send data from activity to another without start it

Question

If I have two activities Activity1 and Activity2 and I want to send data from Activity1 to Activity2 without Start Activity2

I know if I want to start Activity2 I use this code in Activity1.java

Intent intent ;
Bundle bundle = new Bundle();

bundle.putString(BG_SELECT, hexColor);

intent = new Intent(getApplicationContext(), Activity2.class);

intent.putExtras(bundle);

// this is to start but I want just refresh Activity2 not start it
startActivityForResult(intent, uniqueNo);

and in Activity2.java

bundle = getIntent().getExtras();

if (bundle != null) {
   bgColor = bundle.getString(SebhaActivity.BG_SELECT);
   System.out.println("in Activity2, selected BG: "+bgColor);

}

How to refresh Activity2 to find data in it without Start it? Thanks in Advance.

Answer 1

if the next activity (where you need data, Activity2 i.e) wont start from here you can save the data in SharedPreferences in Activity 1 and access it in activity2 when you get there

Answer 2

You can use the LocalBroadcastManager. For your scenario, i.e., Activity1 sends something to Activity2, you would do something like the following.

# Activity1

Intent intent = new Intent("INTENT_NAME").putExtra(BG_SELECT, hexColor);
LocalBroadcastManager.getInstance(Activity1.this).sendBroadcast(intent);

On Activity2, you would need first to register the receiver, for instance, on its onCreate method, then get the intent using a BroadcastReceiver as following

# Activity2

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    LocalBroadcastManager.getInstance(this).registerReceiver(mReceiver, new IntentFilter("INTENT_NAME"));
}

Then, register the mReceiver to retrieve the BG_SELECT field

# Activity2

private BroadcastReceiver mReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        String receivedHexColor = intent.getStringExtra(BG_SELECT);
    }
};

Answer 3

I think here SharedPreferences is become unbeatable.

SharedPreferences is application specific, i.e. the data is lost on performing one of the following options: PREFS_NAME is the name of the file. mode is the operating mode. editor.commit() is used in order to save changes to shared preferences

Your Code goes like this

In First Activity From where you share data

  SharedPreferences preferences=getSharedPreferences("PhoneBook",MODE_PRIVATE);
    SharedPreferences.Editor editor=preferences.edit();

    editor.putInt("registration_id",c.getInt(c.getColumnIndex("db_regiser_id")));
    editor.putBoolean("IsLogin",true);
    editor.commit();

In Second Activity get data like this

SharedPreferences preferences=getSharedPreferences("PhoneBook",MODE_PRIVATE);
 int registration_id = preferences.getInt("registration_id", 0);

Use of SharedPreferences is quite safe.

Also visit

https://developer.android.com/training/data-storage/shared-preferences.html

Hope this one will be helpful.