如何从使用 getIntent() 接收数据的活动发送数据？

Question

I have an activity which uses an Adapter and RecyclerView to display a number of contacts to the user (activity A). The user can tap on a contact to view its info (activity B). They may then choose to edit that info; for this the user is taken to EditContact (activity C).

Is it possible to use startActivityForResult() in activity B to edit the database information in activity C and update the database and layout of activity B on RESULT_OK ?

EDIT Adding code snippets for clarity:

New/Edit Contact activity:

// Pass the data to the ViewContact activity
Intent addNewContact = new Intent();
addNewContact.putExtra(EXTRA_NAME, name);
addNewContact.putExtra(EXTRA_SURNAME, surname);
addNewContact.putExtra(EXTRA_COMPANY, company);
addNewContact.putExtra(EXTRA_PHONE_NUMBER, phoneNumbers);
addNewContact.putExtra(EXTRA_PHONE_TYPE, phoneTypes);
addNewContact.putExtra(EXTRA_EMAIL, emails);
addNewContact.putExtra(EXTRA_EMAIL_TYPE, emailTypes);
addNewContact.putExtra(EXTRA_ADDRESS, addresses);
addNewContact.putExtra(EXTRA_POSTCODE, postcode);
[...]

if (name.length() > 0 && phoneNumbers.length() > 0) {
    if (id != -1) {
        addNewContact.putExtra(EXTRA_ID, id);
    }
    setResult(RESULT_OK, addNewContact);
    onBackPressed(); // or finish()
} else {
    Toast.makeText(this, "Please enter at least a name and phone no.", 
    Toast.LENGTH_LONG).show();
}

ViewContact activity:

// On successful result, add the new contact & update the UI
    @Override
    public void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        if (requestCode == EDIT_CONTACT_REQUEST && resultCode == RESULT_OK) {

            int id = data.getIntExtra(EXTRA_ID, -1);
            // Check ID != -1 just in case, which shouldn't happen
            if (id == -1) {
                Toast.makeText(this, "Contact not updated", Toast.LENGTH_SHORT).show();
                return;
            }

            String name = data.getStringExtra(EXTRA_NAME);
            String surname = data.getStringExtra(EXTRA_SURNAME);
            String company = data.getStringExtra(AddNewContact.EXTRA_COMPANY);
            String phoneNumber = data.getStringExtra(AddNewContact.EXTRA_PHONE_NUMBER);
            String phoneType = data.getStringExtra(AddNewContact.EXTRA_PHONE_TYPE);
            String email = data.getStringExtra(AddNewContact.EXTRA_EMAIL);
            String emailType = data.getStringExtra(AddNewContact.EXTRA_EMAIL_TYPE);
            String address = data.getStringExtra(AddNewContact.EXTRA_ADDRESS);
            String postcode = data.getStringExtra(AddNewContact.EXTRA_POSTCODE);

            Contact contact =
                    new Contact(
                            name,
                            surname,
                            company,
                            phoneNumber,
                            phoneType,
                            email,
                            emailType,
                            address,
                            postcode);
            contact.setId(id);

            // TODO - this does not work, must use LiveData?
            // Update the database
            ContactRepository contactRepository = new ContactRepository(getApplication());
            contactRepository.update(contact);

            Toast.makeText(this, "Contact updated", Toast.LENGTH_SHORT).show();
        } else {
            Toast.makeText(this, "Contact not updated", Toast.LENGTH_SHORT).show();
        }

Answer 1

Yes it is possible. In Activity B, you can to start EditContact activity as follows:

Intent intent = new Intent(this, EditContact.class);
intent.putExtra(EditContact.EXTRA_CONTACT_ITEM, contactItem);
startActivityForResult(intent, EDIT_CONTACT_REQUEST_CODE);

When you're done editing the contact in EditContact activity, return RESULT_OK with edited contactItem and finish the activity:

Intent resultIntent = new Intent();
resultIntent.putExtra(EXTRA_CONTACT_ITEM, contactItem);
setResult(RESULT_OK, resultIntent);
finish();

Then, in Activity B, handle the results as follow:

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    if (requestCode == EDIT_CONTACT_REQUEST_CODE) {
            if(resultCode == Activity.RESULT_OK) {
                ContactItem contactItem= data.getParcelableExtra(EXTRA_CONTACT_ITEM);
                //Store item in database
            }
    }
}