Edit an entry in a list view

Question

I'm working on a simple log app that lets the user enter a time and a note, and then displays the entered data in a ListView in a dedicated activity (MainActivty). The time and data are entered in a separate activity (AddTimeActivity) with two EditText's and are passed to MainActivity when tapping the save button through an adapter (TimeTrackerAdapter). Alternatively, a cancel button can be pressed when the user changes their mind. The AddTimeActivity can be accessed through an add button in the action bar default menu. Now I've added a delete button -which is working fine- and an edit button to each row in the list. Now The problem is: How can I add the editing feature without making a new activity dedicated to editing. In Other words, how can I make the AddTimeActivity work with editing and adding in the same time, how can I make my app know that the user tapped the add button and start the AddTimeActivity with empty EditText's, or the user tapped the edit button in one of the rows in the list and passes the the data to be edited to AddTimeActivity and displays them in the EditText's and saves the edited data in the same entry? Sorry for not showing any attempts but I'm actually clueless about the issue.

MainActivity.java

public class MainActivity extends AppCompatActivity {
    public TimeTrackerAdapter timeTrackerAdapter;
    public int TIME_ENTRY_REQUEST_CODE = 1;

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ListView listView = (ListView) findViewById(R.id.time_list);
        timeTrackerAdapter = new TimeTrackerAdapter();
        listView.setAdapter(timeTrackerAdapter);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        super.onCreateOptionsMenu(menu);
        MenuInflater menuInflater = getMenuInflater();
        menuInflater.inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (requestCode == TIME_ENTRY_REQUEST_CODE) {
            if (resultCode == RESULT_OK) {
                Bundle bundle = data.getExtras();
                String time = bundle.getString("time");
                String note = bundle.getString("note");
                TimeRecord timeRecord = new TimeRecord(time, note);
                timeTrackerAdapter.addTimeRecord(timeRecord);
                timeTrackerAdapter.notifyDataSetChanged();
            }
        }
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        // noinspection SimplifiableIfStatement
        if (id == R.id.add_time_item) {
            Intent intent = new Intent(getApplicationContext(), AddTimeActivity.class);
            startActivityForResult(intent, TIME_ENTRY_REQUEST_CODE);
            return true;
        }

        else if (id == R.id.about) {
            Intent aboutIntent = new Intent(getApplicationContext(), AboutScreen.class);
            startActivity(aboutIntent);
        }
        return super.onOptionsItemSelected(item);
    }
}

The AddTimeActivity, onSave and onCancel are the buttons' methods:

public class AddTimeActivity extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.add_time);
    }

    public void onCancel(View view) {
        finish();
    }

    public void onSave(View view) {
        Intent intent = new Intent(AddTimeActivity.this, MainActivity.class);
        EditText timeEditText = (EditText) findViewById(R.id.Time_Edit_Text);
        String time = timeEditText.getText().toString();
        EditText noteEditText = (EditText) findViewById(R.id.Note_Edit_Text);
        String note = noteEditText.getText().toString();
        intent.putExtra("time", time);
        intent.putExtra("note", note);
        this.setResult(RESULT_OK, intent);
        finish();
    }
}

TimeTrackerAdapter.java:

public class TimeTrackerAdapter extends BaseAdapter {
    public ArrayList<TimeRecord> times = new ArrayList<TimeRecord>();

    @Override
    public int getCount() {
        return times.size();
    }

    public TimeTrackerAdapter() {
        times.add(new TimeRecord("12:30", "this is the best"));
        times.add(new TimeRecord("2:30", "I need this"));
    }

    @Override
    public Object getItem(int position) {
        return times.get(position);
    }

    public void addTimeRecord(TimeRecord timeRecord) {
        times.add(timeRecord);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(final int position, View view, ViewGroup parent) {
        if (view == null) {
            LayoutInflater inflater = LayoutInflater.from(parent.getContext());
            view = inflater.inflate(R.layout.menu_layout, parent, false);
        }
        TextView timeView = (TextView) view.findViewById(R.id.time_textView);
        TextView noteView = (TextView) view.findViewById(R.id.note_TextView);
        Button deleteButton = (Button) view.findViewById(R.id.delete_entry);
        deleteButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                times.remove(position);
                notifyDataSetChanged();
            }
        });
        TimeRecord time = times.get(position);
        timeView.setText(time.getTime());
        noteView.setText(time.getNote());
        return view;
    }
}

Answer 1

The question is

How can I add the editing feature without making a new activity dedicated to editing.

or, more generally,

"how do I hand over information to the activity I'm calling ?"

You achieve this by adding extras to the intent which you use to start the activity. For example, in your 'MainActivity' before calling 'startActivityForResult()':

Intent intent = new Intent(this, MyOtherActivity.class);
// in your case, 'extraInformation' could be a boolean (add = yes|no)
intent.putExtra("MyExtraInformationKey", extraInformation);
startActivityForResult(intent,TIME_ENTRY_REQUEST_CODE);

Then in the 'onCreate()' method of the other activity, you question the intent for extras:

Intent i = getIntent();
if (i != null && i.hasExtra(getString("MyExtraInformationKey"))
{
    boolean myInfo = i.getBooleanExtra("MyExtraInformationKey");
    // proceed as appropriate...
}

For your case of buttons inside ListView rows, you could make the OnClickListener method call another method (like 'doCallMayOtherActivity()') in your 'MainActivity', handing over all relevant information (like the position in the 'times' ArrayList). This method would then start your add/edit activity, passing the old data out of 'times.get(position)' in a bundle as an extra to the intent.

To access the methods in 'MainActivity' from your adapter class, you could use the following code in 'getView()'

Button editButton=(Button) view.findViewById(R.id.edit_entry);
editButton.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {

         ((MainActivity)parent.getContext()).doCallMyOtherActivity(times.get(position));
    }

This way, your other activity could check for the existence of that bundle. If there is none, you have a case of 'add'. Else, you have a case of 'edit'.