以编程方式更改 Android 5 (L) 上的 WiFi 配置

Question

在 android 4.0.2..4.4.4 上运行的代码存在一些问题，但在 Android 5 上并没有真正运行，我不知道为什么。基本上，下面的代码允许设置新的 WiFi 的 IP 分配类型：STATIC 或 DHCP。我使用的代码完全包含在这个答案中：https://stackoverflow.com/a/10309323/876360

我将尝试将最重要的代码片段与输出信息一起放在这里。

...
WifiConfigurator.setIpAssignment("STATIC", wifiConf);
...

wifiConf 在哪里

public static WifiConfiguration getCurrentWiFiConfiguration(Context context) {
    WifiConfiguration wifiConf = null;
    ConnectivityManager connManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo networkInfo = connManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
    if (networkInfo.isConnected()) {
        final WifiManager wifiManager = (WifiManager) context.getSystemService(Context.WIFI_SERVICE);
        final WifiInfo connectionInfo = wifiManager.getConnectionInfo();
        if (connectionInfo != null && !TextUtils.isEmpty(connectionInfo.getSSID())) {
            List<WifiConfiguration> configuredNetworks = wifiManager.getConfiguredNetworks();
            if(configuredNetworks != null){
                for (WifiConfiguration conf : configuredNetworks) {
                    if (conf.networkId == connectionInfo.getNetworkId()) {
                        wifiConf = conf;
                        break;
                    }
                }
            }
        }
    }
    return wifiConf;
}

所以WifiConfigurator.setIpAssigment() 调用下一个代码：

public static void setIpAssignment(String assign, WifiConfiguration wifiConf)
        throws SecurityException, IllegalArgumentException, NoSuchFieldException, IllegalAccessException {

    setEnumField(wifiConf, assign, "ipAssignment");
}

public static void setEnumField(Object obj, String value, String name)
        throws SecurityException, NoSuchFieldException, IllegalArgumentException, IllegalAccessException {
    Log.d("myApp", obj.getClass().toString());
    Field f = obj.getClass().getField(name);
    f.set(obj, Enum.valueOf((Class<Enum>) f.getType(), value));
}

但由于某种原因找不到“ipAssignment”字段：

11-30 12:40:54.343    5941-5941/com.myApp D/myApp﹕ class android.net.wifi.WifiConfiguration
11-30 12:40:54.344    5941-5941/com.myApp D/myApp﹕ Can't update network configuration. java.lang.NoSuchFieldException: ipAssignment
            at java.lang.Class.getField(Class.java:1048)
            at com.myApp.WifiConfigurator.setEnumField(WifiConfigurator.java:141)
            at com.myApp.WifiConfigurator.setIpAssignment(WifiConfigurator.java:25)
            at com.myApp.WifiConfigurator.updateWifiNetwork(WifiConfigurator.java:220)
            at com.myApp.ui.MainScreen.onAsyncTaskCompleted(MainScreen.java:251)
            at com.myApp.myAPI$UpdateIPTask.onPostExecute(myAPI.java:257)
            at com.myApp.myAPI$UpdateIPTask.onPostExecute(myAPI.java:194)
            at android.os.AsyncTask.finish(AsyncTask.java:632)
            at android.os.AsyncTask.access$600(AsyncTask.java:177)
            at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:645)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5221)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)

起初，我以为谷歌更改了该字段的名称。然后我检查了Android L preview source code，该字段在那里。我很困惑为什么会这样。

更新

感谢 Matiash 的一些输入，我能够更新 ipAssignment 类型，但我无法更新 DNS。要更新 DNS，ipAssigment 应该是静态的。根据this Google 停止使用 LinkProperties 进行静态配置，他们现在使用 StaticIpConfiguration 类。

那么我该怎么做：

public static void setDNS(InetAddress dns1, InetAddress dns2, WifiConfiguration wifiConf)
        throws SecurityException, IllegalArgumentException, NoSuchMethodException, InvocationTargetException,
        NoSuchFieldException, IllegalAccessException {

    Object linkProperties = null;
    ArrayList<InetAddress> mDnses;

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
        staticIpConf = wifiConf.getClass().getMethod("getStaticIpConfiguration").invoke(wifiConf);
        mDnses = (ArrayList<InetAddress>) getDeclaredField(staticIpConf, "dnsServers");
    }
    else{
        linkProperties = getField(wifiConf, "linkProperties");
        mDnses = (ArrayList<InetAddress>) getDeclaredField(linkProperties, "mDnses");
    }

    mDnses.clear();
    mDnses.add(dns1);
    mDnses.add(dns2);
}
public static Object getDeclaredField(Object obj, String name)
        throws SecurityException, NoSuchFieldException,
        IllegalArgumentException, IllegalAccessException {

    Field f = obj.getClass().getDeclaredField(name);
    f.setAccessible(true);
    Object out = f.get(obj);
    return out;
}

我在错误日志中看到的下一个：

12-22 09:00:49.854  25815-25815/com.myapp D/myapp﹕ Can't update network configuration. java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String java.lang.Object.toString()' on a null object reference
            at com.myapp.WifiConfigurator.getDeclaredField(WifiConfigurator.java:245)
            at com.myapp.WifiConfigurator.setDNS(WifiConfigurator.java:78)
            at com.myapp.WifiConfigurator.updateWifiNetwork(WifiConfigurator.java:356)

我的猜测是 staticIpConfiguration 在我调用它时不存在。我必须以某种方式初始化它。 关于如何更新 DNS 的任何想法？

Answer 1

虽然ipAssignment 字段仍然存在于L 预览版中（至少是grepcode 中的版本），但它不在发布版本中，正如您在"master" branch of the source code 或Github mirror 中看到的那样。

枚举定义和字段现在都在一个内部对象中，类型为IpConfiguration（也是新的）。这些是使用反射进入无证水域的危险...... :)

但是，调整代码以通过反射访问它并将其设置在那里很简单：

public static void setIpAssignment(String assign, WifiConfiguration wifiConf)
        throws SecurityException, IllegalArgumentException, NoSuchFieldException, IllegalAccessException, InvocationTargetException, NoSuchMethodException {

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
        Object ipConfiguration = wifiConf.getClass().getMethod("getIpConfiguration").invoke(wifiConf);
        setEnumField(ipConfiguration, assign, "ipAssignment");
    } else {
        setEnumField(wifiConf, assign, "ipAssignment");
    }
}

这段代码“有效”（在某种意义上它不会引发异常），但我没有进一步测试它。

---

请参阅How to configure a static IP address, netmask, gateway, DNS programmatically on Android 5.x (Lollipop) for Wi-Fi connection 了解更详细的解决方案。