We Keep Coding

Unable to scan or discover BT and BLE devices in android

I am a complete novice in Java and Android. I am trying to create a test app to listen for BLE and BT devices nearby. I have another device where I wrote some logic to broadcast its BLE beacons. I verified it using a playstore app. Now I am trying to write my own app on Android.
I have been reading the Android developer pages for guidance. I have literally followed every step of the following pages
https://developer.android.com/guide/topics/connectivity/bluetooth/setup
https://developer.android.com/guide/topics/connectivity/bluetooth/permissions
https://developer.android.com/guide/topics/connectivity/bluetooth/find-bluetooth-devices
https://developer.android.com/guide/topics/connectivity/bluetooth/find-ble-devices
Also, Note that I have used BARE MINIMUM CODE from the Android Developers page So here is what I have done.
1. First off I have added my permissions under AndroidManifest
Note1 : I am deploying this app to My phone running Android 11
Note2 : All this code is written inside MainActivity. I have not created any other activity class
<uses-permission android:name="android.permission.BLUETOOTH" android:maxSdkVersion="30" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" android:maxSdkVersion="30" />
<uses-permission android:name="android.permission.BLUETOOTH_SCAN" />
<uses-permission android:name="android.permission.BLUETOOTH_ADVERTISE" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />
2. Next I check if my BT is enabled.
if (bluetoothAdapter == null) {
blefinder.append("\nDEVICE DOES NOT SUPPORT BLUETOOTH");
}
else {
blefinder.append("\nDEVICE SUPPORTS BLUETOOTH");
}
I get the success message that BT is of course enabled
3. Next I check if my device supports BLE
if (!getPackageManager().hasSystemFeature(PackageManager.FEATURE_BLUETOOTH_LE)) {
blefinder.append("\nBLE NOT SUPPORTED ON THIS DEVICE : ");
finish();
}
else{
blefinder.append("\nBLE IS SUPPORTED ON THIS DEVICE : ");
}
I get the message that BLE is supported
4. Next I list my already paired/bonded devices
For this I call ListPairedAndBondedDevices(); in onCreate() itself right after the above steps. Function Definition Below.
private void ListPairedAndBondedDevices(){
#SuppressLint("MissingPermission") Set<BluetoothDevice> pairedDevices = bluetoothAdapter.getBondedDevices();
if (pairedDevices.size() > 0) {
// There are paired devices. Get the name and address of each paired device.
blefinder.append("\nPAIRED/BONDED DEVICES");
for (BluetoothDevice device : pairedDevices) {
blefinder.append("\n" + device.getName() + " | " + device.getAddress());
}
}
}
This also works like a charm and prints out my paired devices. The next 2 parts is where I face the problem.
5. The Problem Step | Part 1:
Here I register a Broadcast receiver to discover all BT devices in the vicinity. I've unbonded my BT headphones and kept it in pairing mode to verify this.
ListPairedAndBondedDevices(); // From previous code snippet
IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND); // New code statement
registerReceiver(BTReceiver, filter);// New code statement
Broadcast Receiver implementation
private final BroadcastReceiver BTReceiver = new BroadcastReceiver() {
#SuppressLint("MissingPermission")
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (BluetoothDevice.ACTION_FOUND.equals(action)) {
// Discovery has found a device. Get the BluetoothDevice
// object and its info from the Intent.
BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
blefinder.append("\n" + device.getName() + " | " + device.getAddress());
}
}
};
So This part didn't Work :(
If you see above, I am registering the BTReceiver in onCreate right after listing the already paired devices (by calling ListPairedAndBondedDevices()).
When I ran the debugger, this broadcast receiver never gets called.
6. The Problem Step | Part 2:
Right after this I try to scan for BLE Devices as well by callin scanLeDevice()
ListPairedAndBondedDevices(); // From previous snippet
IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND); // From previous snippet
registerReceiver(BTReceiver, filter);// From previous snippet
scanLeDevice(); // ---------------->>> CALLING THIS FUNCTION TO SCAN FOR BLE DEVICES
Implementation of scanLeDevice()
private void scanLeDevice() {
if (!scanning) {
// Stops scanning after a predefined scan period.
handler.postDelayed(new Runnable() {
#Override
public void run() {
scanning = false;
bluetoothLeScanner.stopScan(leScanCallback);
blefinder.append("\nSTOPPING BLE SCAN... TIMEOUT REACHED");
}
}, SCAN_PERIOD);
scanning = true;
bluetoothLeScanner.startScan(leScanCallback);
} else {
scanning = false;
bluetoothLeScanner.stopScan(leScanCallback);
blefinder.append("\nSTOPPING BLE SCAN");
}
}
Unfortunately this also fails. The debugger tells me that this part of the code is getting called.
And after 30 seconds of SCAN_PERIOD (The TIMEOUT that I've set), I get the message that the scanning has stopped (STOPPING BLE SCAN)
Now I have implemented the leScanCallback as well (i.e the Device Scan Callback)
private ScanCallback leScanCallback =
new ScanCallback() {
#Override
public void onScanResult(int callbackType, ScanResult result) {
super.onScanResult(callbackType, result);
blefinder.append("SOMETHING GOT SCANNED?");
blefinder.append("\n"+result.getDevice().toString());
// leDeviceListAdapter.addDevice(result.getDevice());
// leDeviceListAdapter.notifyDataSetChanged();
}
};
Notice that I am not using a ListAdapter since I have no idea about that concept. Hence for starters I am just trying to dump the results in a TextView represented by blefinder . This blefinder prints all the other texts so there is nothing wrong with that TextView variable. When I ran using the, debugger, it is not entering into the leScanCallback piece of code definition at all, even after 30 seconds, after scanLeDevice() function is executed.
I am a little lost here. Is there something I may be missing or doing wrong. It is supposed to be a simple, list the ble/bt devices around my vicinity.
I am happy to share any further information if I have missed. Just let me know in the comments.

Assuming you've done with the permissions that I've mentioned in the comments, we can implement a clean bluetooth LE scanner object and then use it in the UI.
First we implement a result consumer interface in order to deliver the results to the consumers which call the BleScanner.scan() method.
public interface ScanResultConsumer {
public void onDeviceFound(BluetoothDevice device, byte[] scanRecord, int rssi);
public void onScanningStarted();
public void onScanningStopped();
}
Now we need to implement the scanner object that manages the scanning events:
public class BleScanner {
private static final String TAG = BleScanner.class.getSimpleName();
private BluetoothLeScanner leScanner = null;
private BluetoothAdapter bleAdapter = null;
private Handler uiHandler = new Handler(Looper.getMainLooper);
private ScanResultConsumer scanResultConsumer;
private boolean scanning = false;
private final ArrayList<BluetoothDevice> foundDeviceList = new ArrayList<>();
public BleScanner(Context context) {
final BluetoothManager bluetoothManager = (BluetoothManager)
context.getSystemService(Context.BLUETOOTH_SERVICE);
bleAdapter = bluetoothManager.getAdapter();
if(bleAdapter == null) {
Log.d(TAG, "No bluetooth hardware.");
}
else if(!bleAdapter.isEnabled()){
Log.d(TAG, "Blutooth is off.");
}
}
public void scan(ScanResultConsumer scanResultConsumer, long scanTime){
foundDeviceList.clear();
if (scanning){
Log.d(TAG, "Already scanning.");
return;
}
Log.d(TAG, "Scanning...");
if(leScanner == null){
leScanner = bleAdapter.getBluetoothLeScanner();
}
if(scanTimeMs > 0) {
uiHandler.postDelayed(()-> {
if (scanning) {
Log.d(TAG, "Scanning is stopping.");
if(leScanner != null)
leScanner.stopScan(scanCallBack);
else
Log.d(TAG,"Scanner null");
setScanning(false);
}
}, scanTimeMs);
}
this.scanResultConsumer = scanResultConsumer;
leScanner.startScan(scanCallBack);
setScanning(true);
}
private final ScanCallback scanCallBack = new ScanCallback() {
#Override
public void onScanResult(int callbackType, ScanResult result) {
super.onScanResult(callbackType, result);
if (!scanning){
return;
}
if(foundDeviceList.contains(result.getDevice())) {
// This device has already been found
return;
}
// New device found, add it to the list in order to prevent duplications
foundDeviceList.add(result.getDevice());
if(scanResultConsumer != null) {
uiHandler.post(() -> {
scanResultConsumer.onDeviceFound(result.getDevice(),
result.getScanRecord().getBytes(), result.getRssi());
});
}
}
};
public boolean isScanning(){
return scanning;
}
void setScanning(boolean scanning){
this.scanning = scanning;
uiHandler.post(() -> {
if(scanResultConsumer == null) return;
if(!scanning){
scanResultConsumer.onScanningStopped();
// Nullify the consumer in order to prevent UI crashes
scanResultConsumer = null;
} else{
scanResultConsumer.onScanningStarted();
}
});
}
}
Finally we can use this clean implementation in anywhere we need. But do note that a context must be provided in order to create a BleScanner object.
public class MainActivity extends AppCompatActivity {
private BleScanner bleScanner;
private Button buttonScan
// Other codes...
#Override
public void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Other codes...
bleScanner = new BleScanner(getApplicationContext());
// Other codes...
// For example if you want to start scanning on a button press
// Let's say you have a button called buttonScan and initiated it
buttonScan = findViewById(R.id.scan_button);
buttonScan.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
bleScanner.scan(new ScanResultConsumer {
#Override
public void onDeviceFound(BluetoothDevice device, byte[] scanRecord, int rssi) {
// TODO Here you have a newly found device, do something.
}
#Override
q public void onScanningStarted() {
// TODO Scanning has just started, you may want to make some UI changes.
}
#Override
public void onScanningStopped() {
// TODO Scanning has just stopped, you may want to make some UI changes.
}
});
}
});
}
}
Note: I written this code in a plain editor not in Android Studio. So there may be some errors, let me know if any.

First you should check if your app was granted the location permission(s) in the Settings app > Apps <your_app> > permissions. Some permissions (like ACCESS_*_LOCATION and BLUETOOTH_ADMIN) need to be requested at runtime and granted by the user through a popup. Normally you should get a SecurityException or a logcat warning when trying to execute code requiring permissions which your app doesn't have, but it's not uncommon for android to skip over error handling.
Consider using this method to start the scan in order check its result code for potential additional info about what is (not) going on.
You might also get some clues by logging all actions received in BTReceiver.onReceive(), not just action found.
Lastly check if the location settings on your device to ensure that bluetooth scanning is turned on (Settings app > location > wifi and bluetooth scanning )

Display an alert when Internet connection is off

I have connected my android phone with LAN connection. I would like to display a toast or an alert when I disable LAN connection. I am trying the following code but its of no use. What am I missing ?
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
isNetworkAvailable(MainActivity.this);
}
// to check connection state
public static boolean isNetworkAvailable(Context context){
ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
Network network = connectivityManager.getActiveNetwork();
NetworkCapabilities networkCapabilities = connectivityManager.getNetworkCapabilities(network);
if(networkCapabilities == null){
Toast.makeText(context, "No Internet connection!", Toast.LENGTH_LONG).show();
}
return true;
}
}
I couldn't Use NetworkInfo since its been deprecated. Thanks in advance
UPDATE:
I solved my problem using the example from the link below.
Very well explained. Have a look :)
Detect internet Connection

First of all the code you showed will be triggered only when activity is created and only once. What you need is Monitor for changes in connectivity
As mentioned:
Apps targeting Android 7.0 (API level 24) and higher do not receive CONNECTIVITY_ACTION broadcasts if they declare the broadcast receiver in their manifest
Meaning that you will have to create a custom broadcast receiver (I use kotlin for android development, you should be able to translate that to java):
class NetworkStatusReceiver : BroadcastReceiver() {
override fun onReceive(context: Context?, intent: Intent?) {
// check intent action for the connection status
}
}
To use the receiver, you need to register it in your activity (a better choice would be to use a service if you need it across multiple activities):
val filter = IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION)
filter.addAction("mypackage.CONNECTIVITY_CHANGE")
val permissionReceiver = NetworkStatusReceiver()
registerReceiver(permissionReceiver, filter)
To avoid memory leaks or multiple bindings it is recommended to unbind the receiver once the lifecycle of you component ends, you can do that by:
unregisterReceiver(permissionReceiver)
Also don't forget to add to your manifest:
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

Try this
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if(isNetworkConnected){
}else{
Toast.makeText(context, "No Internet
connection!",Toast.LENGTH_LONG).show();
}
}
public boolean isNetworkConnected(Context context) {
ConnectivityManager cm = (ConnectivityManager)
context.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo netInfo = cm.getActiveNetworkInfo();
return netInfo != null && netInfo.isConnected();
}
}

First added network permissions in you manifest.xml file:
ex:
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
Then create and register a broadcast receiver class which will be notified whenever there is a change in network/internet connection.
Here is a good example
link: https://www.androidhive.info/2012/07/android-detect-internet-connection-status/

IOException Unable to resolve host,No address associated with hostname

I am working on Sony Remote camera which is connected using WiFi.I need to click a picture using a camera and then upload it to my FTP server which is in another activity.for than I need to disconnect my camera wifi and connect to the another wifi network or mobile data.when I connect to the another wifi/mobile data and going to upload the picture on FTP server I got this error.
IOException Unable to resolve host No address associated with hostname
When a close application and start again, And then directly upload pictures without connecting/disconnection camera than it works fine.
someone, please tell me how can I solve this, because I checked each and every solution on stack overflow and not one solution work for me.
I added bellow permissions
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.CHANGE_NETWORK_STATE"/>
<uses-permission android:name="android.permission.WRITE_SETTINGS"/>

Connection to a network is not inmediate.
Also, if the desired network has no internet connection, in recent versions of Android it will not connect (if the connection is made by a user, a popup shows a confirmation to connnect).
I solved both problems using Android APIs (2 versions, one for API<21 and the other for API>=21).
Try this code (I'm using AndroidAnnotations for dependency injection, but is not required):
public class WifiHelper extends BroadcastReceiver {
#RootContext
Context context;
#SystemService
ConnectivityManager connectivityManager;
#SystemService
WifiManager wifiManager;
// For API>=21
private WifiHelperNetworkCallback wnc;
// For API<21
private boolean isBroadcastRegistered;
private String desiredSSID;
private Runnable callback;
public void enableNetwork(String ssid, int networkId, Runnable callback) {
desiredSSID = ssid;
wifiManager.enableNetwork(networkId, true);
configureNetworkRequest();
}
private void networkAvailable() {
// this method will be called when the network is available
callback.run();
}
private void configureNetworkRequest() {
if (android.os.Build.VERSION.SDK_INT >= 21) {
configureNetworkRequestAPI21();
} else {
configureNetworkRequestLegacy();
}
}
#TargetApi(21)
private void configureNetworkRequestAPI21() {
NetworkRequest request = new NetworkRequest.Builder()
.addTransportType(NetworkCapabilities.TRANSPORT_WIFI)
.build();
if (wnc == null) wnc = new WifiHelperNetworkCallback(this, connectivityManager);
connectivityManager.requestNetwork(request, wnc);
}
private void configureNetworkRequestLegacy() {
unregisterReceiver();
connectivityManager.startUsingNetworkFeature(ConnectivityManager.TYPE_WIFI, null);
IntentFilter intent = new IntentFilter();
intent.addAction(ConnectivityManager.CONNECTIVITY_ACTION);
intent.addAction(WifiManager.NETWORK_STATE_CHANGED_ACTION);
context.registerReceiver(this, intent);
isBroadcastRegistered = true;
}
#TargetApi(21)
private void disableNetworkRequest() {
if (android.os.Build.VERSION.SDK_INT >= 21) {
if (wnc != null) connectivityManager.unregisterNetworkCallback(wnc);
ConnectivityManager.setProcessDefaultNetwork(null);
} else {
unregisterReceiver();
}
}
private void unregisterReceiver() {
if (isBroadcastRegistered) {
context.unregisterReceiver(this);
isBroadcastRegistered = false;
}
}
// API<21
#Override
public void onReceive(Context context, Intent intent) {
if(intent.getAction().equals(WifiManager.NETWORK_STATE_CHANGED_ACTION)) {
NetworkInfo networkInfo =
intent.getParcelableExtra(WifiManager.EXTRA_NETWORK_INFO);
if(networkInfo.isConnected()) {
// Wifi is connected
if (desiredSSID.equals(getCurrentSSID())) {
// Callback and unregister
networkAvailable();
unregisterReceiver();
}
}
}
}
public String getCurrentSSID() {
WifiInfo wifiInfo = wifiManager.getConnectionInfo();
if (wifiInfo != null && wifiInfo.getSupplicantState()== SupplicantState.COMPLETED) {
return ssidWithoutQuotes(wifiInfo.getSSID());
}
else return null;
}
protected static String ssidWithoutQuotes(String ssid) {
if (ssid == null) return null;
else if (ssid.startsWith("\"") && ssid.endsWith("\"")) {
return ssid.substring(1, ssid.length() - 1);
} else {
return ssid;
}
}
protected String getDesiredSSID() {
return desiredSSID;
}
#TargetApi(21)
public static class WifiHelperNetworkCallback extends ConnectivityManager.NetworkCallback {
public final String LOG_TAG = WifiHelper.class.getSimpleName();
private ConnectivityManager connectivityManager;
private WifiHelper wifiHelper;
public WifiHelperNetworkCallback(WifiHelper wifiHelper, ConnectivityManager connectivityManager) {
this.wifiHelper = wifiHelper;
this.connectivityManager = connectivityManager;
}
public void onAvailable(Network network) {
// Do something once the network is available
NetworkInfo info = connectivityManager.getNetworkInfo(network);;
Log.i(LOG_TAG, "networkcallback!! " + info.getExtraInfo());
String desiredSSID = wifiHelper.getDesiredSSID();
if (desiredSSID != null && desiredSSID.equals(ssidWithoutQuotes(info.getExtraInfo()))) {
ConnectivityManager.setProcessDefaultNetwork(network);
wifiHelper.networkAvailable();
}
}
}
}
You will need this permissions:
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.CHANGE_WIFI_MULTICAST_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.CHANGE_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.VIBRATE" android:maxSdkVersion="18"/>

Efficient approach to continuously check whether internet connection is available in Android [duplicate]

This question already has an answer here:
Closed 10 years ago.
Possible Duplicate:
How can I monitor the network connection status in Android?
I need to continuously check whether the internet is connected or not and update the text area accordingly with appropriate message . Now if i create an asynctask it will execute once and stop which is not what I want . I want to check at every moment continuously and obviously this should not be on the main thread .So Service wont be a good choice either . Can anyone help me What is the best and efficient approach to handle this . Thanks

do it with a receiver. you can be notified about network state change. for example,
private BroadcastReceiver networkReceiver = new BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
super.onReceive(context, intent);
if(intent.getExtras()!=null) {
NetworkInfo ni=(NetworkInfo) intent.getExtras().get(ConnectivityManager.EXTRA_NETWORK_INFO);
if(ni!=null && ni.getState()==NetworkInfo.State.CONNECTED) {
// we're connected
}
}
// we're not connected
}
}
register this in your onResume(), and unregister on onPause().
#Override
protected void onPause() {
super.onPause();
unregisterReceiver(networkReceiver);
}
#Override
protected void onResume() {
super.onResume();
IntentFilter filter = new IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION);
registerReceiver(networkReceiver, filter);
}
additionally, to obtain the initial state before your receiver has been registered, call this in your onResume() method,
public boolean isNetworkConnected() {
ConnectivityManager cm =
(ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo netInfo = cm.getActiveNetworkInfo();
if (netInfo != null && netInfo.isConnectedOrConnecting()) {
return true;
}
return false;
}
make sure your app requests this permission,
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

You don't need to constantly ask the OS if there is a network connection. Simply check whether a connection exists in onResume() and then use a BroadcastReceiver to listen for the CONNECTIVITY_ACTION Intent from the ConnectivityManager when the connection is changed and check EXTRA_NO_CONNECTIVITY.

Network listener Android

I want to check when the network of phone in Android goes off. Can I capture that event?
I am not getting the proper API or any example which would explain the same. If anyone had done or any example links would be really helpful.

New java class:
public class ConnectionChangeReceiver extends BroadcastReceiver
{
#Override
public void onReceive( Context context, Intent intent )
{
ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService( Context.CONNECTIVITY_SERVICE );
NetworkInfo activeNetInfo = connectivityManager.getActiveNetworkInfo();
NetworkInfo mobNetInfo = connectivityManager.getNetworkInfo( ConnectivityManager.TYPE_MOBILE );
if ( activeNetInfo != null )
{
Toast.makeText( context, "Active Network Type : " + activeNetInfo.getTypeName(), Toast.LENGTH_SHORT ).show();
}
if( mobNetInfo != null )
{
Toast.makeText( context, "Mobile Network Type : " + mobNetInfo.getTypeName(), Toast.LENGTH_SHORT ).show();
}
}
}
New xml in your AndroidManifest.xml under the "manifest" element:
<!-- Needed to check when the network connection changes -->
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
New xml in your AndroidManifest.xml under the "application" element:
<receiver android:name="com.blackboard.androidtest.receiver.ConnectionChangeReceiver"
android:label="NetworkConnection">
<intent-filter>
<action android:name="android.net.conn.CONNECTIVITY_CHANGE"/>
</intent-filter>
</receiver>

I have been using a small setup to check the bandwidth for determining how to scale things, such as images.
Under the activity, in AndroidManifest:
<intent-filter>
...
<action android:name="android.net.conn.CONNECTIVITY_CHANGE"/>
</intent-filter>
In the activity where the checks are being performed:
boolean network;
int bandwidth;
#Override
public void onCreate(Bundle savedInstanceState) {
...
network = isDataConnected();
bandwidth = isHighBandwidth();
registerReceiver(new BroadcastReceiver() {
public void onReceive(Context context, Intent intent) {
network = isDataConnected();
bandwidth = isHighBandwidth();
}
}, new IntentFilter("android.net.conn.CONNECTIVITY_CHANGE"));
...
}
...
private boolean isDataConnected() {
try {
ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
return cm.getActiveNetworkInfo().isConnectedOrConnecting();
} catch (Exception e) {
return false;
}
}
private int isHighBandwidth() {
ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo info = cm.getActiveNetworkInfo();
if (info.getType() == ConnectivityManager.TYPE_WIFI) {
WifiManager wm = (WifiManager) getSystemService(Context.WIFI_SERVICE);
return wm.getConnectionInfo().getLinkSpeed();
} else if (info.getType() == ConnectivityManager.TYPE_MOBILE) {
TelephonyManager tm = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);
return tm.getNetworkType();
}
return 0;
}
An example usage would then be:
if (network) {
if (bandwidth > 16) {
// Code for large items
} else if (bandwidth <= 16 && bandwidth > 8) {
// Code for medium items
} else {
//Code for small items
}
} else {
//Code for disconnected
}
It's not the prettiest, but it allows enough flexibility that I can change the bandwidth cutoff for items depending on what they are and my requirements for them.

If using Android Annotations is an option for you try this in your activities - that's all, the rest is generated:
#Receiver(actions = ConnectivityManager.CONNECTIVITY_ACTION,
registerAt = Receiver.RegisterAt.OnResumeOnPause)
void onConnectivityChange() {
//react
}
Use this only if you already use AndroidAnnotations - putting this dependency inside your project only for this piece of code would be overkill.

The above answer only works if mobile packet data is enabled. Otherwise, ConnectivityManager would be null and you can no longer retrieve NetworkInfo. The way around it is to use a PhoneStateListener or TelephonyManager instead.