How to schedule a task on Android

Question

I have a database that I need to delete on a specific day, how can I complete this task? I found this:

timer = new Timer(); timer.scheduleAtFixedRate(new TimerTask() { synchronized public void run() { \\ here your todo; } }}, TimeUnit.MINUTES.toMillis(1), TimeUnit.MINUTES.toMillis(1)); 

But I'm not sure if he will “save the task” until the expiration date. Thanks

Answer 1

The AlarmManager class allows you to schedule recurring alarms that will work at specified points in the future. AlarmManager gets the PendingIntent to start when an alarm is scheduled. When an alarm triggered, a registered Intent is broadcast by the Android system, launching the target application, if it is not already running.

Create a class that inherits from BroadcastReceiver. In the onReceive method, which is called when BroadcastReceiver receives an Intent broadcast, we will create code that performs our task.

AlarmReceiver.java

 import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.widget.Toast; public class AlarmReceiver extends BroadcastReceiver { @Override public void onReceive(Context arg0, Intent arg1) { // For our recurring task, we'll just display a message Toast.makeText(arg0, "I'm running", Toast.LENGTH_SHORT).show(); } } 

Then we need to register the BroadcastReceiver in the manifest file. Declare AlarmReceiver in the manifest file.

 <application> . . <receiver android:name=".AlarmReceiver"></receiver> . . </application> 

The following instance variables are included in your calling activity.

 private PendingIntent pendingIntent; private AlarmManager manager; 

In onCreate (), we create an Intent that references our broadcast receive class and uses it in our PendingIntent.

 protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); // Retrieve a PendingIntent that will perform a broadcast Intent alarmIntent = new Intent(this, AlarmReceiver.class); pendingIntent = PendingIntent.getBroadcast(this, 0, alarmIntent, 0); } 

Then we turn on a method that will set up repeated alarms. After setting, the alarm will be triggered after every Xth time, here we take an example of 10 seconds, you can simply calculate this to call it every day.

 public void startAlarm(View view) { manager = (AlarmManager)getSystemService(Context.ALARM_SERVICE); int interval = 10000; manager.setRepeating(AlarmManager.RTC_WAKEUP, System.currentTimeMillis(), interval, pendingIntent); Toast.makeText(this, "Alarm Set", Toast.LENGTH_SHORT).show(); } 

Next, also configure the cancelAlarm () method to stop alarms if necessary.

 public void cancelAlarm(View view) { if (manager != null) { manager.cancel(pendingIntent); Toast.makeText(this, "Alarm Canceled", Toast.LENGTH_SHORT).show(); } } 

Answer 2

To do this, you need to use Alaram Manager, which will call after a certain time.

First you need to declare a broadcast receiver that will receive these alarams

 public class DBActionReceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { // TODO Auto-generated method stub // perform delete operation here } } 

Secondly, now register an alaram manager

 AlarmManager alarms = (AlarmManager)this.getSystemService(Context.ALARM_SERVICE); DBActionReceiver receiver = new DBActionReceiver (); IntentFilter filter = new IntentFilter("ALARM_ACTION"); registerReceiver(receiver, filter); Intent intent = new Intent("ALARM_ACTION"); intent.putExtra("param", "My scheduled action"); PendingIntent operation = PendingIntent.getBroadcast(this, 0, intent, 0); // invoke broadcast after one minute of my app launch alarms.set(AlarmManager.RTC_WAKEUP, System.currentTimeMillis()+(1000 * 60), operation) ;