Question

What I have: I have a ListView with custom rows, having a CheckBox & two TextViews in each row. I have a button for “Select All”.

What i want: I want that when I click the button, all the CheckBox in ListView get checked/unchecked.

What is the problem: In OnClick of the “Select All” button. i am doing this:

public void OnClickSelectAllButton(View view)
{
    ListView l = getListView();
    int count = l.getCount();
    for(int i=0; i<count; ++i) 
    {
       ViewGroup row = (ViewGroup)l.getChildAt(i);
       CheckBox check = (CheckBox) row.findViewById(R.id.checkBoxID);
       check.setChecked(true); // true for select all and false for unselect all etc..
    }
}

Here l.getChildAt(i) is giving me the visible items only. And when the index goes out of visible items, the problem occurs. I want to check all the CheckBox in List, not just the visible ones.

Answer 1

It will occur, because ListView adapter reuses views. The way you are trying to do is incorrect. I don’t think you ever should access listview rows through listview children.

Introduce a variable in your activity, that will hold the current state (boolean checkAll). When the user presses the button, it must set “checkAll” to true, and call notifyDataSetChanged() (for arrayadapter), or requery() (for cursoradapter) on your ListView’s adapter. In adapter’s getView() method introduce a check for this flag, so if (checkAll) {check the check box}