Develop Reference

How to get an event for wifi getting enabled or disabled

What is a way to listen and receive an event when Wifi is enabled or disabled on Android?
Note that I am not looking for connectivity to the internet. I am just looking for an event which says wifi in the wifi settings was enabled.

Use WIFI_STATE_CHANGED_ACTION broadcast intent action to check Wi-Fi state.
Add this to your manifest file:
<receiver
android:name=".WifiReceiver" >
<intent-filter>
<action android:name="android.net.wifi.STATE_CHANGE" />
</intent-filter>
</receiver>
And use this class for receiving broadcast:
public class WifiReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
// Check the state here
int state = intent.getIntExtra(WifiManager.EXTRA_WIFI_STATE, -1);
}
}

how to use broadcast receiver on receive

i have a project and when i run the application,one service should be active and when the device is turned on,my android service should be active.
The project runs in emulator successfully but in my phone when i turn on the device it doesn't works!
my broadcast receiver :
public class BroadcastReceiverOnTurnedOn extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
Intent startServiceIntent = new Intent(context, MyService.class);
context.startService(startServiceIntent);
}
}
i added :
<receiver android:name="com.dariran.BroadcastReceiverOnTurnedOn">
<intent-filter>
<action android:name="android.intent.action.BOOT_COMPLETED" />
</intent-filter>
</receiver>
to appliation tag on Manifest.xml and
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />

You are registering a BroadcastReceiver not a Service. Services will generally run in the background all of the time (if memory and resources permit).
Your broadcast receiver activates only when the device is rebooted - and your emulator "boots" every time you start it up. Your phone does not "boot" when the app is installed.
You should either register for events like "app installed" or else actually implement a service, like here:
http://www.vogella.com/tutorials/AndroidServices/article.html

You need to make sure that once you install the app on device it should be started once by clicking app icon then only boot receiver will receive boot event on subsequent reboots calls.

i undrestand that if i install app in internal storage in works successfully even device rebooted but when i install the app on external storage and then reboot device it not work
i have a project that when run application one service be active and when device be turn on my android service be active. the project run in device's internal memory successfully but when i install it on external memory and reboot my device again don't work!
for first i call my service in first acitivity and it works, but when i reboot my device it doesn't work !
my activity :
public class FirstClass extends Activity
{
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.first);
final Handler handler = new Handler();
handler.postDelayed(new Runnable()
{
public void run()
{
startService(new Intent(getApplicationContext(), MyService.class));
startActivity(new Intent(FirstClass.this, MainActivity.class));
finish();
}
},5000);
}
/////////////////////////////////////////////////
}
my broadcast receiver :
public class BroadcastReceiverOnTurnedOn extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
Intent startServiceIntent = new Intent(context, MyService.class);
context.startService(startServiceIntent);
}
}
i added :
<service
android:name="com.dariran.MyService"
android:enabled="true"
android:exported="true" >
</service>
<receiver android:name="com.dariran.BroadcastReceiverOnTurnedOn"
android:enabled="true">
<intent-filter android:priority="1">
<action android:name="android.intent.action.BOOT_COMPLETED" />
</intent-filter>
<intent-filter>
<action android:name="android.intent.action.ACTION_EXTERNAL_APPLICATIONS_AVAILABLE" />
</intent-filter>
</receiver>to appliation tag on Manifest.xml and
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
i added this code to my service class to put a filter to recognize the external storage but don't work again :(
#Override
public void onStart(Intent intent, int startId) {
try {
IntentFilter filter = new IntentFilter(Intent.ACTION_EXTERNAL_APPLICATIONS_AVAILABLE);
filter.addAction(Intent.ACTION_EXTERNAL_APPLICATIONS_AVAILABLE);
BroadcastReceiver mReceiver = new BroadcastReceiverOnTurnedOn();
registerReceiver(mReceiver, filter);
} catch (Exception e) {
}
}

How to receive intents for Bluetooth devices working?

I'm trying to have my app's service listen for Bluetooth connection and disconnection attempts, so I can dynamically check/support Bluetooth tethering network communication.
First I have two Samsung S4s (running CyanogenMod 10.2, which is Android 4.3.1 based) which I can pair just fine. If I set one device to Bluetooth tether, when the other connects, a new bt-pan network interface is created and DHCP is used to assign IPs. I confirmed this using iwconfig and ifconfig in shell.
I have the following perms in my app: (there's more, I'm just pointing out the BT perms I added)
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
Here's my Service's onCreate where I set my IntentFilters: (note I've got Toasts here, but I was working with Logging originally)
#Override
public void onCreate() {
super.onCreate();
...
this.mLocalBroadcastManager = LocalBroadcastManager.getInstance(this);
IntentFilter filter = new IntentFilter();
filter.addAction(BluetoothDevice.ACTION_FOUND);
filter.addAction(BluetoothDevice.ACTION_ACL_CONNECTED);
filter.addAction(BluetoothDevice.ACTION_ACL_DISCONNECTED);
filter.addAction(BluetoothDevice.ACTION_ACL_DISCONNECT_REQUESTED);
mLocalBroadcastManager.registerReceiver(mMessageReceiver, filter);
}
Here's my BroadcastReceiver implementation:
private BroadcastReceiver mMessageReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if(action.equals(BluetoothDevice.ACTION_FOUND)) {
Toast.makeText(getApplicationContext(), "BT found", Toast.LENGTH_SHORT).show();
} else if(action.equals(BluetoothDevice.ACTION_ACL_CONNECTED)) {
Toast.makeText(getApplicationContext(), "BT Connected",
} else if(action.equals(BluetoothDevice.ACTION_ACL_DISCONNECTED)) {
Toast.makeText(getApplicationContext(), "BT Disconnected", Toast.LENGTH_SHORT).show();
} else
Toast.makeText(getApplicationContext(), "BT Disconnect requested", Toast.LENGTH_SHORT).show();
}
}
}
Now, when I turn Bluetooth off/on, connect/disconnect to a paired device, nothing fires. I've payed around with the devices from both ends. Nothing is broadcast.
Anyone have a suggestion? I really need to receive these bluetooth events. Please don't point to another post/site with the same perms and intent filters. Thanks.

I have a very similar code which works, the only major difference i found was this:
mLocalBroadcastManager.registerReceiver(mMessageReceiver, filter);
i beleive that registerReceiver should be called from the context you want to get intents to.
try calling the method from this. i.e remove the mLocalBroadcastManager like:
registerReceiver(mMessageReceiver, filter);

If you Register the Receiver on the Manifest instead of the Activity, you can receive broadcasts even if you do not have the app opened, you can do this:
<receiver android:name=".BluetoothReceiver" >
<intent-filter>
<action android:name="android.bluetooth.device.action.ACL_CONNECTED" />
<action android:name="android.bluetooth.device.action.BOND_STATE_CHANGED" />
</intent-filter>
</receiver>

Stopping a service when the USB device is unplugged

I want to stop a running service when a usb is unplugged.
inside my activity onCreate I check the intent for its action
if (getIntent().getAction().equals(UsbManager.ACTION_USB_DEVICE_DETACHED)) {
Log.d(TAG, "************** USB unplugged stopping service **********");
Toast.makeText(getBaseContext(), "usb was disconneced", Toast.LENGTH_LONG).show();
stopService(new Intent(this, myService.class));
} else {
init();
}
And inside my manifest I have another intent filter
<intent-filter>
<action android:name="android.hardware.usb.action.USB_DEVICE_DETACHED" />
</intent-filter>
And this intent filter as well which is being called.
<intent-filter>
<category android:name="android.intent.category.DEFAULT" />
<action android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED" />
</intent-filter>
But the detach is not being called.

Hmmm.. ACTION_USB_DEVICE_DETACHED is fired when a USB device (not the cable) is detached from the phone/tablet. This is not something you want.
I do not know if there is a straight forward API for detecting USB cable connections, but you can use ACTION_POWER_CONNECTED and ACTION_POWER_DISCONNECTED to accomplish your goal.
Use following filters for your receiver:
<intent-filter>
<action android:name="android.intent.action.ACTION_POWER_CONNECTED"/>
<action android:name="android.intent.action.ACTION_POWER_DISCONNECTED"/>
</intent-filter>
And in your receiver, you can check the state and implement the logic you want:
public class MyReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
switch(intent.getIntExtra(BatteryManager.EXTRA_PLUGGED, -1)) {
case 0:
// The device is running on battery
break;
case BatteryManager.BATTERY_PLUGGED_AC:
// Implement your logic
break;
case BatteryManager.BATTERY_PLUGGED_USB:
// Implement your logic
break;
case BATTERY_PLUGGED_WIRELESS:
// Implement your logic
break;
default:
// Unknown state
}
}
}

You need to register a BroadcastReceiver
BroadcastReceiver receiver = new BroadcastReceiver() {
public void onReceive(Context context, Intent intent) {
if(intent.getAction().equals(UsbManager.ACTION_USB_DEVICE_DETACHED)) {
Log.d(TAG, "************** USB unplugged stopping service **********");
Toast.makeText(getBaseContext(), "usb was disconneced",
Toast.LENGTH_LONG).show();
stopService(new Intent(this, myService.class));
}
};
IntentFilter filter = new IntentFilter();
filter.addAction(UsbManager.ACTION_USB_DEVICE_DETACHED);
registerReceiver(receiver, filter);

Activity handle when screen unlocked

So I have my onResume command restarting a stopped thread which runs my game loop.
This works perfectly for resuming the app when closed by home button or by focusing on another app.
However, when you turn the screen off then on again, the activities onResume command fires right away before screen is unlocked. I need my activity to know when the screen is unlocked so it can restart the thread at the appropriate time.
Has anyone had this happen before?

for detect screen on and screen off register a broadcast reciver like:
AndroidManifest.xml:
<receiver android:name="receiverScreen">
<intent-filter>
<action android:name="android.intent.action.SCREEN_ON" />
<action android:name="android.intent.action.SCREEN_OFF" />
<action android:name="android.Intent.ACTION_USER_PRESENT" />
</intent-filter>
</receiver>
In Activity or Service:
try {
IntentFilter filter = new IntentFilter(Intent.ACTION_SCREEN_ON);
filter.addAction(Intent.ACTION_SCREEN_OFF);
filter.addAction(Intent.ACTION_USER_PRESENT);
BroadcastReceiver mReceiver = new receiverScreen();
registerReceiver(mReceiver, filter);
} catch (Exception e) {
}
receiver code where System inform you if Screen on/off happen:
public class receiverScreen extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
if (intent.getAction().equals(Intent.ACTION_SCREEN_ON)){
}
if (intent.getAction().equals(Intent.ACTION_SCREEN_OFF)){
}
if (intent.getAction().equals(Intent.ACTION_USER_PRESENT)){
}
}
}