Android ListView with Checkboxes: How to capture checked items?

Question

I have to do a ListView with CheckBoxes and then display the checked and unchecked items when user presses the button. The problem is I don't know how to do it, I manage to display the ListView with the CheckBox with this code:

package guestCheckBox.com;

import java.net.URL;
import java.util.ArrayList;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;

public class GuestCheckBox extends Activity {
    private ListView lView;             
    ArrayList<String> guest= new ArrayList <String>();

    @Override
    public void onCreate(Bundle icicle) {
    super.onCreate(icicle);
    setContentView(R.layout.main);  
    lView = (ListView) findViewById(R.id.ListView01);

    try{

        URL url = new URL(
        "http://tanjungrhu.jigsy.com/files/documents/Check.xml");
        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
        DocumentBuilder db = dbf.newDocumentBuilder();
        Document doc = db.parse(new InputSource(url.openStream()));
        doc.getDocumentElement().normalize();

        NodeList words = doc.getElementsByTagName("Guest");

        for(int i=0;i<words.getLength();i++){
            Node node = words.item(i);

            Element fstElmnt = (Element) node;
            NodeList NameList = fstElmnt.getElementsByTagName("Name");
            Element NameElement = (Element) NameList.item(0);
            NameList = NameElement.getChildNodes();
            guest.add((((Node) NameList.item(0)).getNodeValue()));
        }

}
catch (Throwable t){
    Toast.makeText(this, "Exeption:" + t.toString(), 2000).show();
}

//Set option as Multiple Choice. So that user can able to select more the one option from list
    lView.setAdapter(new ArrayAdapter<String>(this,
    android.R.layout.simple_list_item_multiple_choice, guest));
    lView.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);
    }
}

and here my main.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >

<TextView  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content"  />

<ListView 
    android:id="@+id/ListView01" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent">
</ListView>

</LinearLayout>

Would somebody show me how can I do a buttons and how will I show the checked and unchecked items when the user presses that buttons?

Answer 1

I didn't completely understand what the problem is but I can provide you one useful extension of ListView which helps you manipulate with string data (set\get checked values):

public class MultipleChoiceListView extends ListView {

public MultipleChoiceListView(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
}

public MultipleChoiceListView(Context context, AttributeSet attrs) {
    super(context, attrs);
}

public MultipleChoiceListView(Context context) {
    super(context);
}

@Override
public void setAdapter(ListAdapter adapter) {
    throw new RuntimeException(
        "This component doesn't support custom adapter. Use setData method to supply some data to show.");
}

/**
 * Sets the data that should be displayed for choosing
 * 
 * @param data List<String>
 */
public void setData(List<String> data) {
    super.setAdapter(new ArrayAdapter<String>(getContext(), android.R.layout.simple_list_item_multiple_choice, data));
    super.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);
}

/**
 * Sets the data that should be choosen by default
 * 
 * @param checkedData List<String>
 */
public void setCheckedData(List<String> checkedData) {
    for (int index = 0; index < getCount(); index++) {
        if (checkedData.contains(getItemAtPosition(index))) {
            setItemChecked(index, true);
        }
    }
}

/**
 * Returns checked by the user data passed in {@link #setData(List)}
 * 
 * @return List<String>
 */
public List<String> getCheckedData() {
    SparseBooleanArray checked = getCheckedItemPositions();
    List<String> checkedResult = new ArrayList<String>();

    for (int i = 0; i < checked.size(); i++) {
        if (checked.valueAt(i)) {
            checkedResult.add(getAdapter().getItem(checked.keyAt(i)).toString());
        }
    }
    return checkedResult;
}

}

Example of using:

    private void initListMultiple() {
    String[] data = new String[] {"first", "second", "third", "forth"};
    String[] checkedData = new String[] {"second", "forth"};

    multipleChoiceListView.setData(Arrays.asList(data));
    multipleChoiceListView.setCheckedData(Arrays.asList(checkedData));
}

private void onTestListButtonClicked(View view) {
    listResultTextView.setText(Arrays.toString(listView.getCheckedData().toArray()));
}