我得到了一个AsyncTask，应该检查对主机名的网络访问。但是doInBackground()永远不会超时。有人知道吗?
public class HostAvailabilityTask extends AsyncTask<String, Void, Boolean> {
private Main main;
public HostAvailabilityTask(Main main) {
this.main = main;
}
protected Boolean doInBackground(String... params) {
Main.Log("doInBackground() isHostAvailable():"+params[0]);
try {
return InetAddress.getByName(params[0]).isReachable(30);
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return false;
}
protected void onPostExecute(Boolean... result) {
Main.Log("onPostExecute()");
if(result[0] == false) {
main.setContentView(R.layout.splash);
return;
}
main.continueAfterHostCheck();
}
}
使用以下方法检查互联网连接，同时ConnectivityManager.getActiveNetworkInfo()在API 28中已弃用
@Suppress("DEPRECATION")
fun isNetworkConnected(context: Context): Boolean {
val cm = context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager?
return cm?.run {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
cm.getNetworkCapabilities(cm.activeNetwork)?.run {
when {
hasTransport(NetworkCapabilities.TRANSPORT_WIFI) -> true
hasTransport(NetworkCapabilities.TRANSPORT_CELLULAR) -> true
hasTransport(NetworkCapabilities.TRANSPORT_ETHERNET) -> true
else -> false
}
}
} else {
cm.activeNetworkInfo?.run {
when (type) {
ConnectivityManager.TYPE_WIFI -> true
ConnectivityManager.TYPE_MOBILE -> true
else -> false
}
}
}
} ?: false
}
还要向清单添加以下权限
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
hatransport_ethernet (NetworkCapabilities.TRANSPORT_ETHERNET)用于为Android TV开发的应用程序，其中TV可以直接连接到以太网
使用以下方法检查互联网连接，同时ConnectivityManager.getActiveNetworkInfo()在API 28中已弃用
@Suppress("DEPRECATION")
fun isNetworkConnected(context: Context): Boolean {
val cm = context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager?
return cm?.run {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
cm.getNetworkCapabilities(cm.activeNetwork)?.run {
when {
hasTransport(NetworkCapabilities.TRANSPORT_WIFI) -> true
hasTransport(NetworkCapabilities.TRANSPORT_CELLULAR) -> true
hasTransport(NetworkCapabilities.TRANSPORT_ETHERNET) -> true
else -> false
}
}
} else {
cm.activeNetworkInfo?.run {
when (type) {
ConnectivityManager.TYPE_WIFI -> true
ConnectivityManager.TYPE_MOBILE -> true
else -> false
}
}
}
} ?: false
}
还要向清单添加以下权限
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
hatransport_ethernet (NetworkCapabilities.TRANSPORT_ETHERNET)用于为Android TV开发的应用程序，其中TV可以直接连接到以太网
不要检查WIFI连接或移动数据连接，试着点击任何托管域。以便您可以检查WIFI/Mobile连接是否具有连接公共互联网的能力。
如果您的移动设备能够连接到所提供的公共域，则将返回以下内容。
boolean isReachable()
{
boolean connected = false;
String instanceURL = "Your trusted domain name";
Socket socket;
try {
socket = new Socket();
SocketAddress socketAddress = new InetSocketAddress(instanceURL, 80);
socket.connect(socketAddress, 5000);
if (socket.isConnected()) {
connected = true;
socket.close();
}
} catch (IOException e) {
e.printStackTrace();
} finally {
socket = null;
}
return connected;
}
希望对大家有所帮助。
下面是我使用的方法:
public boolean isNetworkAvailable(final Context context) {
return ((ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE)).getActiveNetworkInfo() != null;
}
更好的是，检查确保它是“连接”的:
public boolean isNetworkAvailable(final Context context) {
final ConnectivityManager connectivityManager = ((ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE));
return connectivityManager.getActiveNetworkInfo() != null && connectivityManager.getActiveNetworkInfo().isConnected();
}
下面是如何使用该方法:
if (isNetworkAvailable(context)) {
// code here
} else {
// code
}
需要许可:
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
https://stackoverflow.com/a/16124915/950427
只需创建下面的类来检查internet连接:
public class ConnectionStatus {
private Context _context;
public ConnectionStatus(Context context) {
this._context = context;
}
public boolean isConnectionAvailable() {
ConnectivityManager connectivity = (ConnectivityManager) _context
.getSystemService(Context.CONNECTIVITY_SERVICE);
if (connectivity != null) {
NetworkInfo[] info = connectivity.getAllNetworkInfo();
if (info != null)
for (int i = 0; i < info.length; i++)
if (info[i].getState() == NetworkInfo.State.CONNECTED) {
return true;
}
}
return false;
}
}
该类仅包含一个返回连接状态布尔值的方法。因此，简单来说，如果该方法找到一个到Internet的有效连接，则返回值为true，否则为false，如果没有找到有效连接。
MainActivity中的下面的方法调用前面描述的方法的结果，并提示用户进行相应的操作:
public void addListenerOnWifiButton() {
Button btnWifi = (Button)findViewById(R.id.btnWifi);
iia = new ConnectionStatus(getApplicationContext());
isConnected = iia.isConnectionAvailable();
if (!isConnected) {
btnWifi.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
startActivity(new Intent(Settings.ACTION_WIFI_SETTINGS));
Toast.makeText(getBaseContext(), "Please connect to a hotspot",
Toast.LENGTH_SHORT).show();
}
});
}
else {
btnWifi.setVisibility(4);
warning.setText("This app may use your mobile data to update events and get their details.");
}
}
在上面的代码中，如果结果为假，(因此没有互联网连接，用户将被带到Android wi-fi面板，在那里他将被提示连接到wi-fi热点。
