java - 如果已经连接到另一个 WiFi，则连接到特定 WiFi

Question

这两天我一直在苦苦挣扎，我找不到解决办法。我尝试了这段代码，但随着时间的推移，它在 Android 5(Lollipop) 上运行，但在 7.1.1.(Nougat) 上不起作用。我有另一个场景，手机失去连接，之后，它需要返回到旧 Wifi。

public void setWifiConnection1(View view){
  WifiManager wifiManager = (WifiManager) getApplicationContext().getSystemService(Context.WIFI_SERVICE);


  WifiConfiguration wc = new WifiConfiguration();
    WifiInfo wifiInfo = wifiManager.getConnectionInfo();

  wc.SSID = "\"NETWORK_NAME\"";
  wc.preSharedKey = "\"PASSWORD\"";
    wc.status = WifiConfiguration.Status.ENABLED;
    wc.allowedProtocols.set(WifiConfiguration.Protocol.RSN);
    wc.allowedProtocols.set(WifiConfiguration.Protocol.WPA);
    wc.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.WPA_PSK);
    wc.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.CCMP);
    wc.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.TKIP);
    wc.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.WEP40);
    wc.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.WEP104);
    wc.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.CCMP);
    wc.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.TKIP);
    wc.priority = 999999;
    wifiManager.setWifiEnabled(true);
    int netId = wifiManager.addNetwork(wc);
    if (netId == -1) {
        netId = getExistingNetworkId(wc.SSID);
    }
    wifiManager.disconnect();
    wifiManager.enableNetwork(netId, true);
    wifiManager.reconnect(); 
}

 private int getExistingNetworkId(String SSID) {

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

    List<WifiConfiguration> configuredNetworks = wifiManager.getConfiguredNetworks();
    if (configuredNetworks != null) {
        for (WifiConfiguration existingConfig : configuredNetworks) {
            if (existingConfig.SSID.equals(SSID)) {
                return existingConfig.networkId;
            }
        }
    }
    return -1;
}

Answer 1

wifiManager.setWifiEnabled(true);

您不能在该行之后立即执行您的代码。您应该执行 wifiManager.isWifiEnabled() 检查并订阅广播(如果它被禁用)。

下一步...

wifiManager.disconnect();
wifiManager.enableNetwork(netId, true);
wifiManager.reconnect();

这部分很奇怪:你为什么断开连接？请注意，大多数 WifiManager 操作都是异步的，因此您每次都会观察到不同的结果 - 真正的“断开连接”可能会在您尝试启用所需网络后发生。

你总能从系统API中获得灵感:https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r30/wifi/java/android/net/wifi/WifiManager.java#2773

所以正确的顺序是:

wifiManager.addNetwork(...);
wifiManager.enableNetwork(netId, true);
wifiManager.saveConfiguration();
wifiManager.reconnect();

但如果允许的话，直接使用系统API会更方便。