Switching between activities without losing data-CodePudding

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?

CodePudding user response：

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";

CodePudding user response：

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;

CodePudding user response：

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?