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();
}
}
非常重要的是检查我们是否与isAvailable()有连接，以及是否可能与isConnected()建立连接
private static ConnectivityManager manager;
public static boolean isOnline(Context context) {
ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();
return networkInfo != null && networkInfo.isAvailable() && networkInfo.isConnected();
}
你可以取消网络活动WiFi的类型:
public static boolean isConnectedWifi(Context context) {
ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();
return networkInfo != null && networkInfo.getType() == ConnectivityManager.TYPE_WIFI;
}
或手机Móvil:
public static boolean isConnectedMobile(Context context) {
ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();
return networkInfo != null && networkInfo.getType() == ConnectivityManager.TYPE_MOBILE;
}
不要忘记权限:
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.INTERNET" />
如果你需要检查网络连接，使用ping到服务器的方法:
public boolean checkIntCON() {
try {
Process ipProcess = Runtime.getRuntime().exec("/system/bin/ping -c 1 8.8.8.8");
return (ipProcess.waitFor() == 0);
}
catch (IOException e) { e.printStackTrace(); }
catch (InterruptedException e) { e.printStackTrace(); }
return false;
}
您可以使用端口进行检查
public boolean checkIntCON() {
try {
Socket sock = new Socket();
SocketAddress sockaddr = new InetSocketAddress("8.8.8.8", 80);
// port will change according to protocols
sock.connect(sockaddr, 1250);
sock.close();
return true;
} catch (IOException e) { return false; }
}
Android提供了ConnectivityManager类来了解互联网连接状态。下面的方法将是非常有用的，以了解互联网连接状态。
首先在AndroidManifest.xml中添加INTERNET和ACCESS_NETWORK_STATE权限
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
然后使用下面的方法检查设备是否连接到互联网。如果设备已连接到互联网，此方法将返回true。
public boolean isInternetAvailable(Context context) {
ConnectivityManager connectivityManager = (ConnectivityManager)
context.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo activeNetwork = connectivityManager.getActiveNetworkInfo();
return activeNetwork != null
&& activeNetwork.isConnectedOrConnecting();
}
参考链接:—http://www.androidtutorialshub.com/android-check-internet-connection-status/
检查这段代码…这对我很有用:)
public static void isNetworkAvailable(final Handler handler, final int timeout) {
// ask fo message '0' (not connected) or '1' (connected) on 'handler'
// the answer must be send before before within the 'timeout' (in milliseconds)
new Thread() {
private boolean responded = false;
@Override
public void run() {
// set 'responded' to TRUE if is able to connect with google mobile (responds fast)
new Thread() {
@Override
public void run() {
HttpGet requestForTest = new HttpGet("http://m.google.com");
try {
new DefaultHttpClient().execute(requestForTest); // can last...
responded = true;
}
catch (Exception e) {
}
}
}.start();
try {
int waited = 0;
while(!responded && (waited < timeout)) {
sleep(100);
if(!responded ) {
waited += 100;
}
}
}
catch(InterruptedException e) {} // do nothing
finally {
if (!responded) { handler.sendEmptyMessage(0); }
else { handler.sendEmptyMessage(1); }
}
}
}.start();
}
然后，我定义处理程序:
Handler h = new Handler() {
@Override
public void handleMessage(Message msg) {
if (msg.what != 1) { // code if not connected
} else { // code if connected
}
}
};
.．.并启动测试:
isNetworkAvailable(h,2000); // get the answser within 2000 ms
