Я пытаюсь установить цвет фона для элемента, когда пользователь нажимает на дочерний элемент в моемexpandableListView.

Вот код:

expListView.setOnChildClickListener(new OnChildClickListener() {

@Override
        public boolean onChildClick(ExpandableListView parent, View v, final int groupPosition, final int childPosition, long id) {

            AlertDialog.Builder builder = new AlertDialog.Builder(New_annonce_act_step2.this);
            builder.setMessage("Vous avez choisi la catégorie " +listDataChild.get(listDataHeader.get(groupPosition)).get(childPosition) +", Continuer ?")
            .setPositiveButton("Oui", new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int id) {
                    Intent myIntent = new Intent(New_annonce_act_step2.this, New_annonce_act_step22.class);
                    myIntent.putExtra("titre", titre);
                    myIntent.putExtra("categorie", categorie);
                    New_annonce_act_step2.this.startActivity(myIntent);
                    finish();

                    overridePendingTransition(R.anim.left_to_right, R.anim.right_to_left);

                }
            })
            .setNegativeButton("Non", new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int id) {
                    // User cancelled the dialog
                }
            });
            // Create the AlertDialog object and return it
            builder.create();
            builder.show();

            return false;
        }

    });

Вот объявление ExpandableListView в макете:

 <ExpandableListView
            android:id="@+id/nouvelle_annonce_categorie"
            android:layout_width="match_parent"
            android:layout_height="320dp"
            android:layout_marginLeft="1dp"
            android:layout_marginRight="1dp"
            android:choiceMode = "singleChoice"
            android:listSelector = "@drawable/selector_categorie_item"
            android:layout_marginTop="15dp" />

А вот коэффициент selector_categorie_item.xml:

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android"
    android:exitFadeDuration="@android:integer/config_mediumAnimTime">

    <item android:drawable="@android:color/holo_blue_bright" android:state_pressed="true"/>
    <item android:drawable="@android:color/holo_blue_light" android:state_selected="true"/>
    <item android:drawable="@android:color/holo_blue_dark" android:state_activated="true"/>

</selector>