Develop Reference

Getting NULL in context while auto restart with BROADCAST RECEIVER in Android app

I am developing android application which need auto restart when restart device for that I am using broadcast receiver with action BOOT_COMPLETED.
Broadcast receiver is receiving message when I am restarting device but in restart method I want to start main activity for that I used Intent but in onReceive method of receiver I am getting null context so I am unable to restart main Activity.
Below is code for that.
MainActivity.java
private Object activity;
private TextView tvImeiNum;
private BroadcastReceiver rebootreceiver;
private IntentFilter filter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tvImeiNum = (TextView)findViewById(R.id.tv_imeinum);
filter = new IntentFilter();
filter.addAction(Intent.ACTION_BOOT_COMPLETED);
filter.addAction(Intent.ACTION_REBOOT);
rebootreceiver = new BootUpReceiver(MainActivity.this);
LocalBroadcastManager.getInstance(this).registerReceiver(rebootreceiver,
filter);//registering receiver
generateUniqueCode();
}
BootupReceiver.java
public class BootUpReceiver extends BroadcastReceiver {
MainActivity ma;
public BootUpReceiver(MainActivity maContext){
ma=maContext;
}
public BootUpReceiver(){
}
#RequiresApi(api = Build.VERSION_CODES.M)
#Override
public void onReceive(Context context, Intent intent) {
if (intent.getAction().equals("android.intent.action.BOOT_COMPLETED")) {
Log.d("TAG REBOOT", "onReceive: " + intent);
Log.d("Reboot complete", "connection");
GlobalTool.restartApplication(context);
}
}
}
GlobalTool.java
public class GlobalTool {
#RequiresApi(api = Build.VERSION_CODES.M)
public static void restartApplication(Context context) {
Log.d("IN App restart:", "");
Log.d("TAG", "restartApplication: ");
if(context != null)
{
Log.d("TAG NULL", "restartApplication: ");
Intent mainIntent = new Intent(context, MainActivity.class);
AlarmManager alarmMgr = (AlarmManager)
context.getSystemService(ALARM_SERVICE);
TaskStackBuilder stackBuilder = TaskStackBuilder.create(context);
stackBuilder.addNextIntent(mainIntent);
PendingIntent pendingIntent = stackBuilder.getPendingIntent(0,
PendingIntent.FLAG_UPDATE_CURRENT);
long alarmTime = System.currentTimeMillis() + (1 * 1000);
alarmMgr.setExact(AlarmManager.RTC_WAKEUP, alarmTime, pendingIntent);
Log.d("TAG", "restartApplication: 111");
Log.d("TAG", "restartApplication: 111");
}
else {
Intent mainIntent = new Intent(context, MainActivity.class);
AlarmManager alarmMgr = (AlarmManager)
context.getSystemService(ALARM_SERVICE);
TaskStackBuilder stackBuilder = TaskStackBuilder.create(context);
stackBuilder.addNextIntent(mainIntent);
PendingIntent pendingIntent = stackBuilder.getPendingIntent(0,
PendingIntent.FLAG_UPDATE_CURRENT);
long alarmTime = System.currentTimeMillis() + (1 * 1000);
alarmMgr.setExact(AlarmManager.RTC_WAKEUP, alarmTime, pendingIntent);
Log.d("TAG", "restartApplication: 111");
Log.d("TAG", "restartApplication: 111");
}
}
}
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
package="com.example.kioskappdemo">
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission
android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
<application
android:name="KioskApplication"
android:allowBackup="true"
android:dataExtractionRules="#xml/data_extraction_rules"
android:fullBackupContent="#xml/backup_rules"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/Theme.KioskAppDemo"
tools:targetApi="31"
tools:ignore="Instantiatable">
<service
android:name=".RebootService"
android:enabled="true"
android:exported="true"></service>
<activity
android:name=".MainActivity"
android:exported="true"
android:screenOrientation="landscape"
android:theme="#style/Theme.AppCompat.NoActionBar">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category
android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<receiver
android:name=".Activity.BootUpReceiver"
android:enabled="true"
android:exported="true">
<intent-filter >
<action
android:name="android.intent.action.BOOT_COMPLETED" />
<action android:name="android.intent.action.REBOOT" />
<action
android:name="android.intent.action.QUICKBOOT_POWERON" />
<action android:name="com.reboot.test" />
<action
android:name="android.intent.action.TIMEZONE_CHANGED" />
<action
android:name="android.intent.action.DATE_CHANGED" />
</intent-filter>
</receiver>
</application>
</manifest>

Some you code improvements:
Don't put context to Brodcast Receiver constructor. Use the Context from onReceive method
public class BootUpReceiver extends BroadcastReceiver {
public BootUpReceiver(){
//TODO log
}
...
You should not use LocalBroadcastManager::registerReceiver call. If Broadcast receiver is added to AndroidManifest then it will be started by the system.
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
<receiver
android:name=".activity.BootUpReceiver"
android:enabled="true"
android:exported="true"
android:permission="android.permission.RECEIVE_BOOT_COMPLETED">
<intent-filter >
<action android:name="android.intent.action.BOOT_COMPLETED" />
</intent-filter>
</receiver>
Don't use CamelCase for package names (use .activity.BootUpReceiver insetad .Activity.BootUpReceiver)

How to set an alarm even when app is killed? (Android 9)

I have implemented a simple app in order to set an alarm (e.g. 7.00pm) every minute. When running this app at emulator, which android version is 8.1, it runs successfully in background even the app is killed. But when running the same app at my android 9 when app is killed it stops running in background.
public class MainActivity extends AppCompatActivity {
private Context context;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
this.context = this;
ComponentName receiver = new ComponentName(this, AlarmReceiver.class);
PackageManager pm = this.getPackageManager();
pm.setComponentEnabledSetting(receiver, PackageManager.COMPONENT_ENABLED_STATE_ENABLED, PackageManager.DONT_KILL_APP);
Intent alarm = new Intent(this.context, AlarmReceiver.class);
alarm.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_MULTIPLE_TASK | Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED);
boolean alarmRunning = (PendingIntent.getBroadcast(this.context, 0, alarm, PendingIntent.FLAG_NO_CREATE) != null);
if(alarmRunning == false) {
PendingIntent pendingIntent = PendingIntent.getBroadcast(this.context, 0, alarm, 0);
AlarmManager alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, SystemClock.elapsedRealtime(), 60000, pendingIntent);
}
}
Manifest.xml
<?xml version="1.0" encoding="utf-8"?>
<uses-permission android:name="com.android.alarm.permission.SET_ALARM" />
<uses-permission android:name="com.android.alarm.permission.FLAG_ACTIVITY_NEW_TASK" />
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<service android:name=".BackgroundService" />
<receiver android:name=".AlarmReceiver"
android:enabled="true"
android:exported="true"
android:label="RestartServiceWhenStopped">
<intent-filter>
<action android:name="android.intent.action.BOOT_COMPLETED"/>
<action android:name="android.bluetooth.adapter.action.STATE_CHANGED"/>
<action android:name="android.intent.action.QUICKBOOT_POWERON" />
<action android:name="android.intent.action.TIME_SET" />
</intent-filter>
</receiver>
</application>
AlertReceiver.java
public class AlarmReceiver extends BroadcastReceiver {
private static int minutes=0;
#Override
public void onReceive(Context context, Intent intent) {
Log.e("Service",String.valueOf(Calendar.getInstance().getTimeInMillis()));
intent = new Intent(AlarmClock.ACTION_SET_ALARM);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_MULTIPLE_TASK);
minutes++;
intent.putExtra(AlarmClock.EXTRA_HOUR, 7);
intent.putExtra(AlarmClock.EXTRA_MINUTES, minutes);
context.startActivity(intent);
/*Intent background = new Intent(context, BackgroundService.class);
context.startService(background);*/
}
Do you have any idea how to fix this? Thank you in advance!

Android service on device boot works once

System tested: Android 6.0 Device Alcatel POP4.
I have a task - run parse function white app is run, suspended, exited and device reboot.
Issue: when I reboot device the function works only once, and then stops. If I reopen app, then close it, the function will work again in background service. If I reboot device it will be called just once again. No errors given =(
Need help!
public class ParseIntentService extends IntentService {
MainActivity main = new MainActivity();
Context context;
public ParseIntentService() {
super("ParseIntentService");
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
return super.onStartCommand(intent, flags, startId);
}
#Override
protected void onHandleIntent(Intent intent) {
main.serviceRun(this);
WakefulBroadcastReceiver.completeWakefulIntent(intent);
}
}
public class NotificationAlarmReceiver extends BroadcastReceiver {
public static final int REQUEST_CODE = 10000;
public static final String ACTION = "com.falcode.gratsme";
public NotificationAlarmReceiver() {
}
#Override
public void onReceive(Context context, Intent intent) {
Intent i = new Intent(context, ParseIntentService.class);
context.startService(i);
}
}
public class BootBroadcastReceiver extends WakefulBroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
// Launch the specified service when this message is received
Intent startServiceIntent = new Intent(context, ParseIntentService.class);
startWakefulService(context, startServiceIntent);
}
}
public void startAlarm() {
Intent intent = new Intent(getApplicationContext(), NotificationAlarmReceiver.class);
// Create a PendingIntent to be triggered when the alarm goes off
final PendingIntent pIntent = PendingIntent.getBroadcast(this, NotificationAlarmReceiver.REQUEST_CODE,
intent, PendingIntent.FLAG_UPDATE_CURRENT);
// Setup periodic alarm every 5 seconds
long firstMillis = System.currentTimeMillis(); // alarm is set right away
AlarmManager alarm = (AlarmManager) this.getSystemService(Context.ALARM_SERVICE);
// First parameter is the type: ELAPSED_REALTIME, ELAPSED_REALTIME_WAKEUP, RTC_WAKEUP
// Interval can be INTERVAL_FIFTEEN_MINUTES, INTERVAL_HALF_HOUR, INTERVAL_HOUR, INTERVAL_DAY
alarm.setInexactRepeating(AlarmManager.RTC_WAKEUP, firstMillis,
REQUEST_PERIOD, pIntent);
}
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.falcode.sovkombank">
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
<uses-permission android:name="android.permission.WAKE_LOCK" />
<application
android:allowBackup="true"
android:fullBackupContent="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/AppTheme">
<activity
android:name=".MainActivity"
android:screenOrientation="portrait">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<service
android:name=".ParseIntentService"
android:enabled="true"
android:exported="false" />
<receiver
android:name=".NotificationAlarmReceiver"
android:process=":remote" />
<receiver
android:name=".BootBroadcastReceiver"
android:enabled="true"
android:permission="android.permission.RECEIVE_BOOT_COMPLETED">
<intent-filter>
<action android:name="android.intent.action.BOOT_COMPLETED" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</receiver>
</application>
</manifest>

Alarm Manager Example does not work

I am trying to follow the example given here on running some code in fixed time intervals. I used the code in this example (setting the waiting time to 1 minute instead), compiled it, started in on my phone, stopped the application on the phone, and waited for several minutes.
However, no Toast was shown and neither any log-entry. I also notice that the Service.onStart seems depreciated.
Is something missing in the example? Do I need to register something when the main activity of the app is started? Or call it from somewhere else in my app? Or maybe something is wrong in the manifest?
AndroidManifest.xml:
<?xml version="1.0" encoding="utf-8"?>
<manifest
xmlns:android="http://schemas.android.com/apk/res/android"
package="com.mypackage.test" >
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.WAKE_LOCK" />
<application>
android:allowBackup="true"
android:icon="#mipmap/stoxx"
android:label="#string/app_name"
android:supportsRtl="true"
android:theme="#style/Theme.AppCompat.Light" >
<activity
android:name=".MainActivity"
android:label="#string/app_name"
android:theme="#style/AppTheme.NoActionBar" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".NewEntryActivity"
android:label="#string/menu_add"
android:theme="#style/AppTheme.NoActionBar"
/>
<activity
android:name=".UserSettingActivity"
android:label="#string/menu_add"
android:theme="#style/AppTheme.NoActionBar"
/>
<receiver
android:process=":remote"
android:name=".Alarm">
</receiver>
</application>
</manifest>

You forgot to include service in your Manifest. Here is all this project that works for me, check it.
Here is my manifest:
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.alarmmanager.just_me.alarmmanager">
<uses-permission android:name="android.permission.WAKE_LOCK"/>
<application android:allowBackup="true" android:label="#string/app_name"
android:icon="#mipmap/ic_launcher" android:supportsRtl="true"
android:theme="#style/AppTheme">
<activity android:name=".MainActivity"
android:label="#string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<receiver android:process=":remote" android:name=".Alarm"/>
<service android:name=".MyService"/>
</application>
Here is Alarm:
public class Alarm extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent)
{
PowerManager pm = (PowerManager) context.getSystemService(Context.POWER_SERVICE);
PowerManager.WakeLock wl = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "");
wl.acquire();
// Put here YOUR code.
Toast.makeText(context, "com.alarmmanager.just_me.alarmmanager.Alarm !!!!!!!!!!", Toast.LENGTH_LONG).show(); // For example
wl.release();
}
public void SetAlarm(Context context)
{
AlarmManager am =( AlarmManager)context.getSystemService(Context.ALARM_SERVICE);
Intent i = new Intent(context, Alarm.class);
PendingIntent pi = PendingIntent.getBroadcast(context, 0, i, 0);
am.setRepeating(AlarmManager.RTC_WAKEUP, System.currentTimeMillis(), 1000 * 5, pi); // Millisec * Second
}
public void CancelAlarm(Context context)
{
Intent intent = new Intent(context, Alarm.class);
PendingIntent sender = PendingIntent.getBroadcast(context, 0, intent, 0);
AlarmManager alarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
alarmManager.cancel(sender);
}}
Here is service:
public class MyService extends Service
{
Alarm alarm = new Alarm();
public void onCreate()
{
super.onCreate();
}
#Override
public int onStartCommand(Intent intent, int flags, int startId)
{
Log.d("!~!", "Service started.");
alarm.SetAlarm(this);
return START_STICKY;
}
#Override
public void onStart(Intent intent, int startId)
{
alarm.SetAlarm(this);
}
#Override
public IBinder onBind(Intent intent)
{
return null;
}
}
And the last one MainActivity:
public class MainActivity extends Activity{
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Intent intent = new Intent(this, MyService.class);
startService(intent);
}
}

Alarm doesn't trigger the AlarmReveicer

I am coding a simple alarm test in android, but as mentionned in the title the AlarmReceiver isn't triggered !
i sought here for the solution but none of them worked since my code seems to be correct ...
here is my code :
public class AlarmActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_alarm);
Button salarm = (Button) findViewById(R.id.salarm);
final AlarmManager alarmManager = (AlarmManager)getSystemService(ALARM_SERVICE);
Intent i = new Intent(AlarmActivity.this,AlarmReceiver.class);
final PendingIntent pi = PendingIntent.getBroadcast(getApplicationContext(), 0, i, 0);
salarm.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
alarmManager.set(AlarmManager.RTC_WAKEUP, SystemClock.elapsedRealtime()+(1000*5), pi);
Toast.makeText(getApplicationContext(), "Alarm set, wait 5 sec", Toast.LENGTH_SHORT).show();
}
});
}
Manifest file :
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.androidtest3"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="18" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name="com.androidtest3.MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name="AlarmActivity"/>
<receiver
android:exported = "true"
android:name = "AlarmReceiver">
</receiver> <!-- <receiver android:name="AlarmReceiver"/> aurait fait l'affaire -->
</application>
</manifest>
AlarmReceiver Class :
public class AlarmReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
Toast.makeText(context, "pending intent received !", Toast.LENGTH_SHORT).show();
}
}
it would help if you could explain the any solution you suggest.
thanx

It's likely not happening because the time value is incorrect. If you are going to use RTC_WAKEUP type alarms, get the time using System.currentTimeMillis() plus your additional time. Right now you're using elapsed time, which is not the same as RTC wall clock time.