IOException无法解析主机,没有与主机名关联的地址 [英] IOException Unable to resolve host,No address associated with hostname
问题描述
我正在研究通过WiFi连接的Sony Remote相机.我需要使用相机单击图片,然后将其上传到另一个活动中的FTP服务器.因为我需要断开相机wifi并连接连接到另一个wifi网络或移动数据.当我连接到另一个wifi/移动数据并打算将图片上传到FTP服务器时,出现此错误.
I am working on Sony Remote camera which is connected using WiFi.I need to click a picture using a camera and then upload it to my FTP server which is in another activity.for than I need to disconnect my camera wifi and connect to the another wifi network or mobile data.when I connect to the another wifi/mobile data and going to upload the picture on FTP server I got this error.
IOException无法解析主机没有与主机名关联的地址
IOException Unable to resolve host No address associated with hostname
当关闭应用程序并重新启动时,然后直接上载图片而无需连接/断开相机,效果不佳. 有人,请告诉我我该怎么解决,因为我检查了堆栈溢出中的每个解决方案,而没有一个解决方案对我有用.
When a close application and start again, And then directly upload pictures without connecting/disconnection camera than it works fine. someone, please tell me how can I solve this, because I checked each and every solution on stack overflow and not one solution work for me.
我添加了以下权限
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.CHANGE_NETWORK_STATE"/>
<uses-permission android:name="android.permission.WRITE_SETTINGS"/>
推荐答案
与网络的连接不是中间的. 另外,如果所需的网络没有互联网连接,则在最新版本的Android中将无法连接(如果用户进行了连接,则弹出窗口将显示确认连接的提示).
Connection to a network is not inmediate. Also, if the desired network has no internet connection, in recent versions of Android it will not connect (if the connection is made by a user, a popup shows a confirmation to connnect).
我使用Android API(两个版本,一个用于API <21,另一个用于API> = 21)解决了这两个问题.
I solved both problems using Android APIs (2 versions, one for API<21 and the other for API>=21).
尝试以下代码(我使用AndroidAnnotations进行依赖项注入,但不是必需的):
Try this code (I'm using AndroidAnnotations for dependency injection, but is not required):
public class WifiHelper extends BroadcastReceiver {
@RootContext
Context context;
@SystemService
ConnectivityManager connectivityManager;
@SystemService
WifiManager wifiManager;
// For API>=21
private WifiHelperNetworkCallback wnc;
// For API<21
private boolean isBroadcastRegistered;
private String desiredSSID;
private Runnable callback;
public void enableNetwork(String ssid, int networkId, Runnable callback) {
desiredSSID = ssid;
wifiManager.enableNetwork(networkId, true);
configureNetworkRequest();
}
private void networkAvailable() {
// this method will be called when the network is available
callback.run();
}
private void configureNetworkRequest() {
if (android.os.Build.VERSION.SDK_INT >= 21) {
configureNetworkRequestAPI21();
} else {
configureNetworkRequestLegacy();
}
}
@TargetApi(21)
private void configureNetworkRequestAPI21() {
NetworkRequest request = new NetworkRequest.Builder()
.addTransportType(NetworkCapabilities.TRANSPORT_WIFI)
.build();
if (wnc == null) wnc = new WifiHelperNetworkCallback(this, connectivityManager);
connectivityManager.requestNetwork(request, wnc);
}
private void configureNetworkRequestLegacy() {
unregisterReceiver();
connectivityManager.startUsingNetworkFeature(ConnectivityManager.TYPE_WIFI, null);
IntentFilter intent = new IntentFilter();
intent.addAction(ConnectivityManager.CONNECTIVITY_ACTION);
intent.addAction(WifiManager.NETWORK_STATE_CHANGED_ACTION);
context.registerReceiver(this, intent);
isBroadcastRegistered = true;
}
@TargetApi(21)
private void disableNetworkRequest() {
if (android.os.Build.VERSION.SDK_INT >= 21) {
if (wnc != null) connectivityManager.unregisterNetworkCallback(wnc);
ConnectivityManager.setProcessDefaultNetwork(null);
} else {
unregisterReceiver();
}
}
private void unregisterReceiver() {
if (isBroadcastRegistered) {
context.unregisterReceiver(this);
isBroadcastRegistered = false;
}
}
// API<21
@Override
public void onReceive(Context context, Intent intent) {
if(intent.getAction().equals(WifiManager.NETWORK_STATE_CHANGED_ACTION)) {
NetworkInfo networkInfo =
intent.getParcelableExtra(WifiManager.EXTRA_NETWORK_INFO);
if(networkInfo.isConnected()) {
// Wifi is connected
if (desiredSSID.equals(getCurrentSSID())) {
// Callback and unregister
networkAvailable();
unregisterReceiver();
}
}
}
}
public String getCurrentSSID() {
WifiInfo wifiInfo = wifiManager.getConnectionInfo();
if (wifiInfo != null && wifiInfo.getSupplicantState()== SupplicantState.COMPLETED) {
return ssidWithoutQuotes(wifiInfo.getSSID());
}
else return null;
}
protected static String ssidWithoutQuotes(String ssid) {
if (ssid == null) return null;
else if (ssid.startsWith("\"") && ssid.endsWith("\"")) {
return ssid.substring(1, ssid.length() - 1);
} else {
return ssid;
}
}
protected String getDesiredSSID() {
return desiredSSID;
}
@TargetApi(21)
public static class WifiHelperNetworkCallback extends ConnectivityManager.NetworkCallback {
public final String LOG_TAG = WifiHelper.class.getSimpleName();
private ConnectivityManager connectivityManager;
private WifiHelper wifiHelper;
public WifiHelperNetworkCallback(WifiHelper wifiHelper, ConnectivityManager connectivityManager) {
this.wifiHelper = wifiHelper;
this.connectivityManager = connectivityManager;
}
public void onAvailable(Network network) {
// Do something once the network is available
NetworkInfo info = connectivityManager.getNetworkInfo(network);;
Log.i(LOG_TAG, "networkcallback!! " + info.getExtraInfo());
String desiredSSID = wifiHelper.getDesiredSSID();
if (desiredSSID != null && desiredSSID.equals(ssidWithoutQuotes(info.getExtraInfo()))) {
ConnectivityManager.setProcessDefaultNetwork(network);
wifiHelper.networkAvailable();
}
}
}
}
您将需要以下权限:
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.CHANGE_WIFI_MULTICAST_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.CHANGE_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.VIBRATE" android:maxSdkVersion="18"/>
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