禁用三星"自动网络交换机"进行WiFi连接

Question

在我们的应用程序中,我们处理启动到设备的WiFi连接,该设备广播其自己的无线接入点(没有互联网连接)以进行直接通信.

它在我们所有的测试设备上都能很好地工作; 然而,我们收到用户的报告,在某些三星设备(Galaxy S4,Galaxy Note 3)上,在Wi-Fi设置下有一个名为"自动网络交换机"的设置,三星已经添加了这个设置,寻找"不稳定"的网络,以及将自动断开连接并恢复为移动数据.不幸的是,由于我们的设备没有互联网连接,三星将其报告为不稳定的网络并立即断开连接.

我没有这些设备可用于测试,所以我很好奇是否有其他人知道这个问题或知道如何以编程方式禁用此设置或解决它？

我们用于连接的代码是:

/**
 * Attempt to connect to an open wifi network with the given SSID
 * @param ssid the SSID of the unsecured wireless network to connect to
 */
public static void connectToOpenNetwork (String ssid) {
    WifiManager mgr = getManager();
    WifiConfiguration configuration = getOpenWifiConfiguration(ssid);
    mgr.addNetwork(configuration);
    mgr.saveConfiguration();

    int res = findOpenNetworkId(ssid);
    if (res != INVALID_NETWORK_ID) {
        mgr.enableNetwork(res, true);
        mgr.reconnect();
    } else {
        Log.e(TAG, "Received request to connect to network " + ssid + " but the network was not found in the configurations.");
    }
}

/**
 * Get a WifiConfiguration object configured for an unsecured wireless network with the
 * given SSID.
 * @param ssid the SSID of the network to configure
 * @return a WifiConfiguration object that can be passed to
 * {@link WifiManager#addNetwork(android.net.wifi.WifiConfiguration)}
 */
private static WifiConfiguration getOpenWifiConfiguration (String ssid) {
    WifiConfiguration config = new WifiConfiguration();

    config.SSID = "\"" + ssid + "\"";
    config.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.NONE);

    return config;
}

Answer 1

编辑:所以,对那些感兴趣的人进一步研究,它似乎是基于4.3的三星Touchwiz版本中添加的功能.在内部,该设置名为"wifi_watchdog_connectivity_check".我仍然可以使用下面的代码,看看我能检查确保该设置是否已启用,但除此之外,我必须承担起它的上.

所以我发现,在您尝试建立连接并且操作系统切换远离网络后,Wi-Fi配置处于"禁用"状态.因此,在问题发生后,您可以通过检查配置的状态来检测它是否已经发生WifiManager.

WifiManager m = (WifiManger) getSystemService(Context.WIFI_SERVICE);
List<WifiConfiguration> networks = m.getConfiguredNetworks();
String mySsid = "My Network";
mySsid = "\"" + mySsid + "\"";

boolean isDisabled = false;
for (WifiConfiguration config : networks) {
    if (mySsid.equals(config.SSID)) {
        if (config.status = WifiConfiguration.Status.DISABLED) {
            isDisabled = true;
            break;
        }
    }
}

//If isDisabled is true, the network was disabled by the OS

然后,您可以尝试从系统设置应用程序中解析设置的名称:

/** Gets the resources of another installed application */
private static Resources getExternalResources(Context ctx, String namespace) {
    PackageManager pm = ctx.getPackageManager();
    try {
        return (pm == null) ? null : pm.getResourcesForApplication(namespace);
    } catch (PackageManager.NameNotFoundException ex) {
        return null;
    }
}

/** Gets a resource ID from another installed application */
private static int getExternalIdentifier(Context ctx, String namespace, 
        String key, String type) {
    Resources res = getExternalResources(ctx, namespace);
    return (res == null) ? 0 : res.getIdentifier(key, type, namespace);
}

/** Gets a String resource from another installed application */
public static String getExternalString(Context ctx, String namespace, 
        String key, String defVal) {
    int resId = getExternalIdentifier(ctx, namespace, key, "string");
    if (resId != 0) {
        Resources res = getExternalResources(ctx, namespace);
        return res.getString(resId);
    } else {
        return defVal;
    }
}

然后用它来获取字符串:

String autoNetworkSwitch = getExternalString(this, "com.android.settings",
        "wifi_watchdog_connectivity_check", "Unknown");

如果字符串存在,这将返回当前用户语言的本地化字符串.

对于任何对此结果感兴趣的人来说,事实证明这个选项实际上是一个Android设置,但它似乎在这些三星设备上更具侵略性.该设置是隐藏设置,可在android.provider.Settings.java以下位置找到:

/**
 * Setting to turn off poor network avoidance on Wi-Fi. Feature is enabled by default and
 * the setting needs to be set to 0 to disable it.
 * @hide
 */
public static final String WIFI_WATCHDOG_POOR_NETWORK_TEST_ENABLED =
       "wifi_watchdog_poor_network_test_enabled";

这是Settings$Secure为了什么API == 15 || API == 16,或Settings$Global为API >= 17.这不是第三方应用程序可以启用或禁用的设置; 但是,可以检测并警告它.我的解决方案是:

import static android.os.Build.VERSION.SDK_INT;
import static android.os.Build.VERSION_CODES.ICE_CREAM_SANDWICH_MR1;
import static android.os.Build.VERSION_CODES.JELLY_BEAN_MR1;

/**
 * Checks whether the "Avoid poor networks" setting (named "Auto network switch" on 
 * some Samsung devices) is enabled, which can in some instances interfere with Wi-Fi.
 *
 * @return true if the "Avoid poor networks" or "Auto network switch" setting is enabled
 */
public static boolean isPoorNetworkAvoidanceEnabled (Context ctx) {
    final int SETTING_UNKNOWN = -1;
    final int SETTING_ENABLED = 1;
    final String AVOID_POOR = "wifi_watchdog_poor_network_test_enabled";
    final String WATCHDOG_CLASS = "android.net.wifi.WifiWatchdogStateMachine";
    final String DEFAULT_ENABLED = "DEFAULT_POOR_NETWORK_AVOIDANCE_ENABLED";
    final ContentResolver cr = ctx.getContentResolver();

    int result;

    if (SDK_INT >= JELLY_BEAN_MR1) {
        //Setting was moved from Secure to Global as of JB MR1
        result = Settings.Global.getInt(cr, AVOID_POOR, SETTING_UNKNOWN);
    } else if (SDK_INT >= ICE_CREAM_SANDWICH_MR1) {
        result = Settings.Secure.getInt(cr, AVOID_POOR, SETTING_UNKNOWN);
    } else {
        //Poor network avoidance not introduced until ICS MR1
        //See android.provider.Settings.java
        return false;
    }

    //Exit here if the setting value is known
    if (result != SETTING_UNKNOWN) {
        return (result == SETTING_ENABLED);
    }

    //Setting does not exist in database, so it has never been changed.
    //It will be initialized to the default value.
    if (SDK_INT >= JELLY_BEAN_MR1) {
        //As of JB MR1, a constant was added to WifiWatchdogStateMachine to determine 
        //the default behavior of the Avoid Poor Networks setting.
        try {
            //In the case of any failures here, take the safe route and assume the 
            //setting is disabled to avoid disrupting the user with false information
            Class wifiWatchdog = Class.forName(WATCHDOG_CLASS);
            Field defValue = wifiWatchdog.getField(DEFAULT_ENABLED);
            if (!defValue.isAccessible()) defValue.setAccessible(true);
            return defValue.getBoolean(null);
        } catch (IllegalAccessException ex) {
            return false;
        } catch (NoSuchFieldException ex) {
            return false;
        } catch (ClassNotFoundException ex) {
            return false;
        } catch (IllegalArgumentException ex) {
            return false;
        }
    } else {
        //Prior to JB MR1, the default for the Avoid Poor Networks setting was
        //to enable it unless explicitly disabled
        return true;
    }
}

为了更好地衡量,您可以通过以下方式将用户定向到高级Wi-Fi设置Intent:

/**
 *  Ensure that an Activity is available to receive the given Intent
 */
public static boolean activityExists (Context ctx, Intent intent) {
    final PackageManager mgr = ctx.getPackageManager();
    final ResolveInfo info = mgr.resolveActivity(i, PackageManager.MATCH_DEFAULT_ONLY);
    return (info != null);
}

public static void showAdvancedWifiIfAvailable (Context ctx) {
    final Intent i = new Intent(Settings.ACTION_WIFI_IP_SETTINGS);
    if (activityExists(ctx, i)) {
        ctx.startActivity(i);
    }
}

有趣的琐事:这Intent与Activity进入设置> Wi-Fi>高级相同,但会显示不同的标题(IP设置,高级Wi-Fi).