如何将第一个Activity中的数据保存到第二个Activity中？

Question

I am writing an app for a restaurant and would like to be able to select a specific dish that you would like to order and that it has been added to OrderActivity where, in the form of ListView, you will be displaying individual dishes selected by the user.
I do not know how to do it in the best way, do you need to use the interface and maybe just get the intention of a specific dish?
And how do I save a specific request in OrderActivity so that when I return to an earlier Activity I do not lose the saved data in the ListView?

I managed to solve the problem of transmitting data from one Activity to the second Activity and showing it on the ListView, I do not know how to save that data, say on the example of SharedPreferences?
If I click the back button in my second Activity, my list becomes empty.
I understand that the fault is on onResume() because I am killing the second Activity, when I come back to the first, is that so?

How to solve the problem?

FirstActivity:

public class DinnerDetailActivity extends AppCompatActivity {

    public static final String EXTRA_DINNER = "dinner"; 

    private final int requestCode = 1;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_obiady_domowe_detail);


        int dinner = (Integer) getIntent().getExtras().get(EXTRA_DINNER);

        String dinnerName = Dinner.dinn[dinner].getName();
        TextView textView = (TextView) findViewById(R.id.dinner_text);
        textView.setText(dinnerName);


        int dinnerImage = Dinner.dinn[dinner].getImageResourceId();
        ImageView imageView = (ImageView) findViewById(R.id.dinner_image);
        imageView.setImageDrawable(getResources().getDrawable(dinnerImage));
        imageView.setContentDescription(dinnerName);



        Toolbar myChildToolbar = (Toolbar) 
        findViewById(R.id.my_child_toolbar_obiady_detail);
        setSupportActionBar(myChildToolbar);

        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    }

   /* @Override
    protected void onResume() {

        SharedPreferences sharedPref = getSharedPreferences("KEY", Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = sharedPref.edit();
        editor.putString("KEY", listItems.add();
        editor.apply();

        Toast.makeText(getApplicationContext(), "Save!", Toast.LENGTH_SHORT).show();
        super.onResume();
    }
*/

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {

        getMenuInflater().inflate(R.menu.menu_main, menu);

        TextView textView = (TextView) findViewById(R.id.dinner_text);
        CharSequence dinnerName = textView.getText();
        MenuItem menuItem = menu.findItem(R.id.action_share);
        ShareActionProvider shareActionProvider = (ShareActionProvider) MenuItemCompat.getActionProvider(menuItem);
        Intent intent = new Intent(Intent.ACTION_SEND);
        intent.setType("text/plain");
        intent.putExtra(Intent.EXTRA_TEXT, dinnerName);
        shareActionProvider.setShareIntent(intent);

        return true;
    }


    @Override
    public boolean onOptionsItemSelected(MenuItem item) {

        switch (item.getItemId()) {
            case R.id.action_create_order:
                Intent intent = new Intent(this, TopFragment.class);
                startActivity(intent);
                return true;
            default:

        return super.onOptionsItemSelected(item);
     }
    }

//Click button, and add dinnerName to SecondActivity ListView

    public void addInOrder(View view) { 

    int dinner = (Integer) getIntent().getExtras().get(EXTRA_DINNER); 

    String dinnerName = Dinner.dinn[dinner].getName();

    Intent intent1 = new Intent(this, CreateYourOrderActivity.class);
    intent1.putExtra("OK", dinnerName);
    startActivityForResult(intent1, requestCode);


    }
}

Second Activity:

public class CreateYourOrderActivity extends AppCompatActivity {

    private ListView listView;
    private ArrayAdapter<String> adapter;
    private ArrayList<String> listItems;

    private String dinner;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_zloz_zamowienie);

        Toolbar myChildToolbar = (Toolbar) 
            findViewById(R.id.my_child_toolbar);

        setSupportActionBar(myChildToolbar);

        ActionBar ab = getSupportActionBar();
        ab.setDisplayHomeAsUpEnabled(true);

        textView = (TextView) findViewById(R.id.text_view);

    }
/*
    @Override
    protected void onResume() {

        SharedPreferences sharedPref = getSharedPreferences("KEY", Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = sharedPref.edit();
        editor.putString("KEY", obiad);
        editor.apply();

        listItems.add(obiad);
        adapter.notifyDataSetChanged();

        Toast.makeText(getApplicationContext(), "Save!", Toast.LENGTH_SHORT).show();
        super.onResume();
    }
*/
    /* @Override
    public void onBackPressed() {
        SharedPreferences sharedPref = getSharedPreferences("KEY", Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = sharedPref.edit();
        editor.putString("KEY", listItems.get(0).toString());
        editor.apply();

        Toast.makeText(getApplicationContext(), "Save!", Toast.LENGTH_SHORT).show();
    }*/

    public void saveInfo(View view) {



    }

    public void openInfo(View view) {

        SharedPreferences sharedPref = getSharedPreferences("KEY", Context.MODE_PRIVATE);
        String obiadNames = sharedPref.getString("KEY", "");

        textView.setText(obiadNames);
        //listItems.add(obiadNames);
        //adapter.notifyDataSetChanged();

    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {

        getMenuInflater().inflate(R.menu.menu_main, menu);

        return true;
    }


    @Override
    public boolean onOptionsItemSelected(MenuItem item) {

        switch (item.getItemId()) {
            case R.id.action_create_order:
                Intent intent = new Intent(this, MainActivity.class);

                return true;
            default:

                return super.onOptionsItemSelected(item);
        }

    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {


       Intent intent = getIntent();

        if(resultCode == RESULT_OK) {
           if(requestCode == 1){


            dinner = data.getExtras().getString("OK");

            listView = (ListView) findViewById(R.id.listView);


            listItems.add(dinner);


            adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, listItems);
            listView.setAdapter(adapter);

            //  adapter.add(dinner);
            adapter.notifyDataSetChanged();

            finish();
        }

       }
    }

So as you can see in the attached photos we have the first Activity, several dishes from which we go to the detailed Activity, where we have AddOrder Button.
I would like to click on this button to add the name of my specific dish in the 3 Activities that you see in the pictures.
This is to be added as a ListView.
Also, I would like to have the names of dishes not gone when I return to 1 Activity.

Answer 1

SharedPreferences are for simple values.

You'll need a proper database (Sqlite, Realm, or other) with which you can persistently store and query your data across the entire application without passing entire objects across Intent boundaries.

More specifically, you need to replace the Dinner.dinn array

To get specific items when you go to a detail view, you can pass the database ID of the object, then query it later.

When you add a new item and go back to the list, you will update the adapter with all the database entries