Update Widget in onReceive() method

In my previous exercise of App Widget (Refer "App Widget using Alarm Manager" and "Cancel Alarm Service in onDisabled()"), Alarm Service was used t trigger onReceive() method of AppWidgetProvider object. It simple prompt user with a Toast only, without update widgets. This exercise, onReceive() method will update widgets.

In order to retrieve the list of appWidgetIds, the following code can be used:

ComponentName thisAppWidget = new ComponentName(context.getPackageName(), HelloWidgetProvider.class.getName());
int[] appWidgetIds = appWidgetManager.getAppWidgetIds(thisAppWidget);

then call onUpdate() method to update all widgets.

HelloWidgetProvider.java

package com.exercise.HelloWidget;

import java.text.SimpleDateFormat;
import java.util.Date;

import android.app.AlarmManager;
import android.app.PendingIntent;
import android.appwidget.AppWidgetManager;
import android.appwidget.AppWidgetProvider;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.widget.RemoteViews;
import android.widget.Toast;

public class HelloWidgetProvider extends AppWidgetProvider {

static AlarmManager myAlarmManager;
static PendingIntent myPendingIntent;

private static SimpleDateFormat formatter = new SimpleDateFormat("dd MMM yyyy  hh:mm:ss a");
static String strWidgetText = "";

public static String MY_WIDGET_UPDATE = "MY_OWN_WIDGET_UPDATE";

@Override
public void onReceive(Context context, Intent intent) {
 // TODO Auto-generated method stub
 super.onReceive(context, intent);

 if(MY_WIDGET_UPDATE.equals(intent.getAction())){
 
   Bundle extras = intent.getExtras();
   if(extras!=null) {
    AppWidgetManager appWidgetManager = AppWidgetManager.getInstance(context);
    ComponentName thisAppWidget = new ComponentName(context.getPackageName(), HelloWidgetProvider.class.getName());
    int[] appWidgetIds = appWidgetManager.getAppWidgetIds(thisAppWidget);

    onUpdate(context, appWidgetManager, appWidgetIds);
   }
 
  //Toast.makeText(context, "onReceiver()", Toast.LENGTH_LONG).show();
 }
}

@Override
public void onDeleted(Context context, int[] appWidgetIds) {
 // TODO Auto-generated method stub
 //super.onDeleted(context, appWidgetIds);
 Toast.makeText(context, "onDeleted()", Toast.LENGTH_LONG).show();
}

@Override
public void onDisabled(Context context) {
 // TODO Auto-generated method stub
 //super.onDisabled(context);

 myAlarmManager.cancel(myPendingIntent);

 Toast.makeText(context, "onDisabled()", Toast.LENGTH_LONG).show();
}

@Override
public void onEnabled(Context context) {
 // TODO Auto-generated method stub
 //super.onEnabled(context);
 Toast.makeText(context, "onEnabled()", Toast.LENGTH_LONG).show();
}

@Override
public void onUpdate(Context context, AppWidgetManager appWidgetManager,
  int[] appWidgetIds) {
 // TODO Auto-generated method stub
 super.onUpdate(context, appWidgetManager, appWidgetIds);

 final int N = appWidgetIds.length;
      for (int i=0; i<N; i++) {
          int appWidgetId = appWidgetIds[i];
          updateAppWidget(context, appWidgetManager, appWidgetId);
        
          Toast.makeText(context, "onUpdate(): " + String.valueOf(i) + " : " +  String.valueOf(appWidgetId), Toast.LENGTH_LONG).show();
      }

}

public static void updateAppWidget(Context context, AppWidgetManager appWidgetManager,
  int appWidgetId){
 String currentTime = formatter.format(new Date());
 strWidgetText = currentTime;

 RemoteViews updateViews = new RemoteViews(context.getPackageName(), R.layout.hellowidget_layout);
 updateViews.setTextViewText(R.id.widgettext, "[" + String.valueOf(appWidgetId) + "]" + strWidgetText);
 appWidgetManager.updateAppWidget(appWidgetId, updateViews);

 Toast.makeText(context, "updateAppWidget(): " + String.valueOf(appWidgetId) + "\n" + strWidgetText, Toast.LENGTH_LONG).show();

}

static void SaveAlarmManager(AlarmManager tAlarmManager, PendingIntent tPendingIntent)
{
 myAlarmManager = tAlarmManager;
 myPendingIntent = tPendingIntent;
}

}

Download the files.