Android – how to handle oncheckedchangelistener of radiogroup in a custom listview adapter

I am developing an application with a list view with a custom layout, as follows: it has four RadioButtons and a textview in the radiogroup. In fact, it will be displayed as a list of questions (textview) and answers (RadioButtons). The above view expands in my self-defined adapter, which extends arrayadapter < question >

The question is, how should I maintain the status of the RadioButton in the custom Adapter? When you press / select a RadioButton and scroll down the list, the adapter automatically recycles the view and the RadioButton status is lost

>So can anyone direct any links / information on this? > Or how should I implement the answer list?

Article 1 compliance: http://www.vogella.de/articles/AndroidListView/article.html

The link above uses Check@R_ 413_ 2419 @, in a similar way, I want to use radiogroup (RadioButtons) instead of Check@R_ 413_ 2419@es.

resolvent:

It's easy to adapt to the tutorial, so you can use radiogroup instead of Check@R_ 413_ 2419@. Bellow is an example (I used a radiogroup with four RadioButtons). First, you must modify the model class so that it can save new data:

public class Model {

    String question; // hold the question
    int current = NONE; // hold the answer picked by the user, initial is NONE(see below)
    public static final int NONE = 1000; // No answer selected
    public static final int ANSWER_ONE_SELECTED = 0; // first answer selected
    public static final int ANSWER_TWO_SELECTED = 1; // second answer selected
    public static final int ANSWER_THREE_SELECTED = 2; // third answer selected
    public static final int ANSWER_FOUR_SELECTED = 3; // forth answer selected

    public Model(String question) {
        this.question = question;  
    }

}

Then modify the getview () method to set the view according to the model:

@Override
        public View getView(int position, View convertView, ViewGroup parent) {
            View v = convertView;
            ViewHolder holder = null;

            if (v == null) {
                v = inflater.inflate(R.layout.the_row, parent, false);
                holder = new ViewHolder(v);
                v.setTag(holder);
                holder.group
                        .setOnCheckedchangelistener(new RadioGroup.OnCheckedchangelistener() {

                            public void onCheckedChanged(RadioGroup group,
                                    int checkedId) {
                                Integer pos = (Integer) group.getTag(); // To identify the Model object i get from the RadioGroup with getTag()
                                                                        //  an integer representing the actual position 
                                Model element = list.get(pos);          
                                switch (checkedId) { //set the Model to hold the answer the user picked
                                case R.id.answer0:
                                    element.current = Model.ANSWER_ONE_SELECTED;
                                    break;
                                case R.id.answer1:
                                    element.current = Model.ANSWER_TWO_SELECTED;
                                    break;
                                case R.id.answer2:
                                    element.current = Model.ANSWER_THREE_SELECTED;
                                    break;
                                case R.id.answer3:
                                    element.current = Model.ANSWER_FOUR_SELECTED;
                                    break;
                                default:
                                    element.current = Model.NONE; // Something was wrong set to the default
                                }

                            }
                        });
            } else {
                holder = (ViewHolder) v.getTag();
            }
            holder.group.setTag(new Integer(position)); // I passed the current position as a tag

            holder.t.setText(list.get(position).question); // Set the question body

            if (list.get(position).current != Model.NONE) {
                RadioButton r = (RadioButton) holder.group.getChildAt(list
                        .get(position).current);
                r.setChecked(true);
            } else {
                holder.group.clearCheck(); // This is required because although the Model Could have the current 
                                           // position to NONE you Could be dealing with a prevIoUs row where
                                           // the user already picked an answer. 

            }
            return v;
        }

Then comes the viewholder class:

class ViewHolder {
    TextView t = null;
    RadioGroup group;

    ViewHolder(View v) {
        t = (TextView) v.findViewById(R.id.textView1);
        group = (RadioGroup) v.findViewById(R.id.group_me);
    }

}

XML layout with radiogroup:

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

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <RadioGroup
        android:id="@+id/group_me"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal" >

        <RadioButton
            android:id="@+id/answer0"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:checked="false"
            android:text="Ans0" />

        <RadioButton
            android:id="@+id/answer1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:checked="false"
            android:text="Ans1" />

        <RadioButton
            android:id="@+id/answer2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:checked="false"
            android:text="Ans2" />

        <RadioButton
            android:id="@+id/answer3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:checked="false"
            android:text="Ans3" />
    </RadioGroup>

</LinearLayout>