwork(wifi_inf.getNetworkId());
/////////////////

wifiManager.enableNetwork(networkId, true);

这是一个你可以子类化的活动，以强制连接到特定的wifi: https://github.com/zoltanersek/android-wifi-activity/blob/master/app/src/main/java/com/zoltanersek/androidwifiactivity/WifiActivity.java

你需要子类化这个活动并实现它的方法:

public class SampleActivity extends WifiBaseActivity {
  @Override
  protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
  }

  @Override
  protected int getSecondsTimeout() {
      return 10;
  }

  @Override
  protected String getWifiSSID() {
      return "WifiNetwork";
  }

  @Override
  protected String getWifiPass() {
      return "123456";
  }
}

在API级别29中，WifiManager.enableNetwork()方法已弃用。根据Android API文档(点击这里查看):

请参阅WifiNetworkSpecifier.Builder#build()了解触发连接到Wi-Fi网络的新机制。 参见addnetworkrecommendations (java.util.List)， removenetworkrecommendations (java.util.List)获取添加Wi-Fi的新API 当自动连接到wifi时，考虑网络。兼容性 注意:对于以Build.VERSION_CODES为目标的应用程序。Q或以上，这个 API总是返回false。

从API级别29开始，要连接到WiFi网络，您将需要使用WifiNetworkSpecifier。您可以在https://developer.android.com/reference/android/net/wifi/WifiNetworkSpecifier.Builder.html#build(上找到示例代码)

我绞尽脑汁才明白为什么你的WPA/WPA2答案不管用……经过几个小时的尝试，我找到了你所缺少的:

conf.allowedAuthAlgorithms.set(WifiConfiguration.AuthAlgorithm.OPEN);

需要WPA网络!!!!

现在，它工作了:)