android listview项目背景图片

Question

我想从列表中更改单个项目的背景。我的代码将背景更改为所有项目。你能帮忙吗？这是代码：

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_height="wrap_content"
    android:layout_width="fill_parent"
    android:layout_marginRight="95dp"
    android:background="@drawable/friend_bubble"
    android:layout_below="@id/tv_message_date"
    >

<TextView
        android:id="@+id/tv_message_text"
        android:layout_height="wrap_content"
        android:layout_width="fill_parent"
        android:focusable="true"
        android:clickable="true"
        />

</RelativeLayout>

我的java代码是：

@Override
    public boolean onTouch(View view, MotionEvent event) {
        RelativeLayout rlBubble = (RelativeLayout)view.findViewById(R.id.tv_message_text).getParent();
        Drawable backgroundImage = rlBubble.getBackground();
        if (event.getAction() == MotionEvent.ACTION_DOWN) {
            if (backgroundImage == friendBubble ) {
                rlBubble.setBackgroundDrawable(friendBubbleSelected);
            } else {
                rlBubble.setBackgroundDrawable(userBubbleSelected);
            }
        } else if (event.getAction() == MotionEvent.ACTION_UP) {
            if (backgroundImage == friendBubbleSelected) {
                rlBubble.setBackgroundDrawable(friendBubble);
            } else {
                rlBubble.setBackgroundDrawable(userBubble);
            }
        }
        return false;
    }