How to modify the value in an ArrayList<HashMap<String, String>>?

Question

I have got in trouble about how to modify the value in an ArrayList< HashMap< String, String>>.

For example, I have a ArrayList

1 one

2 two

3 three

and now I would like to edit 1 one to 0 zero then the list will as

0 zero

2 two

3 three

how do I do that?

sorry, i forgot to post my code

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    getLayoutInflater().inflate(R.layout.budgetcounting, contentFrame);


    setTitle(drawer_menu[3]);
    listView = (ListView)findViewById(R.id.bc_listItems);

    list = new ArrayList<HashMap<String, String>>();

    balance = (TextView)findViewById(R.id.bc_balance);
    budget = (TextView)findViewById(R.id.bc_budget);
    balance.setText("Balance: ");
    budget.setText("Budget: ");

    addBtn = (Button)findViewById(R.id.bc_btnadd);
    budgetBtn = (Button)findViewById(R.id.bc_btnbudget);

    addBtn.setOnClickListener(this);
    budgetBtn.setOnClickListener(this);

    HashMap<String, String> temp = new HashMap<String, String>();
    temp.put(FIRST_COLUMN, "1");
    temp.put(SECOND_COLUMN, "one");

    HashMap<String, String> temp1 = new HashMap<String, String>();
    temp1.put(FIRST_COLUMN, "2");
    temp1.put(SECOND_COLUMN, "two");

    HashMap<String, String> temp2 = new HashMap<String, String>();
    temp2.put(FIRST_COLUMN, "3");
    temp2.put(SECOND_COLUMN, "three");

    list.add(temp);
    list.add(temp1);
    list.add(temp2);

    adapter = new BC_ListViewAdapter(this, list);
    listView.setAdapter(adapter);

    registerForContextMenu(listView);
}

Here's the code for the delete part:

@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
    super.onCreateContextMenu(menu, v, menuInfo);
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.bc_contextmenu, menu);
}

@Override
public boolean onContextItemSelected(MenuItem item) {
    final AdapterView.AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo)item.getMenuInfo();
    switch (item.getItemId()) {
        case R.id.bc_contextmenu_delete:
            list.remove(info.position);
            adapter.notifyDataSetChanged();
            return true;
        default:
            return super.onContextItemSelected(item);
    }
}

Adapter:

public class BC_ListViewAdapter extends BaseAdapter {

public ArrayList<HashMap<String, String>> list;
Activity activity;

TextView txtFirst;
TextView txtSecond;

public BC_ListViewAdapter(Activity activity, ArrayList<HashMap<String, String>> list) {
    super();
    this.activity = activity;
    this.list = list;
}

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

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

@Override
public long getItemId(int position) {
    return 0;
}


@Override
public View getView(int position, View convertView, ViewGroup parent) {

    LayoutInflater inflater = activity.getLayoutInflater();

    if (convertView == null) {
        convertView = inflater.inflate(R.layout.bc_column, null);

        txtFirst = (TextView) convertView.findViewById(R.id.bc_itemname);
        txtSecond = (TextView) convertView.findViewById(R.id.bc_itemvalue);
    }
        HashMap<String, String> map = list.get(position);
        txtFirst.setText(map.get(FIRST_COLUMN));
        txtSecond.setText(map.get(SECOND_COLUMN));

        return convertView;
}
}

Is that a list with three maps (one entry each) or a list with one map (three entries)? — Thilo
– Thilo, Commented Jan 23, 2016 at 13:11
sorry, i forgot to post my code. Here I am trying to edit those value. I wish to do a counter in the future. That is I have 10 dollar. I add a sweet which cost 8 dollar into the list. That the application would shows I have 2 dollars left. But I need to edit the value in case I type in the wrong value. Thanks a lot! — rascee
– rascee, Commented Jan 23, 2016 at 13:21

Msp · Accepted Answer · 2016-01-23 14:06:21Z

1

Is that what you need?

list.get(0).put(FIRST_COLUMN, "0");
list.get(0).put(SECOND_COLUMN, "zero");

EDIT:

Change this in your adapter,

@Override
public long getItemId(int position) {
    return position;  //instead of zero
}

And use list.remove(info.id) to remove item from list

edited Jan 23, 2016 at 14:06

answered Jan 23, 2016 at 13:24

Msp

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7 Comments

rascee Over a year ago

Is it really need to remove and add? I can't directly edit these values? anyway, Thank You! But I have a question. Once I remove the 1 one, position[0] in the list would become empty. I wonder that if 2 two (position[1]) would change position[0]?

rascee Over a year ago

Thank you! Last question. I would use context menu to do the remove and edit part. Once I use list.remove(info.position); it will always remove the last item that is 3 three from the list no matter which item I choose to delete.

Msp Over a year ago

Use list.remove(info.id); instead of list.remove(info.position)

rascee Over a year ago

It does't work. It has't change anythings. I wonder if it related to the HashMap in the ArrayList. I also post the adapter. Would you mind to have a look. It may has something wrong to cause my problem.

rascee Over a year ago

it does't works anyway. I have tried to use list.remove(1) instead of list.remove(info.position) in order to remove 1 one. But it still remove the last item.

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