问题
As title states I wanted to ask, how can I keep checking if the device has internet connection? I use the following class:
import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.util.Log;
public class checkConnection {
private static checkConnection instance = new checkConnection();
static Context context;
ConnectivityManager connectivityManager;
NetworkInfo wifiInfo, mobileInfo;
boolean connected = false;
public static checkConnection getInstance(Context ctx) {
context = ctx.getApplicationContext();
return instance;
}
public boolean isOnline() {
try {
connectivityManager = (ConnectivityManager) context
.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();
connected = networkInfo != null && networkInfo.isAvailable() &&
networkInfo.isConnected();
return connected;
} catch (Exception e) {
System.out.println("CheckConnectivity Exception: " + e.getMessage());
Log.v("connectivity", e.toString());
}
return connected;
}
}
But this only checks once the activity starts if the device has or not internet connection, if I wanted to keep checking how can I create a loop throughout the activity?
回答1:
public class NetworkChangeReceiver extends BroadcastReceiver {
@Override
public void onReceive(final Context context, final Intent intent) {
if(checkInternet(context))
{
Toast.makeText(context, "Network Available Do operations",Toast.LENGTH_LONG).show();
}
}
boolean checkInternet(Context context) {
ServiceManager serviceManager = new ServiceManager(context);
if (serviceManager.isNetworkAvailable()) {
return true;
} else {
return false;
}
}
}
ServiceManager.java
public class ServiceManager extends ContextWrapper {
public ServiceManager(Context base) {
super(base);
}
public boolean isNetworkAvailable() {
ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo networkInfo = cm.getActiveNetworkInfo();
if (networkInfo != null && networkInfo.isConnected()) {
return true;
}
return false;
}
}
permissions :
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.INTERNET" />
And don't forget to register the receiver like this in main activity -
registerReceiver(mConnReceiver,
new IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION));
}
}
ref. here
回答2:
You have to use Brodcast Receiver to register a listner whenever connectivity change and then check internet connection like this.
public class NetworkConnectivityListener {
private static final String TAG = "NetworkConnectivityListener";
private static final boolean DBG = true;
private Context mContext;
private State mState;
private boolean mListening;
private String mReason;
private boolean mIsFailover;
boolean isWifiConnected = false;
boolean isMobileConnected = false;
private static NetworkConnectivityListener Networkobject;
private MainThreadBus mThreadBus;
public static NetworkConnectivityListener newInstance() {
if (Networkobject == null) {
Networkobject = new NetworkConnectivityListener();
}
return Networkobject;
}
/** Network connectivity information */
private NetworkInfo mNetworkInfo;
/**
* In case of a Disconnect, the connectivity manager may have already
* established, or may be attempting to establish, connectivity with another
* network. If so, {@code mOtherNetworkInfo} will be non-null.
*/
private NetworkInfo mOtherNetworkInfo;
private ConnectivityBroadcastReceiver mReceiver;
private class ConnectivityBroadcastReceiver extends BroadcastReceiver {
@SuppressWarnings("deprecation")
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (!action.equals(ConnectivityManager.CONNECTIVITY_ACTION)
|| mListening == false) {
Log.d(TAG, "onReceived() called with " + mState.toString()
+ " and " + intent);
return;
}
ConnectivityManager connMgr = (ConnectivityManager) context
.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo networkInfo = connMgr
.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
if (networkInfo != null)
isWifiConnected = networkInfo.isConnected();
networkInfo = connMgr
.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);
if (networkInfo != null)
isMobileConnected = networkInfo.isConnected();
Log.d("network status", "wifi == " + isWifiConnected
+ " and mobile == " + isMobileConnected);
boolean noConnectivity = intent.getBooleanExtra(
ConnectivityManager.EXTRA_NO_CONNECTIVITY, false);
if (noConnectivity) {
mState = State.NOT_CONNECTED;
} else {
mState = State.CONNECTED;
}
mNetworkInfo = (NetworkInfo) intent
.getParcelableExtra(ConnectivityManager.EXTRA_NETWORK_INFO);
mOtherNetworkInfo = (NetworkInfo) intent
.getParcelableExtra(ConnectivityManager.EXTRA_OTHER_NETWORK_INFO);
mReason = intent.getStringExtra(ConnectivityManager.EXTRA_REASON);
mIsFailover = intent.getBooleanExtra(
ConnectivityManager.EXTRA_IS_FAILOVER, false);
System.out.println("Printing the MYTest" + mNetworkInfo);
if (DBG) {
Log.d(TAG,
"onReceive(): mNetworkInfo="
+ mNetworkInfo
+ " mOtherNetworkInfo = "
+ (mOtherNetworkInfo == null ? "[none]"
: mOtherNetworkInfo + " noConn="
+ noConnectivity) + " mState="
+ mState.toString());
}
mThreadBus.post(getState());
}
};
public enum State {
UNKNOWN,
/** This state is returned if there is connectivity to any network **/
CONNECTED,
/**
* This state is returned if there is no connectivity to any network.
* This is set to true under two circumstances:
* <ul>
* <li>When connectivity is lost to one network, and there is no other
* available network to attempt to switch to.</li>
* <li>When connectivity is lost to one network, and the attempt to
* switch to another network fails.</li>
*/
NOT_CONNECTED
}
/**
* Create a new NetworkConnectivityListener.
*/
public NetworkConnectivityListener() {
mState = State.UNKNOWN;
mReceiver = new ConnectivityBroadcastReceiver();
}
/**
* This method starts listening for network connectivity state changes.
*
* @param context
*/
public synchronized void startListening(Context context,Bus bus) {
if (!mListening) {
mContext = context;
mThreadBus=new MainThreadBus(bus);
IntentFilter filter = new IntentFilter();
filter.addAction(ConnectivityManager.CONNECTIVITY_ACTION);
context.registerReceiver(mReceiver, filter);
mListening = true;
}
}
/**
* This method stops this class from listening for network changes.
*/
public synchronized void stopListening() {
if (mListening) {
mContext.unregisterReceiver(mReceiver);
mContext = null;
mNetworkInfo = null;
mOtherNetworkInfo = null;
mIsFailover = false;
mReason = null;
mThreadBus=null;
mListening = false;
}
}
public State getState() {
return mState;
}
/**
* Return the NetworkInfo associated with the most recent connectivity
* event.
*
* @return {@code NetworkInfo} for the network that had the most recent
* connectivity event.
*/
public NetworkInfo getNetworkInfo() {
return mNetworkInfo;
}
/**
* If the most recent connectivity event was a DISCONNECT, return any
* information supplied in the broadcast about an alternate network that
* might be available. If this returns a non-null value, then another
* broadcast should follow shortly indicating whether connection to the
* other network succeeded.
*
* @return NetworkInfo
*/
public NetworkInfo getOtherNetworkInfo() {
return mOtherNetworkInfo;
}
/**
* Returns true if the most recent event was for an attempt to switch over
* to a new network following loss of connectivity on another network.
*
* @return {@code true} if this was a failover attempt, {@code false}
* otherwise.
*/
public boolean isFailover() {
return mIsFailover;
}
/**
* An optional reason for the connectivity state change may have been
* supplied. This returns it.
*
* @return the reason for the state change, if available, or {@code null}
* otherwise.
*/
public String getReason() {
return mReason;
}
public boolean iswifiConnected() {
return isWifiConnected;
}
public boolean ismobileConnected() {
return isMobileConnected;
}
public class MainThreadBus extends Bus {
private final Bus mBus;
private final Handler mHandler = new Handler(Looper.getMainLooper());
public MainThreadBus(final Bus bus) {
if (bus == null) {
throw new NullPointerException("bus must not be null");
}
mBus = bus;
}
@Override
public void post(final Object event) {
System.out.println("Printing the Value of Send" + event);
if (Looper.myLooper() == Looper.getMainLooper()) {
mBus.post(event);
} else {
mHandler.post(new Runnable() {
@Override
public void run() {
mBus.post(event);
}
});
}
}
}
}
来源：https://stackoverflow.com/questions/26730683/keep-checking-if-device-has-internet-connection