Develop Reference

How to pass value from BroadcastReceiver to main activity

I want to tell my MainActivity, that it is starting automatically by BroadcastReceiver when boot is completed. It seems to be possible to send over putExtra some values to the MainActivity like this:
public class StartAppAtBootReceiver extends BroadcastReceiver {
private static final String key_bootUpStart = "bootUpStart";
private static boolean bootUpStart = true;
#Override
public void onReceive(Context context, Intent intent) {
if (Intent.ACTION_BOOT_COMPLETED.equals(intent.getAction())) {
Intent activityIntent = new Intent(context, MainActivity.class);
activityIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
activityIntent.putExtra(key_bootUpStart, bootUpStart);
context.startActivity(activityIntent);
}
}
}
But how can I receive that value inside my MainActivity?

On the BroadcastReceiver you send the intent to the Activity.
I modified your key to be public so that you can reuse it.
public static final String KEY_BOOTUP_START = "bootUpStart";
On the Activity you process the Intent.
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
processExtraData();
}
protected void onNewIntent(Intent intent)
{
super.onNewIntent(intent);
setIntent(intent);
processExtraData()
}
private void processExtraData()
{
Intent intent = getIntent();
// Use the data here.
boolean value = getIntent()
.getBooleanExtra(StartAppAtBootReceiver.KEY_BOOTUP_START, false);
}

In your activity you can get the intent which has started your activiy like:
in onCreateActivity:
Intent intent = getIntent();
Than:
Object value = intent.getExtra("key_bootUpStart");

Activity cant find Bundle in Intent

I am using an IntentService (for the first time), and I intend to return the result of this service by using a Bundle. However, when I do this, the main activity does not find the Bundle, returning null. What could cause this? The string keys match!
The code bellow outputs:
I/System.out: It's null
Main Activity:
public class MainMenu extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
//Some stuff here...
IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction(StorageHandler.TRANSACTION_DONE);
registerReceiver(broadcastReceiver, intentFilter);
Intent i = new Intent(this, StorageHandler.class);
startService(i);
}
private BroadcastReceiver broadcastReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
Bundle extra = getIntent().getBundleExtra("bundle");
if(extra == null){
System.out.println("It's null");
}
else {
ArrayList<String> objects = (ArrayList<String>) extra.getSerializable("objects");
System.out.println(objects.get(0));
}
}
};
}
IntentService:
public class StorageHandler extends IntentService{
public static final String TRANSACTION_DONE = "xx.xxxxx.xxxxxx.TRANSACTION_DONE";
public StorageHandler() {
super("StorageHandler");
}
public void onCreate(){
super.onCreate();
}
#Override
protected void onHandleIntent(Intent intent) {
notifyFinished();
}
private void notifyFinished(){
ArrayList<String> objects = new ArrayList<String>();
objects.add("Resulting Array here");
Bundle extra = new Bundle();
extra.putSerializable("objects", objects);
Intent i = new Intent();
i.setAction(xx.xxxxx.xxxxxx.StorageHandler.TRANSACTION_DONE);
i.putExtra("bundle", extra);
StorageHandler.this.sendBroadcast(i);
}

You're attempting to retrieve the data from the wrong Intent.
Change:
Bundle extra = getIntent().getBundleExtra("bundle");
To:
Bundle extra = intent.getBundleExtra("bundle");
The Intent that contains your data is supplied as one of the parameters of the BroadcastReceiver's onReceive() method.

you are using getIntent() to retrieve the broadcasted intent. This is wrong. The intent you have to use is the former paramter of onReceive. Change
Bundle extra = getIntent().getBundleExtra("bundle");
with
Bundle extra = intent.getBundleExtra("bundle");

Simply use this in your Activity:
In onResume callback you should register registerReceiver(broadcastReceiver, intentFilter);
And in onPause callback you should unregister this receiver. In your receiver use this:
Bundle extra = intent.getBundleExtra("bundle");
In your service use this code:
Intent i = new Intent(TRANSACTION_DONE).putExtra("bundle", extra);
this.sendBroadcast(i);
More information , see This Answer

Dont forget this in your onCreate MainActivity:
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//All your code here
}
I say this because I dont see that code line in your method!

call activity method from broadcast receiver

In the main activity, a layout is loaded that has some input fields and a submit button. When the submit button is clicked, the onClick handler method sends an sms back to the same mobile number :
SmsManager sms = SmsManager.getDefault();
sms.sendTextMessage(number, null, "hi", null, null);
There is a broadcast receiver defined that intercepts the message :
public class SmsReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
Bundle pdusBundle = intent.getExtras();
Object[] pdus=(Object[])pdusBundle.get("pdus");
SmsMessage messages=SmsMessage.createFromPdu((byte[]) pdus[0]);
if(messages.getMessageBody().contains("hi")){
abortBroadcast();
}
}
}
Now, from the broadcast receiver, I want to call a function(with parameter), which is within my main activity. Is that possible? If yes, what kind of code should i add in my broadcast receiver ?

Thanks #Manishika. To elaborate, making the Broadcastreceiver dynamic, instead of defining it in the manifest, did the trick. So in my broadcast receiver class, i add the code :
MainActivity main = null;
void setMainActivityHandler(MainActivity main){
this.main=main;
}
In the end of the onReceive function of the BroadcastReceiver class, I call the main activity's function :
main.verifyPhoneNumber("hi");
In the main activity, I dynamically define and register the broadcast receiver before sending the sms:
SmsReceiver BR_smsreceiver = null;
BR_smsreceiver = new SmsReceiver();
BR_smsreceiver.setMainActivityHandler(this);
IntentFilter fltr_smsreceived = new IntentFilter("android.provider.Telephony.SMS_RECEIVED");
registerReceiver(BR_smsreceiver,fltr_smsreceived);

Pass your Activity's context to BroadcastReceiver's contructor.
public class SmsReceiver extends BroadcastReceiver{
MainActivity ma; //a reference to activity's context
public SmsReceiver(MainActivity maContext){
ma=maContext;
}
#Override
public void onReceive(Context context, Intent intent) {
ma.brCallback("your string"); //calling activity method
}
}
and in your MainActivity
public class MainActivity extends AppCompatActivity {
...
public void onStart(){
...
SmsReceiver smsReceiver = new SmsReceiver(this); //passing context
LocalBroadcastManager.getInstance(this).registerReceiver(smsReceiver,null);
...
}
public void brCallback(String param){
Log.d("BroadcastReceiver",param);
}
}
hope it helps

use this
Intent intent=new Intent();
intent.setClassName("com.package.my", "bcd.class");
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(intent);

You can't directly call a function in your Activity unless it's a public static method but don't do so. I recommend this:
#Override
public void onReceive(Context context, Intent intent) {
Bundle bundle = new Bundle();
bundle.putExtraString("ACTION", "stopBroadcast");
// ### put what ever you need into the bundle here ###
Intent intent = new Intent();
intent.setClassName(context, "activity.class");
intent.putExtras(bundle);
context.startActivity(intent);
}
And then from your Activity's onCreate() get Bundle and take your actions as needed.

It's a little bit late, but nobody mentioned it.
There is no need for passing activity.
As #faizal specifies, IntentService is started from MainActivity, so, context in onReceive() is already instance of MainActivity.
It is enough to write smth like this:
#Override
public void onReceive(Context context, Intent intent) {
if(context instanceof MainActivity) {
MainActivity activity = (MainActivity) context;
}
}

sending intent extras from service to activity

I have a service that listens for (ON_BATTERY_CHANGE), then onReceive service sends a Broadcast to My MainActivity. The problem is that I somehow can't get them from service to my main activity. Code: Main Activity:
public class MainActivity extends Activity
private BroadcastReceiver batteryReceiverService;
private TextView text2;
....
protected void onCreate(Bundle savedInstanceState) {
text2=(TextView)findViewById(R.id.TV_text2);
batteryReceiverService = new BroadcastReceiver(){
#Override
public void onReceive(Context context, Intent intent) {
text2.setText("left: "+intent.getStringExtra("H")+" hours "+intent.getStringExtra("M")+" minute(s)");
Log.e("text2","text2 HHH " +intent.getStringExtra("H")); //log shows 0
Log.e("text2","text2 MMM " +intent.getStringExtra("H")); // log shows 0
}
};
registerReceiver(batteryReceiverService, new IntentFilter(UltimateBatterySaverService.BROADCAST_ACTION));
....
#Override
protected void onDestroy() {
unregisterReceiver(batteryReceiverService);
super.onDestroy();
}
Service:
public class UltimateBatterySaverService extends Service {
private Intent intent;
static final String BROADCAST_ACTION = "lt.whitegroup.ultimatebatterysaver";
private BroadcastReceiver batteryLevelReceiver;
....
public void onCreate() {
super.onCreate();
intent = new Intent(BROADCAST_ACTION);
}
#Override
public void onDestroy() {
unregisterReceiver(batteryLevelReceiver);
super.onDestroy();
}
IntentFilter batteryLevelFilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED);
batteryLevelReceiver = new BroadcastReceiver(){
#Override
public void onReceive(Context context, Intent intent){
// Receiving data, calculating and etc
averageChargingH=timeAllInHours;
averageChargingM=timeAllInMinutes;
// to put extras and send broadcast
does();
......
public void does(){
String strLong = Long.toString(averageChargingH);
String strLong2 = Long.toString(averageChargingM);
Log.e("cccccc","strLong h "+strLong); // getting good value not 0(everything ok)
Log.e("cccccc","strLong2 m"+strLong2); // getting good value not 0(everything ok)
intent.putExtra("H", strLong);
intent.putExtra("M", strLong2);
sendBroadcast(intent);
}
Any ideas why my information is not transfered correctly?

The does() method seems to be using variables in the same scope as onReceive so I'm guessing that the intent variable in does() is actually the Intent passed in from onReceive.
Try adding some logging before sending the broadcast to check if the action of the intent is correct, or simply create the broadcast intent in the onReceive method and name it intent2.

Is it possible to call putExtras() and getExtra() without starting a new activity?

I'm having two activities which are displayed side by side on one screen through a fragment for each activity. I want to send a String when I click a button on one of the activity, and then the other activity should retrieve the String I sent.
I know that it's possible to do that with the classic way setString() and getString() methods. But I'm wondering, could it be accomplished with putExtra() and getExtra() without opening the targeted activity on a new screen?

You can have both activity's intent as global variable and try using putExtra() from one activity and then getExtra() by another activity.
For Example,
public class activityOne extends Activity
{
public static Intent intent = null;
#Override
protected synchronized final void onCreate(final Bundle savedInstanceState)
{
intent = getIntent();
}
}
public class activityTwo extends Activity
{
public static Intent intent = null;
#Override
protected synchronized final void onCreate(final Bundle savedInstanceState)
{
intent = getIntent();
}
}
Now wherever you want you can access their intent like activityOne.intent,activityTwo.intent followed by null check

You can send the intent as a broadcast and have the receiving fragment register to that broadcast on its start (and unregister on its destroy).
Sending fragment:
Intent intent= new Intent(PARAM_TRANSFER);
intent.putExtra(key, extra);
sendBroadcast(intent);
Receiving fragment:
register:
IntentFilter intentFilter = new IntentFilter(PARAM_TRANSFER);
registerReceiver(mReceiver, intentFilter);
unregister:
try {
unregisterReceiver(mReceiver);
} catch (Exception e) {}
getting the param:
private class MyReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
intent.getExtra(key);
}
}