在 android 4.0.2..4.4.4 上运行的代码存在一些问题，但在 Android 5 上并不真正运行，我不知道为什么。基本上，下面的代码允许设置新 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 fragment 和输出信息放在这里。

...
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;
}

因此 WifiConfigurator.setIpAssigment() 调用下一段代码:

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));
}

但是由于某些原因找不到字段“ipAssignment”:

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 ，该字段就在那里。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。

我是怎么做的:

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;
}

接下来我在错误日志中看到:

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。 对如何更新 DNS 有任何想法吗？

最佳答案

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 中看到的那样或在 Github mirror .

Enum 定义和字段现在都在内部对象中，类型为 IpConfiguration(也是新的)。这些是使用反射访问无证水域的危险......:)

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”(从某种意义上说它不会抛出异常)但我还没有进一步测试它。

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

关于java - 以编程方式更改 Android 5 (L) 上的 WiFi 配置，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/27216369/