Progressbar in Childview in ExpandableListview

Question

I'm trying to build an App.

What I want is an expandable List . Every element of an ArrayList<Object> should be also an element of the List. The Parenttitle should be the object's title. This object also contains an ArrayList<Double> with four elements.

Every Parent should have one child. The parent's child should display four ProgressBars. The first element of the ArrayList<Double> should set the progress of the first progressBar and so on.

This is what I have right now:

public class Lernen extends Activity {

private ExpandableListView mExpandableList;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_lernen);

    mExpandableList = (ExpandableListView) findViewById(R.id.expandable_list);

    ArrayList<Parent> arrayParents = new ArrayList<Parent>();
    ArrayList<String> arrayChildren = new ArrayList<String>();
    // MUSS GEÄNDERT WERDEN WENN DIE METHODE GETALLCARDS FERTIG IST!!!
    ArrayList<Karteikasten> kasten = new ArrayList<Karteikasten>();

    // teststub:
    Karteikasten foo = new Karteikasten("Kasten 1");
    Karteikasten bar = new Karteikasten("Kasten 2");
    kasten.add(bar);
    kasten.add(foo);
    System.out.println(kasten.size());
    try{
        // here we set the parents and the children
        for (int i = 0; i < kasten.size(); i++) {
            System.out.println("Durchlauf: " + i);
            System.out.println(kasten.get(0).getProgress().get(0).intValue());
            // for each "i" create a new Parent object to set the title and the
            // children
            Parent parent = new Parent();
            parent.setmTitle(kasten.get(i).getName());
            arrayChildren.add("Child " + i);
            parent.setmArrayChildren(arrayChildren);

            ProgressBar pb1 = (ProgressBar) findViewById(R.id.progressBar1);
            pb1.setProgress(kasten.get(i).getProgress().get(0).intValue());

            ProgressBar pb2 = (ProgressBar) findViewById(R.id.progressBar2);
            pb2.setProgress(kasten.get(i).getProgress().get(1).intValue());

            ProgressBar pb3 = (ProgressBar) findViewById(R.id.progressBar3);
            pb3.setProgress(kasten.get(i).getProgress().get(2).intValue());

            ProgressBar pb4 = (ProgressBar) findViewById(R.id.progressBar4);
            pb4.setProgress(kasten.get(i).getProgress().get(3).intValue());


            System.out.println("Kasten: " + kasten.get(i).getName());


            // in this array we add the Parent object. We will use the
            // arrayParents at the setAdapter
            arrayParents.add(parent);
        }
    } catch (Exception e){
        String stackTrace = Log.getStackTraceString(e);
        System.out.println("Fehlermeldung:");
        System.out.println(stackTrace);
    }

    // sets the adapter that provides data to the list.
    mExpandableList.setAdapter(new MyExpandableListAdapter(Lernen.this,
            arrayParents));

}
}

I get a NullPointerException at the line

pb1.setProgress(kasten.get(i).getProgress().get(0).intValue());

The problem could be, that the progressBar is in the layout list_item_child.xml , but this layout is not available for the activity.

Does anyone know how to fix it?

Thank you very much!

(And sorry for the bad language ;) )

Answer 1

You can set the items in each individual row by defining your own adapter (extend from BaseAdapter) and define all the styling parameters there. You can find a good tutorial on this topic here: http://techdroid.kbeanie.com/2009/07/custom-listview-for-android.html