Question

I have an Android activity with a list. Each item can be clicked and when that happens a new layout is displayed below the text with some buttons.

I wanted to set the selected item to the center when clicked, because when the last one is clicked the menu is lost and you need to scroll, which is very confusing.

My code saves the position of the last selected item, so when another one is clicked, it can hide the edit menu for that item.

When I use setSelection this behavior breaks, it seems like the positions in the listView changes, because that logic doesn’t work anymore. All options remain visible, different rows are reacting instead of the one clicked, and if I click a row below the selected one, it throws a NullPointerException.

I’ve tried to do this in many different ways, storing the view instead of the position, using scrollTo instead of setSelection, etc… but it always seems to break. This is the code in question, do you guys have any ideas? Thanks a lot.

mListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {

  @Override
  public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
    RelativeLayout itemView = (RelativeLayout) mListView.getChildAt(position);
    LinearLayout showItemOptionsView = (LinearLayout) itemView.findViewById(R.id.itemOptionsView);
    showItemOptionsView.setVisibility(View.VISIBLE);

    // Sets previous to GONE
    if (mPreviouslySelectedItemPosition != -1) {
      itemView = (RelativeLayout) mListView.getChildAt(mPreviouslySelectedItemPosition);
      showItemOptionsView = (LinearLayout) itemView.findViewById(R.id.itemOptionsView);
      showItemOptionsView.setVisibility(View.GONE);
    }

    mListView.setSelection(position);

    mPreviouslySelectedItemPosition = position;
  }

this is the layout

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >

    <TextView
    android:id="@+id/groceryListName"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center"
    android:textSize="20dp" />

    <LinearLayout
    android:id="@+id/addItemView"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_below="@id/groceryListName"
    android:gravity="center_vertical"
    android:orientation="horizontal" >

    <EditText
        android:id="@+id/itemName"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:inputType="textAutoComplete" />

    <Button
        android:id="@+id/addItem"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:gravity="right|center_vertical"
        android:onClick="addItem"
        android:text="@string/addItem" />
</LinearLayout>

<TextView
    android:id="@+id/clickOnItemToEdit"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_below="@id/addItemView"
    android:layout_marginBottom="5dp"
    android:text="@string/clickOnItemToEdit"
    android:textSize="10dp" />

<Button
    android:id="@+id/shop"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_gravity="bottom"
    android:onClick="startShoppingActivity"
    android:text="@string/startShopping" />

<ListView
    android:id="@+id/items"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:layout_above="@id/shop"
    android:layout_below="@id/clickOnItemToEdit" />

</RelativeLayout>

and this is the row’s layout

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/showItemView"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">

    <TextView
        android:id="@+id/itemId"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:visibility="gone" />

    <TableRow
        android:id="@+id/itemTable"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:gravity="center_vertical"
        android:stretchColumns="3" >

        <Button
            android:id="@+id/itemQuantityLess"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="right|center_vertical"
            android:focusable="false"
            android:focusableInTouchMode="false"
            android:onClick="lessQuantityHandler"
            android:text="@string/itemQuantityLess" />

        <TextView
            android:id="@+id/itemQuantity"
            android:layout_width="40dp"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:gravity="center_horizontal"
            android:textSize="20sp" />

        <Button
            android:id="@+id/itemQuantityMore"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="left|center_vertical"
            android:focusable="false"
            android:focusableInTouchMode="false"
            android:onClick="moreQuantityHandler"
            android:text="@string/itemQuantityMore" />

        <TextView
            android:id="@+id/itemProductName"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="left|center_vertical"
            android:textSize="20sp" />
    </TableRow>

    <LinearLayout
        android:id="@+id/itemOptionsView"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_alignParentLeft="true"
        android:layout_below="@id/itemTable"
        android:gravity="center|right"
        android:orientation="horizontal"
        android:visibility="gone" >

        <Button
            android:id="@+id/editItem"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:gravity="right|center_vertical"
            android:onClick="editItem"
            android:text="@string/editItem" />

        <Button
            android:id="@+id/removeItem"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:gravity="right|center_vertical"
            android:onClick="removeItem"
            android:text="@string/removeItem" />
    </LinearLayout>

</RelativeLayout>

This is the code from the adapter

  @Override
  public void bindView(View view, Context context, Cursor cursor) {
    int idIndex = cursor.getColumnIndexOrThrow(ItemAndroidDAO._ID);
    String id = cursor.getString(idIndex);
    TextView idView = (TextView) view.findViewById(R.id.itemId);
    idView.setText(id);

    int productIdIndex = cursor.getColumnIndexOrThrow(ItemAndroidDAO.PRODUCT_ID_COLUMN);
    String productId = cursor.getString(productIdIndex);

    Product product = productFacade.findById(Long.parseLong(productId));
    // The product must exist, otherwise it fails.
    AppException.assertNotNull(product, "The related product cannot be null.");

    TextView productIdView = (TextView) view.findViewById(R.id.itemProductName);
    productIdView.setText(product.getName());

    int quantityViewIndex = cursor.getColumnIndex(ItemAndroidDAO.QUANTITY_COLUMN);
    int quantity = cursor.getInt(quantityViewIndex);
    TextView quantityView = (TextView) view.findViewById(R.id.itemQuantity);
    quantityView.setText(Integer.toString(quantity));
  }

and the newView() (it's in a superclass)

      @Override
      public View newView(Context context, Cursor cursor, ViewGroup parent) {
        LayoutInflater layoutInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View listView = (View) layoutInflater.inflate(getLayoutResource(), null);
        bindView(listView, context, cursor);
        return listView;
      }

API Level is 7 (2.1).

Answer 1

I don’t know if I understood what’s happening with your code(or what you are trying to do) but you could try another approach. Instead of trying to work with your selected row in the onItemClick() method make your adapter have a field:

long selectedPosition = -1; // -1 no visible LinearLayout

then in the onItemClick() will simply have:

@Override
protected void onListItemClick(ListView l, View v, int position, long id) {  
        // setter method that will update the adapter's selectedPosition to hold the id of the row clicked
    adapter.setSelectedPosition(id); 
        // notify the adapter that it need to update the data
        // I don't know exactly what adapter you implement, the notifiyDataSetChanged() might not work(you'll have to make another cursor).
    adapter.notifyDataSetChanged();
}

then in the bindView() method of your adapter, besides what you do, see if the selectedPosition is equal to the cursor row ID. If that is the case then search for the LinearLayout and make it visible:

//...
long theId = cursor.getLong(cursor.getColumnIndex("_id"));
if (theId == selectedPosition) {
       //this is the row that the user clicked, so show the extra stuff
       LinearLayout ll = (LinearLayout) view.findViewById(R.id.itemOptionsView);
       ll.setVisibility(View.VISIBLE);
} else {
       // implement this so you don't end up with a recycled view.
       LinearLayout ll = (LinearLayout) view.findViewById(R.id.itemOptionsView);
       ll.setVisibility(View.GONE);
}    
//...