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();
}
}
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; }
}
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
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();
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" />
