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)

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);
}
}

Broadcast Receiver not working for me

I have the AlarmMainActivity which broadcasts an intent at a time set by the alarm. And the receiver program AlarmReceiver should catch this intent and send a notification. From the log, I can see that the alarm is being set, but the receiver doesn't start and its not working. Can you look at my code below and please let me know why the BroadcastReceiver is not working. Thanks.
AlarmMainActivity:
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_alarm_main);
Intent alertIntent = new Intent(this, AlarmReceiver.class);
final PendingIntent pendingIntent =
PendingIntent.getBroadcast
(this,1,alertIntent,PendingIntent.FLAG_UPDATE_CURRENT);
final Button alarmButton = (Button)findViewById(R.id.alarm_button);
alarmButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Long alertTime = new
GregorianCalendar().getTimeInMillis()+5*1000;
Log.i(TAG,"Alarm will be sent at : "+ alertTime.toString());
AlarmManager am =
(AlarmManager)getSystemService(Context.ALARM_SERVICE);
am.set(AlarmManager.RTC_WAKEUP,alertTime,pendingIntent );
Log.i(TAG, "Alarm is now set");
}
});
}//oncreate
AlarmReceiver:
public class AlarmReceiver extends BroadcastReceiver{
private static final String TAG = "AlarmReceiver";
private String msgTitle, msgText, msgTicker;
#Override
public void onReceive(Context context, Intent intent) {
Log.i(TAG, "Entered AlarmReceiver()");
msgTitle = "Todays Weather";
msgText = "Its Sunny and Warm";
msgTicker="Alert";
PendingIntent notifyIntent = PendingIntent.getActivity(context,0, new
Intent(context, AlarmMainActivity.class),0);
NotificationCompat.Builder mBuilder = new
NotificationCompat.Builder(context).
setSmallIcon(R.drawable.weather_image).
setTicker(msgTicker).
setContentTitle(msgTitle).
setContentText(msgText).
setDefaults(NotificationCompat.DEFAULT_SOUND).
setAutoCancel(true).
setContentIntent(notifyIntent);
NotificationManager notificationManager =
(NotificationManager)context.getSystemService
(Context.NOTIFICATION_SERVICE);
notificationManager.notify(1,mBuilder.build());
Log.i(TAG,"Notification Sent");
}
AndroidManifest:
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.thirdlaw.alertalarm" >
<uses-permission android:name="com.android.alarm.permission.SET_ALARM"/>
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme"
android:debuggable="true">
<activity
android:name=".AlarmMainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
<receiver android:name="com.thirdlaw.alertalarm.AlarmReceiver">
<intent-filter>
<action android:name="MY_ACTION_STRING"/>
</intent-filter>
</receiver>
</activity>
</application>
</manifest>

Remove the <receiver /> tag out of the <activity /> tag like :
<activity
android:name=".AlarmMainActivity"
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:name="com.thirdlaw.alertalarm.AlarmReceiver">
<intent-filter>
<action android:name="MY_ACTION_STRING"/>
</intent-filter>
</receiver>

Android 4.4.4 Kitkat: Broadcastreceiver not receiving on_boot_completed broadcast

My program is to listen receive_boot_complete broadcast when device completes the boot.
The program is working fine as expected with android 4.0.3, but the same thing is not happening when I am running the code on Android 4.4.4 device.
The broadcastreceiver is not receiving a boot completed broadcast.
Is there anything new for Android 4.4.4? Running it on Moto G.
My code is as below:
AndroidManifest
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.my.app"
android:versionCode="1"
android:installLocation="internalOnly"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="15"
android:targetSdkVersion="19" />
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_INTERNAL_STORAGE" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="com.android.alarm.permission.SET_ALARM" />
<uses-permission android:name="android.permission.INTERNET" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="#string/app_name"
android:excludeFromRecents="true" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<service
android:name=".MyService"
android:label="#string/ser_name"
android:icon="#drawable/serv_ico"
android:enabled="true" />
<receiver
android:name=".BootReceiver"
android:enabled="true"
android:permission="android.permission.RECEIVE_BOOT_COMPLETED" >
<intent-filter>
<action android:name="android.intent.action.BOOT_COMPLETED" />
<action android:name="android.intent.action.QUICKBOOT_POWERON" />
<action android:name="android.intent.action.ACTION_BOOT_COMPLETED" />
</intent-filter>
</receiver>
<receiver
android:name=".AlarmReceiver"
android:enabled="true" >
</receiver>
</application>
BootReceiver
public class BootReceiver extends BroadcastReceiver{
#Override
public void onReceive(final Context context, Intent intent) {
Timer timer = new Timer();
timer.schedule(new TimerTask() {
#Override
public void run() {
// Start alarm manager on boot
// Start service
}
}, 60000);
}
}
AlarmReceiver
public class AlarmReceiver extends BroadcastReceiver {
#Override
public void onReceive(final Context context, Intent intent) {
// Start service
}
}
MainActivity
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Run service on application start
setContentView(R.layout.activity_main);
// Initialize alarm manager application start
PackageManager p = getPackageManager(); // Remove App icon from launcher
p.setComponentEnabledSetting(getComponentName(), PackageManager.COMPONENT_ENABLED_STATE_DISABLED, PackageManager.DONT_KILL_APP);
}
}
AlarmManager
public class Alarm {
public Alarm schedule(Context context) {
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.HOUR_OF_DAY, 20);
calendar.set(Calendar.MINUTE, 15);
calendar.set(Calendar.SECOND, 0);
AlarmManager am = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
Intent intent = new Intent(context, AlarmReceiver.class);
PendingIntent pi = PendingIntent.getBroadcast(context, 0, intent, 0);
am.setRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(),AlarmManager.INTERVAL_DAY, pi);
return null;
}
}

You have to define your receiver with exported = true and enabled = true
<android:name=".BootReceiver"
android:enabled="true"
android:exported="true"
android:permission="android.permission.RECEIVE_BOOT_COMPLETED" />

This might be because of a bug in Android 4.4.4 r1/r2
See
Bug in Android KitKat

Launching an intent from BroadcastReceiver?

Hi this is my first question on stackoverflow and I'm a beginner on Android programming. I've looked through numerous webpages but can't seem to find my solution. What I'm trying to do is launch a new activity when a button is pressed after 5 seconds with a BroadcastReceiver. This activity will have a new UI with graphics and sounds (eventually). I got the BroadcastReceiver to work but the program crashes when it tries to launch the new intent. What am I doing wrong?
The method in my MainActivity class:
public void setAlarm(){
Intent intent = new Intent(MainActivity.this, MyBroadcastReceiver.class);
PendingIntent pendingIntent = PendingIntent.getBroadcast(MainActivity.this, 0, intent, 0);
AlarmManager alarmManager = (AlarmManager)getSystemService(ALARM_SERVICE);
alarmManager.set(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis() + 5 * 1000, pendingIntent);
}
My BroadcastReceiver class:
public class MyBroadcastReceiver extends BroadcastReceiver{
#Override
public void onReceive(Context context, Intent intent){
Intent intent1 = new Intent(context, ShakeActivity.class);
context.startActivity(intent1);
Toast.makeText(context, "Broadcast works", Toast.LENGTH_LONG).show();
}
}
Manifest file:
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.shakecounter"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="19" />
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name="com.example.shakecounter.MainActivity"
android:label="#string/app_name"
android:screenOrientation="portrait" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name="com.example.shakecounter.ShakeActivity"
android:label="#string/title_activity_shake" >
</activity>
<receiver android:name="com.example.shakecounter.MyBroadcastReceiver">
</receiver>
</application>
</manifest>

Intent intent1 = new Intent(context, ShakeActivity.class);
intent1.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(intent1);

Try this one.
Intent iAlarm = new Intent( mcontext1, Alertdialogclass.class );
iAlarm.addFlags(Intent.FLAG_FROM_BACKGROUND);
iAlarm.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
mcontext1.startActivity(iAlarm);

You have to put the flag FLAG_ACTIVITY_NEW_TASK when You are starting from inside a Receiver:
Intent intent1 = new Intent(context, ShakeActivity.class);
intent1.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(intent1);
If there is another problem, You should post the logcat.