调用 WifiManager.enableNetwork() 时，我看到我的调用线程挂在本机代码中。到目前为止，我只能在运行 Android 3.2.1 的摩托罗拉 Xoom 平板电脑上重现此挂起。我已经在其他几部手机和平板电脑（都运行 Froyo 或 Gingerbread）上进行了测试，但没有发现问题。Xoom 是我必须测试的唯一双核设备（我已经在 2 个不同的 Xooms 上重现了这个问题），所以我觉得在与 WifiManager 交互时遇到了一些非常微妙的 Android 线程要求。我的调用线程挂起的堆栈跟踪是：
BinderProxy.transact(int, Parcel, Parcel, int) line: not available [native method]
IWifiManager$Stub$Proxy.enableNetwork(int, boolean) line: 513
WifiManager.enableNetwork(int, boolean) line: 587
我的应用程序正在尝试连接到已知的 wifi 接入点，执行一些测试，然后将设备重新连接到其原始接入点（如果之前已连接）。在建立连接之前，我们已经验证了 wifi 已启用，并且我们已执行扫描以验证是否找到了我们的接入点 SSID。用于建立连接的代码在 AsyncTask 中运行，如下所示：
...
private WifiManager mWifiManager;
private List<WifiConfiguration> mConfiguredNets = new ArrayList<WifiConfiguration>();
private Object mConnectMonitor = new Object();
private NetworkInfo.State mNetworkState = State.UNKNOWN;
private final BroadcastReceiver mConnectionStateReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context inContext, final Intent inIntent) {
final String action = inIntent.getAction();
if (WifiManager.NETWORK_STATE_CHANGED_ACTION.equals(action)) {
NetworkInfo ni =
(NetworkInfo)inIntent.getParcelableExtra(WifiManager.EXTRA_NETWORK_INFO);
State state = ni.getState();
if (state == State.CONNECTED) {
synchronized (mConnectMonitor) {
mNetworkState = state;
mConnectMonitor.notify();
}
}
}
}
};
public void runninInAsyncTask(Context activityContext, int networkID) {
mWifiManager = (WifiManager)activityContext.getSystemService(Context.WIFI_SERVICE);
// Register our broadcast receiver to get network state change events
IntentFilter ifilter = new IntentFilter();
ifilter.addAction(WifiManager.NETWORK_STATE_CHANGED_ACTION);
activityContext.registerReceiver(mConnectionStateReceiver, ifilter);
// Get a list of our currently configured networks so we can re-enable
// them after connecting to the desired network
mConfiguredNets = mWifiManager.getConfiguredNetworks();
// Enable our network and disable all others
mWifiManager.enableNetwork(networkId, true);
// Start the reconnection process to connect to our desired network
synchronized (mConnectMonitor) {
mWifiManager.reconnect();
mConnectMonitor.wait(60000);
if (mNetworkState != State.CONNECTED) {
Log.e(TAG, "Problems connecting to desired network!");
}
else {
Log.e(TAG, "Successfully connected to desired network!");
}
}
// Re-enable all of our previously configured networks
for (WifiConfiguration wifiConfig : mConfiguredNets)
{
if (wifiConfig.status != Status.ENABLED) {
mWifiManager.enableNetwork(wifiConfig.networkId, false);
}
}
}
...
此代码基于 Android Gingerbread 开源代码中的 Wifi 设置菜单代码。有什么关于调用我缺少的 WifiManager.enableNetwork() 的吗？它必须在特定线程上运行吗？我尝试确保在 UI 线程上调用 enableNetwork()（通过将逻辑移动到广播接收器）。这似乎有点帮助，但我仍然能够重现挂起。也许这是 Honeycomb 特有的东西？目前，这 2 个 Xoom 是我唯一可用于测试的 Honeycomb 设备，因此它们是我拥有的唯一数据点。
G