Switching between activities without losing data

Question

I keep losing data when pressing the back button after going back from activity 2 to 1.

when passing the data to activity 2 I'm using

   intent = new Intent(getApplicationContext(), secondactivity.class);
   startActivity(intent);

to launch the second activity. is it possible not to lose the data without using sharedpreference when pressing the back button?

Answer 1

You can store your data in the Application class and use it everywhere

Create a class:

public class MyCustomApplication extends Application {
   String myData = "";
}

in manifest add class name as android:name

<application 
   android:name=".MyCustomApplication"
   android:icon="@drawable/icon" 
   android:label="@string/app_name" 
...>

access it like this from any activity

 String myData = ((MyCustomApplication)getApplication()).myData; 
((MyCustomApplication)getApplication()).myData = "new value";

Answer 2

Create a new class

public class myClass{
    public static String myData;
}

In your activity

myClass.myData = "Set a text";

Then call it everywhere in you activity

String myData = myClass.myData;

Answer 3

When launching your second activity, you can specify that you are expecting a result from the activity:

int LAUNCH_SECOND_ACTIVITY = 1
Intent i = new Intent(this, SecondActivity.class);
startActivityForResult(i, LAUNCH_SECOND_ACTIVITY);

Then, in your second activity, you can override the onBackPressed()

@Override
public void onBackPressed() {
    Intent data = new Intent();
    // add data to Intent 
    setResult(Activity.RESULT_OK, data);
   super.onBackPressed(); }

Possible duplicate of How do I pass data between activities when I press back button in Android?