I am writing a program which respond when a new process got start.
private final BroadcastReceiver mBatInfoReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context arg0, Intent intent) {
// what to write here
}
};
I do not know that what to write instead of comments to get processes info.
thanks.
You can't monitor process starts using a BroadcastReceiver. You should look at this: you would have to run it in a loop, but that's probably your best bet.
Related
As a Unity3D developer, I've created an application and exported it to Android Studio. My client is asking me to make this app go back to foreground after 10 seconds of user's inactivity (in case the user opens another app). I've tried to create a service that is started on the OnPause function of my UnityPlayerActivity. Then the service would detect the user's inactivity and launch my app again (putting it back to foreground). First I've only tried to use Time.Schedule to launch my app after 10 seconds no matter what, but everytime the application is paused (goes to background), it starts the service and then it crashes. The question is: is there a simple way to do this? I'm not an Android Java Developer (only know the basics) and I'm struggling with this part .
I'm trying to create this Service and then I try to start it from the onPause() function in my activity. When I pause the app on my phone the app crashes. Can anyone tell me if I'm on the right way and, please, help me?
public class ReturnToForeground extends Service {
public ReturnToForeground() {
}
// constant
public static final long NOTIFY_INTERVAL = 10 * 1000; // 10 seconds
// run on another Thread to avoid crash
private Handler mHandler = new Handler();
// timer handling
private Timer mTimer = null;
Intent intent = new Intent(this, UnityPlayerActivity.class);
#Override
public IBinder onBind(Intent intent) {
return null;
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
// cancel if already existed
if (mTimer != null) {
mTimer.cancel();
} else {
// recreate new
mTimer = new Timer();
}
// schedule task
mTimer.scheduleAtFixedRate(new TimeDisplayTimerTask(), 0, NOTIFY_INTERVAL);
return super.onStartCommand(intent, flags, startId);
}
class TimeDisplayTimerTask extends TimerTask {
#Override
public void run() {
// run on another thread
mHandler.post(new Runnable() {
#Override
public void run() {
// do action
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
intent.setAction(Intent.ACTION_MAIN);
intent.addCategory(Intent.CATEGORY_LAUNCHER);
startActivity(intent);
}
});
}
}
}
Make a timer for when the app is in the onPause(), when the timer reaches 10 seconds you should pass an intent which will make your app active again (let's say taking the user back to the main view). You can save the current data of your app in something like shared preffs, so that information wont be lost in most situations.
In many cases this problem appears when a resource which you are trying to reload is not active anymore inside the application.
From the info you have shared it seems like you are not starting the service correctly. It would be nice if you can add a crash log so that we can debug it and see where is the problem.
I have a service declared in manifest like
<service android:name=".services.ScreenOnService" android:process="#string/screenProcess"/>
all the service does is registering for Screen_on broadcast (As i always need the information that the Screen was turned on and not only if my app is running)
#Nullable
#Override
public IBinder onBind(Intent intent)
{
return null;
}
#Override
public int onStartCommand(Intent intent, int flags, int startId)
{
//All this service has to do is register for the screen on broadcast
//as this one can't be registere in manifest and the ACTION_USER_PRESENT is
//not guaranteed to be fired. (E.g. if no lock screen is used)
IntentFilter filter = new IntentFilter(Intent.ACTION_SCREEN_ON);
registerReceiver(screenEventReceiver,filter);
return START_STICKY;
}
#Override
public void onDestroy()
{
unregisterReceiver(screenEventReceiver);
super.onDestroy();
}
I start the service from my Application onCreate
#Override
public void onCreate() {
super.onCreate();
if(!isScreenOnServiceAlreadyRunning())
{
//Start the screen on service
Intent screenOnService = new Intent(this, ScreenOnService.class);
startService(screenOnService);
}
}
Everything is fine as long as the app is running. If I kill the app, the service in it's own process is also killed and I don't get why.
I found a promising article here http://fabcirablog.weebly.com/blog/creating-a-never-ending-background-service-in-android and hoped the best but even if I do this and send a broadcast, it will not work.
Why does the service stop working if the app is killed? I assumed it will keep running, as it's in it's own process. If what I want is not realisable with my approach, what's the best way to do so?
Thanks already.
#Hardcore_Graverobber I think you should start the service as a separate process,
please refer this tutorial
http://www.vogella.com/tutorials/AndroidServices/article.html
I'd like to somehow stop Bluetooth from changing the volumes when it connects and disconnects. I just want them to stay where they are. How could I go about this? I know how to run services and I can set up listeners, but the following has no effect:
final IntentFilter bluetoothConnectedFilter = new IntentFilter( BluetoothDevice.ACTION_ACL_CONNECTED );
bluetoothConnectedReceiver = new BroadcastReceiver() {
#Override
public void onReceive( Context context, Intent intent ) {
// Change volumes programmatically (code already tested and working elsewhere)
}
};
Thanks for any help.
PROBLEM
As topic mention, I don't know why getBooleanExtra() java.lang.NullPointerException.
I understand that sometimes intent may not contains extras.
However, from the below code as you can see there is a default value for each getBooleanExtra() which is false.
So, that's the reason why I don't understand. please advice. thx!
SOME CODE FROM MY SERVICE CLASS
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
Log.d("onStartCommand()->","Intent Service.... " + intent);
final boolean SLEEP_MODE_ON = intent.getBooleanExtra("SLEEP_MODE_ON",false);
final boolean SLEEP_MODE_OFF = intent.getBooleanExtra("SLEEP_MODE_OFF",false);
Thread thread = new Thread(new Runnable(){
#Override
public void run() {
connectIfNecessary();
if (SLEEP_MODE_ON){
doSleepMode_on();
} else if (SLEEP_MODE_OFF) {
doSleepMode_off();
}
}
});
thread.start();
return START_STICKY;
}
EDIT as some ask Where I call My service?? First, from activity. Second, from broadcastReceiver
ACTIVITY in onCreate()
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//Remove title bar
this.requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.main);
startService(new Intent(this,mqttPushService.class)); //Setup MQTT Service
}//END of onCreate()
BroadcastReceiver
public class SleepModeReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
Intent sleepModeIntent;
int broadcastID = intent.getIntExtra("BROADCAST_ID",0);
switch (broadcastID) {
case DataManager.BROADCAST_ID_SLEEP_MODE_START :
sleepModeIntent = new Intent(context, mqttPushService.class);
sleepModeIntent.putExtra("SLEEP_MODE_ON",true);
context.startService(sleepModeIntent);
break;
case DataManager.BROADCAST_ID_SLEEP_MODE_STOP :
sleepModeIntent = new Intent(context, mqttPushService.class);
sleepModeIntent.putExtra("SLEEP_MODE_OFF",true);
context.startService(sleepModeIntent);
break;
}
}
}
I ran into this recently. The issue is that even services can be killed and restarted by the system , thats why you have START_STICKY. Unlike when you start the service and you pass a valid intent, when the system restarts the service, the intent is null. I just check for a null intent before trying to extract any extras.
Here is the link to the official android developers blog.
http://android-developers.blogspot.com/2010/02/service-api-changes-starting-with.html
and here is the paragraph which basically says what I say above
START_STICKY is basically the same as the previous behavior, where the service is left "started" and will later be restarted by the system. The only difference from previous versions of the platform is that it if it gets restarted because its process is killed, onStartCommand() will be called on the next instance of the service with a null Intent instead of not being called at all. Services that use this mode should always check for this case and deal with it appropriately.
I'm android beginner so please be easy on me. I'm doing some "exercises" and i'm writing simple app which will tell RSSI strength of home wifi network. Getting that number is pretty easy, but updating it and showing that on screen it's a little more complicated as i thought.
First this is my onCreate Activity. In this activity i'm launching another android component - Service. Because the code will run in background (i know i could use thread or something else, but this is for "practice" sake, and i have a few ideas what to do with this app, while running service and not interacting with UI )
public class MainActivity extends Activity {
TextView wifi_check;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
referenceViews();
startService(new Intent(this, CheckingWifiService.class));
//wifi_check.setText(""+getIntent().getExtras().getInt("RSSI"));
}
private void referenceViews() {
wifi_check = (TextView) findViewById(R.id.wifiCheck_TV);
}
}
Because my code will run every second or so, i will use TimerTask for this purpose. And here is my TimerTask class, which includes run() method, and code for executing inside
public class TimerTsk extends TimerTask {
Context act;
WifiManager wifiMan;
WifiInfo info;
Bundle sendInfo;
Intent intent;
int rssi;
public TimerTsk(Context context) {
act = context;
}
#Override
public void run() {
intent = new Intent();
sendInfo = new Bundle();
wifiMan = (WifiManager) act.getSystemService(Activity.WIFI_SERVICE);
info = wifiMan.getConnectionInfo();
rssi = info.getRssi();
Log.d("WORKED", "RUNNING SUCESSFULLY");
// i want to send info to my activity
sendInfo.putInt("RSSI", rssi);
intent.putExtras(sendInfo);
}
}
From this class , i want to send result of RSSI to my activity and then update a text. But when i call this code below, on activity i always get NullPointerException.
wifi_check.setText(""+getIntent().getExtras().getInt("RSSI"));
To be honest i had hard time figuring out which part of code is throwing an exepction. And i found that more exactly, this part of code is throwing an exepction.
getInt("RSSI")
Overall i see that service is running, because in my LOGCAT i see a message that i create with Log.d in TimerTsk class.
Any ideas why is this happening?
Here is my service class:
public class CheckingWifiService extends Service{
int rssi;
Timer time;
TimerTsk ttsk;
#Override
public IBinder onBind(Intent intent) {
return null;
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
time = new Timer();
time.schedule(new TimerTsk(getApplicationContext()), 500);
return START_STICKY;
}
}
Here is my LogCat:
I see a common mistake. Don't do this:
sendInfo.putInt("RSSI", rssi);
intent.putExtras(sendInfo); // This adds a Bundle to your existing Bundle!
You are creating an Intent, with a Bundle of extras, with a Bundle that holds rssi. Leave out this unnecessary Bundle:
intent.putExtras("RSSI", rssi);
Now in your next Activity you can use:
getIntent().getIntExtra("RSSI", 0);
However you should always check to make sure there aren't any surprise null variables:
Intent in = getIntent();
if(in != null) {
int rssi = in.getIntExtra("RSSI", -1);
if(rssi < 0)
wifi_check.setText(""+rssi);
else
wifi_check.setText("Unknown");
}
is your activity starting? I don't see any call to startActivity(). In any case as mentioned by Sam you just need to call putExtra for your intent. don't forget to call
is your activity starting? I don't see any call to startActivity(). In any case as mentioned by Sam you just need to call putExtra for your intent. don't forget to call
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
you need to put this flag when start activies from background