Passing values from Activity2 to Activity1 without visiting Activity1

Question

I have a loginActivity and a MainActivity

I have used SharedPreferences to store some values in some variables in the loginActivity. Now I want to use these values(They're boolean values) in MainActivity without re=opening MainActivity. How do I do this?

Also, the SharedPreferences are in an onClick method for a button . Thank you!

When opening mainactivity via intent, just set your values into intent like intent.putExtra("key",{boolean_value}) — Gautam, Mar 22 '18 at 19:01
You are going to get higher quality answers if you show a [mcve] — , Mar 22 '18 at 19:10
You don't need to open an activity to read from SharedPreferences. Can you add some code with an [edit]? — OneCricketeer, Mar 22 '18 at 19:19
since value is stored is SharedPrefs you can access it any activity. Just before your activity renders just grab that data. — Shubham Agarwal Bhewanewala, Mar 22 '18 at 19:22

score 0 · Answer 1 · answered Mar 22 '18 at 19:06

0

I'm assuming that MainActivity starts first, and loginActivity is on top of it in the stack. When loginActivity finishes, you can read the SharedPreferences in MainActivity#onResume.

If you mean that you want to do things in MainActivity while it's in the background or backstack, don't. An activity that is not in the foreground should not be doing any work, and in fact cannot be counted on to exist at all.

answered Mar 22 '18 at 19:06

StackOverthrow

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See e.g. here for an example https://stackoverflow.com/a/2091482/1615430 – RookieGuy Mar 22 '18 at 19:12
@RookieGuy That doesn't address the question. – StackOverthrow Mar 22 '18 at 19:24
having read it again, I agree with you.. at least it shows an example how to use the extras from the intent in onResume which is the common way to do inter-activity-communication – RookieGuy Mar 22 '18 at 19:28

score 0 · Answer 2 · answered Mar 22 '18 at 19:14

There are two ways

1.If you have set the values in shared preferences you can access them from any activity with relevant permissions.

2.Pass when moving from one to another activity and close the other one if need.

        Intent toMain = new Intent(LoginActivity.this, MainActivity.class);
        toMain.putExtra("bool1", "true"); //Optional parameters
        LoginActivity.this.startActivity(toMain);
        //To prevent go back to login
        finish();

then from onCreate of mainActivity

Bundle fromLogin = getIntent().getExtras();
if (extras != null) {
    String value = extras.getString("bool1");
    //convert this to boolean
}

Passing values from Activity2 to Activity1 without visiting Activity1

2 Answers2