Android - 通过 ping url 地址检查互联网连接
Android - Check internet connection by pinging url address
我需要一个持续 ping 的后台服务 google。但我不知道该怎么做。我刚来这地方。我的方法不行就不重复了。它只工作一次,而且总是 returns "false" .
isConnectedToServer 函数
public boolean isConnectedToServer(String url, int timeout) {
try{
URL myUrl = new URL(url);
URLConnection connection = myUrl.openConnection();
connection.setConnectTimeout(timeout);
connection.connect();
return true;
} catch (Exception e) {
// Handle your exceptions
return false;
}}
onCreate
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if(isConnectedToServer("http://www.google.com",3000)){
Toast.makeText(this, "Okay", Toast.LENGTH_SHORT).show();
}else{
Toast.makeText(this, "Not Okay", Toast.LENGTH_SHORT).show();
}}
清单
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
我在屏幕上看到一次 Not Okay。只有一次。即使我有互联网连接。我该怎么办?
尝试创建一个扩展 AsyncTask
的 class
public class CheckInternet extends AsyncTask<Void, Void, Boolean>{
private static final String TAG = "CheckInternet";
private Context context;
public CheckInternet(Context context) {
this.context = context;
}
@Override
protected Boolean doInBackground(Void... voids) {
Log.d(TAG, "doInBackground: ");
ConnectivityManager cm =
(ConnectivityManager)context.getSystemService(Context.CONNECTIVITY_SERVICE);
assert cm != null;
NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
boolean isConnected = activeNetwork != null &&
activeNetwork.isConnected();
if (isConnected) {
if ( executeCommand()) return true;
}
return false;
}
private boolean executeCommand(){
System.out.println("executeCommand");
Runtime runtime = Runtime.getRuntime();
try
{
Process mIpAddrProcess = runtime.exec("/system/bin/ping -c "+"www.google.com");
int mExitValue = mIpAddrProcess.waitFor();
System.out.println(" mExitValue "+mExitValue);
if(mExitValue==0){
return true;
}else{
return false;
}
}
catch (InterruptedException ignore)
{
ignore.printStackTrace();
System.out.println(" Exception:"+ignore);
}
catch (IOException e)
{
e.printStackTrace();
System.out.println(" Exception:"+e);
}
return false;
}
我需要一个持续 ping 的后台服务 google。但我不知道该怎么做。我刚来这地方。我的方法不行就不重复了。它只工作一次,而且总是 returns "false" .
isConnectedToServer 函数
public boolean isConnectedToServer(String url, int timeout) {
try{
URL myUrl = new URL(url);
URLConnection connection = myUrl.openConnection();
connection.setConnectTimeout(timeout);
connection.connect();
return true;
} catch (Exception e) {
// Handle your exceptions
return false;
}}
onCreate
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if(isConnectedToServer("http://www.google.com",3000)){
Toast.makeText(this, "Okay", Toast.LENGTH_SHORT).show();
}else{
Toast.makeText(this, "Not Okay", Toast.LENGTH_SHORT).show();
}}
清单
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
我在屏幕上看到一次 Not Okay。只有一次。即使我有互联网连接。我该怎么办?
尝试创建一个扩展 AsyncTask
的 classpublic class CheckInternet extends AsyncTask<Void, Void, Boolean>{
private static final String TAG = "CheckInternet";
private Context context;
public CheckInternet(Context context) {
this.context = context;
}
@Override
protected Boolean doInBackground(Void... voids) {
Log.d(TAG, "doInBackground: ");
ConnectivityManager cm =
(ConnectivityManager)context.getSystemService(Context.CONNECTIVITY_SERVICE);
assert cm != null;
NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
boolean isConnected = activeNetwork != null &&
activeNetwork.isConnected();
if (isConnected) {
if ( executeCommand()) return true;
}
return false;
}
private boolean executeCommand(){
System.out.println("executeCommand");
Runtime runtime = Runtime.getRuntime();
try
{
Process mIpAddrProcess = runtime.exec("/system/bin/ping -c "+"www.google.com");
int mExitValue = mIpAddrProcess.waitFor();
System.out.println(" mExitValue "+mExitValue);
if(mExitValue==0){
return true;
}else{
return false;
}
}
catch (InterruptedException ignore)
{
ignore.printStackTrace();
System.out.println(" Exception:"+ignore);
}
catch (IOException e)
{
e.printStackTrace();
System.out.println(" Exception:"+e);
}
return false;
}