POC of saving to files

MainActivity.java

public class MainActivity extends AppCompatActivity {

    private Button button;

    ActivityResultLauncher<Intent> launcher = registerForActivityResult(
            new ActivityResultContracts.StartActivityForResult(),
            new ActivityResultCallback<ActivityResult>() {
                @Override
                public void onActivityResult(ActivityResult result) {
                    Uri uri = result.getData().getData();

                    try {
                        OutputStream stream = getContentResolver().openOutputStream(uri);
                        PrintWriter writer = new PrintWriter(stream);

                        writer.println("Hello World");
                        writer.println(55);
                        writer.println("some more text");
                        writer.close();

                        Toast.makeText(MainActivity.this, "Finished", Toast.LENGTH_LONG).show();
                    } catch (FileNotFoundException e) {
                        throw new RuntimeException(e);
                    }
                }
            }
    );

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

        button = findViewById(R.id.button);

        button.setOnClickListener(v -> {
            createFile();
        });
    }

    private void createFile() {
        Intent intent = new Intent(Intent.ACTION_CREATE_DOCUMENT);
        intent.addCategory(Intent.CATEGORY_OPENABLE);
        intent.setType("application/text");
        intent.putExtra(Intent.EXTRA_TITLE, "file.txt");

        launcher.launch(intent);
    }


}