问题描述
我实际上正在编写一些不会让用户访问 android 原生 wifi 连接页面的东西,所以我在我的 Android 应用程序中对其进行了编程。它会扫描可用的 Wifi 网络,将其显示在 ListView 中,然后您单击要连接的网络。
实际上除了我的连接功能之外,一切都运行良好,这使我的应用程序崩溃,所以如果您有任何想法......这里是代码(这是用户进入网络通行证后调用的函数)和堆栈跟踪:
private void connectToNetwork(String networkSSID,String networkPass,String networkCapabilities) {
WifiConfiguration wifiConfig = new WifiConfiguration();
wifiConfig.SSID =networkSSID;
if (networkCapabilities.toupperCase().contains("WEP")) { // WEP Network.
Toast.makeText(this,"WEP Network",Toast.LENGTH_SHORT).show();
wifiConfig.wepKeys[0] = networkPass;
wifiConfig.wepTxKeyIndex = 0;
wifiConfig.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.NONE);
wifiConfig.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.WEP40);
} else if (networkCapabilities.toupperCase().contains("WPA")) { // WPA Network
Toast.makeText(this,"WPA Network",Toast.LENGTH_SHORT).show();
wifiConfig.preSharedKey = networkPass;
} else { // OPEN Network.
Toast.makeText(this,"OPEN Network",Toast.LENGTH_SHORT).show();
wifiConfig.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.NONE);
}
@SuppressLint("MissingPermission")
List<WifiConfiguration> list = this.wifiManager.getConfigurednetworks();
for (WifiConfiguration config : list) {
if (config.SSID != null && config.SSID.equals(networkSSID)) {
this.wifiManager.disconnect();
this.wifiManager.enableNetwork(config.networkId,true);
this.wifiManager.reconnect();
break;
}
}
}
堆栈跟踪:
java.lang.NullPointerException: Attempt to invoke virtual method 'java.util.List android.net.wifi.WifiManager.getConfigurednetworks()' on a null object reference
at solutions.#####.############.WifiActivity.connectToNetwork(WifiActivity.java:148)
解决方法
在@LevM 的帮助下,这里是现在可以工作的完整代码。和一点自我研究。我发布它是因为我没有找到很多解决方案来连接到互联网上的 Android 中的特定 Wifi 网络(SO、Youtube 或其他任何东西),所以如果它可以帮助至少一个开发人员几天,我会很高兴! :D(注意:我是一名学生程序员,我不是说这个解决方案是最好的,但至少它是功能性的)
实际上我的 wifiManager 没有被初始化有问题。然后我删除了 wifiConfiguration 列表循环,我意识到我不需要它。 最后我在 SSID 和密码上添加了字符串格式,因为它们需要在反斜杠(“\”)内。
private boolean connectToNetwork(String networkSSID,String networkPass,String networkCapabilities) {
WifiManager wifiManager = (WifiManager) getApplicationContext().getSystemService(Context.WIFI_SERVICE);
WifiConfiguration wifiConfig = new WifiConfiguration();
wifiConfig.SSID = String.format("\"%s\"",networkSSID);
if (!wifiManager.isWifiEnabled()) {
wifiManager.setWifiEnabled(true);
}
if (networkCapabilities.toUpperCase().contains("WEP")) { // WEP Network.
Toast.makeText(this,"WEP Network",Toast.LENGTH_SHORT).show();
wifiConfig.wepKeys[0] = String.format("\"%s\"",networkPass);
;
wifiConfig.wepTxKeyIndex = 0;
wifiConfig.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.NONE);
wifiConfig.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.WEP40);
} else if (networkCapabilities.toUpperCase().contains("WPA")) { // WPA Network
Toast.makeText(this,"WPA Network",Toast.LENGTH_SHORT).show();
wifiConfig.preSharedKey = String.format("\"%s\"",networkPass);
;
} else { // OPEN Network.
Toast.makeText(this,"OPEN Network",Toast.LENGTH_SHORT).show();
wifiConfig.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.NONE);
}
int netId = wifiManager.addNetwork(wifiConfig);//
wifiManager.disconnect();
wifiManager.enableNetwork(netId,true);
return wifiManager.reconnect();
}