我正在尝试在我的应用程序中编写一个部分，以区分Active Wifi连接和实际连接到Internet。使用连接管理器查明是否存在活动的Wifi连接非常简单但是每当我尝试测试是否可以在连接Wifi时连接到网站但没有互联网连接时我最终会进入无限循环。登记/> 我试图ping谷歌，但最终以同样的方式结束：
Process p1 = java.lang.Runtime.getRuntime().exec("ping -c 1 www.google.com");
int returnVal = 5;
try {
returnVal = p1.waitFor();
} catch (InterruptedException e) {
e.printStackTrace();
}
boolean reachable = (returnVal==0);
return reachable;
我也试过这段代码：
if (InetAddress.getByName("www.xy.com").isReachable(timeout))
{ }
else
{ }
但我无法使用isReachable工作。
答案 0 :(得分：24)
它对我有用：
验证网络可用性：
private Boolean isNetworkAvailable() {
ConnectivityManager connectivityManager
= (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
return activeNetworkInfo != null && activeNetworkInfo.isConnectedOrConnecting();
}
验证互联网访问权限：
public Boolean isOnline() {
try {
Process p1 = java.lang.Runtime.getRuntime().exec("ping -c 1 www.google.com");
int returnVal = p1.waitFor();
boolean reachable = (returnVal==0);
return reachable;
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return false;
}
答案 1 :(得分：10)
我用这个：
public static void isNetworkAvailable(Context context){
HttpGet httpGet = new HttpGet("http://www.google.com");
HttpParams httpParameters = new BasicHttpParams();
// Set the timeout in milliseconds until a connection is established.
// The default value is zero, that means the timeout is not used.
int timeoutConnection = 3000;
HttpConnectionParams.setConnectionTimeout(httpParameters, timeoutConnection);
// Set the default socket timeout (SO_TIMEOUT)
// in milliseconds which is the timeout for waiting for data.
int timeoutSocket = 5000;
HttpConnectionParams.setSoTimeout(httpParameters, timeoutSocket);
DefaultHttpClient httpClient = new DefaultHttpClient(httpParameters);
try{
Log.d(TAG, "Checking network connection...");
httpClient.execute(httpGet);
Log.d(TAG, "Connection OK");
return;
}
catch(ClientProtocolException e){
e.printStackTrace();
}
catch(IOException e){
e.printStackTrace();
}
Log.d(TAG, "Connection unavailable");
}
它来自另一个stackoverflow答案，但我找不到它。
编辑：
答案 2 :(得分：3)
要检查Android设备是否具有活动连接，我使用下面的hasActiveInternetConnection（）方法，（1）尝试检测网络是否可用，（2）然后连接到google.com以确定网络是否是活性
public static boolean hasActiveInternetConnection(Context context) {
if (isNetworkAvailable(context)) {
if (connectGoogle()) {
return true;
} else { //one more try
return connectGoogle();
}
} else {
log("No network available! (in hasActiveInternetConnection())");
return false;
}
}
public static boolean isNetworkAvailable(Context ct) {
ConnectivityManager connectivityManager = (ConnectivityManager) ct.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
return activeNetworkInfo != null;
}
public static boolean connectGoogle() {
try {
HttpURLConnection urlc = (HttpURLConnection)(new URL("http://www.google.com").openConnection());
urlc.setRequestProperty("User-Agent", "Test");
urlc.setRequestProperty("Connection", "close");
urlc.setConnectTimeout(10000);
urlc.connect();
return (urlc.getResponseCode() == 200);
} catch (IOException e) {
log("IOException in connectGoogle())");
return false;
}
}
答案 3 :(得分：3)
这是一些现代代码，使用AsynTask来解决当你尝试在主线程上连接并且为用户引入一个带有冲洗和重复选项的警报时android崩溃的问题。
class TestInternet extends AsyncTask<Void, Void, Boolean> {
@Override
protected Boolean doInBackground(Void... params) {
try {
URL url = new URL("http://www.google.com");
HttpURLConnection urlc = (HttpURLConnection) url.openConnection();
urlc.setConnectTimeout(3000);
urlc.connect();
if (urlc.getResponseCode() == 200) {
return true;
}
} catch (MalformedURLException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
return false;
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return false;
}
return false;
}
@Override
protected void onPostExecute(Boolean result) {
if (!result) { // code if not connected
AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
builder.setMessage("An internet connection is required.");
builder.setCancelable(false);
builder.setPositiveButton(
"TRY AGAIN",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
dialog.cancel();
new TestInternet().execute();
}
});
AlertDialog alert11 = builder.create();
alert11.show();
} else { // code if connected
doMyStuff();
}
}
}
...
new TestInternet().execute();
答案 4 :(得分：2)
查询这样的网站：
通过向您的班级添加以下方法，让您的班级实施AsyncTaskCompleteListenere<Boolean>：
@Override
public void onTaskComplete(Boolean result) {
Toast.makeText(getApplicationContext(), "URL Exist:" + result, Toast.LENGTH_LONG).show();
// continue your job
}
如果要检查连接，请在要调用的类中添加一个简单的testConnection方法：
public void testConnection() {
URLExistAsyncTask task = new URLExistAsyncTask(this);
String URL = "http://www.google.com";
task.execute(new String[]{URL});
}
最后将URLExistAsyncTask类作为异步（后台）任务执行连接测试，并在完成后回调您的onTaskComplete方法：
public class URLExistAsyncTask extends AsyncTask<String, Void, Boolean> {
AsyncTaskCompleteListenere<Boolean> callback;
public URLExistAsyncTask(AsyncTaskCompleteListenere<Boolean> callback) {
this.callback = callback;
}
protected Boolean doInBackground(String... params) {
int code = 0;
try {
URL u = new URL(params[0]);
HttpURLConnection huc = (HttpURLConnection) u.openConnection();
huc.setRequestMethod("GET");
huc.connect();
code = huc.getResponseCode();
} catch (IOException e) {
return false;
} catch (Exception e) {
return false;
}
return code == 200;
}
protected void onPostExecute(Boolean result){
callback.onTaskComplete(result);
}
}
答案 5 :(得分：0)
我确实使用过这种方法。它对我有用！对于想要获得真正互联网的人来说！
public boolean isOnline() {
try {
HttpURLConnection httpURLConnection = (HttpURLConnection)(new URL("http://www.google.com").openConnection());
httpURLConnection.setRequestProperty("User-Agent", "Test");
httpURLConnection.setRequestProperty("Connection", "close");
httpURLConnection.setConnectTimeout(10000);
httpURLConnection.connect();
return (httpURLConnection.getResponseCode() == 200);
} catch (IOException e) {
e.printStackTrace();
return false;
}
}
每次都要做这个方法！只需使用接收器
和=>
httpURLConnection.getResponseCode() == 200
这意味着互联网已连接！
答案 6 :(得分：0)
您可以通过创建new parallel thread来计数时间：
final class QueryClass {
private int responseCode = -1;
private String makeHttpRequest(URL url) throws IOException {
String jsonResponse = "";
if(url == null) {
return null;
}
HttpURLConnection urlConnection = null;
InputStream inputStream = null;
try {
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setRequestMethod("GET");
urlConnection.setReadTimeout(5000 );
urlConnection.setConnectTimeout(5000 );
Thread thread = new Thread() {
@Override
public void run() {
super.run();
try {
sleep(5000);
} catch (InterruptedException e) {
e.printStackTrace();
}
if(responseCode == -1) {
//Perform error message
Intent intent = new Intent(context,ErrorsActivity.class);
intent.putExtra("errorTextMessage",R.string.errorNoInternet);
intent.putExtra("errorImage",R.drawable.no_wifi);
context.startActivity(intent);
}
}
};
thread.start();
urlConnection.connect();
responseCode = urlConnection.getResponseCode();
if (responseCode == 200) {
inputStream = urlConnection.getInputStream();
jsonResponse = readFromStream(inputStream);
}