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();
}
}
if(isConnected()){
Toast.makeText(getApplication(),"Thank you",Toast.LENGTH_SHORT).show();
}
else{
AlertDialog.Builder builder =
new AlertDialog.Builder(this, R.style.AppCompatAlertDialogStyle);
builder.setTitle("Amar Bhat");
builder.setMessage("Oops...You are not connected to Internet!!!");
builder.setPositiveButton("OK", null);
builder.setNegativeButton("Cancel", null);
builder.show();
//Toast.makeText(getApplication(),"You are not connected",Toast.LENGTH_SHORT).show();
}
//And outside the class define isConnected()
public boolean isConnected(){
ConnectivityManager connMgr = (ConnectivityManager) getSystemService(Activity.CONNECTIVITY_SERVICE);
NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();
if (networkInfo != null && networkInfo.isConnected())
return true;
else
return false;
}
// In minifest add these permission
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
这是最简单和简单的方法来检查互联网连接的wifi和移动数据。
public static boolean isConnected(Activity _context) {
if (_context != null) {
ConnectivityManager connMgr = (ConnectivityManager) _context.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo activeInfo = connMgr.getActiveNetworkInfo();
if (activeInfo != null && activeInfo.isConnected()) {
boolean wifiConnected = activeInfo.getType() == ConnectivityManager.TYPE_WIFI;
boolean mobileConnected = activeInfo.getType() == ConnectivityManager.TYPE_MOBILE;
if (wifiConnected || mobileConnected) {
Log.d(TAG, "Wifi Connected ");
return true;
} else {
showAlert(_context,_context.getString(R.string.err_no_internet));
return false;
}
} else {
showAlert(_context,_context.getString(R.string.err_no_internet));
return false;
}
} else {
Log.e(TAG, "networkConnectivity: Context NULL");
}
return false;
}
我做了这个代码,它是最简单的,它只是一个布尔值。
通过询问if(isOnline()){
如果存在连接,并且可以连接到页面,则会得到状态代码200(稳定连接)。
确保添加正确的INTERNET和ACCESS_NETWORK_STATE权限。
public boolean isOnline() {
ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo netInfo = cm.getActiveNetworkInfo();
if (netInfo != null && netInfo.isConnected()) {
try {
URL url = new URL("http://www.google.com");
HttpURLConnection urlc = (HttpURLConnection) url.openConnection();
urlc.setConnectTimeout(3000);
urlc.connect();
if (urlc.getResponseCode() == 200) {
return new Boolean(true);
}
} catch (MalformedURLException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return false;
}
看一下ConnectivityManager类。您可以使用这个类来获取主机上活动连接的信息。http://developer.android.com/reference/android/net/ConnectivityManager.html
编辑:你可以使用
Context.getSystemService(Context.CONNECTIVITY_SERVICE)
.getNetworkInfo(ConnectivityManager.TYPE_MOBILE)
or
Context.getSystemService(Context.CONNECTIVITY_SERVICE)
.getNetworkInfo(ConnectivityManager.TYPE_WIFI)
并解析返回NetworkInfo对象的DetailedState枚举
EDIT EDIT:查看是否可以访问主机
Context.getSystemService(Context.CONNECTIVITY_SERVICE)
.requestRouteToHost(TYPE_WIFI, int hostAddress)
显然,我使用Context.getSystemService(Context.CONNECTIVITY_SERVICE)作为代理来表示
ConnectivityManager cm = Context.getSystemService(Context.CONNECTIVITY_SERVICE);
cm.yourMethodCallHere();