How do I pass variables between activities in Android?

Question

Assume I have a "post submission" feature on my application. There are two activities and layouts:

Main post activity
Location selection activity

How can I pass variables between them when they're already opened? I already know how when they haven't been opened. I use "singleTask" mode to prevent multiple instances.

Reason I need this is because there's a button that links to LocationSelectionActivity on the MainPostActivity. I want when someone clicked the button, select the location, then go back to the MainPostActivity without any activity restart so the filled fields will not reset.

you can just put your informations as extra inside the Intent you use to start the second activity — Gregorio Palamà, Sep 21 '18 at 13:22
Follow this: https://stackoverflow.com/questions/10407159/how-to-manage-startactivityforresult-on-android — aminography, Sep 21 '18 at 13:29

score 0 · Answer 1 · answered Sep 21 '18 at 13:24

0

Use onActivityResult() with startActivityForResult().

Reference: https://developer.android.com/training/basics/intents/result

answered Sep 21 '18 at 13:24

Gokul Nath KP

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score 0 · Answer 2 · answered Sep 21 '18 at 13:31

You're probably looking for onNewIntent, you can override it in your Activity class and retrieve the new Intent in your onResume method.

    /**
     * Override super.onNewIntent() so that calls to getIntent() will return the
     * latest intent that was used to start this Activity rather than the first
     * intent.
     */
    @Override
    public void onNewIntent(Intent intent){
        super.onNewIntent(intent); // Propagate.
        setIntent(intent); // Passing the new intent to setIntent() means this new intent will be the one returned whenever getIntent() is called.
    }

score 0 · Answer 3 · answered Sep 21 '18 at 13:44

You should not use Activities for this, you are in your own "main process" so you should be using 1 Activity and 2 Fragments for this.

Then you can use locationSelectionFragment.setTargetFragment(this); in MainPostFragment before it is added to Activity's fragment transaction, this lets you use getTargetFragment() to just pass back the value:

((MainPostFragment)getTargetFragment()).giveValueBack(value);

But there are multiple other options each with their own strengths and weaknesses as described in this article.

How do I pass variables between activities in Android?

3 Answers3