Question

I have to create a list whose list items have 2 lines of text. I started building a custom list item, but then I discovered the TwoLineListItem component. I wrote this code:

pageFilterResultView=new TwoLineListItem(containerActivity);
pageFilterResultView.getText1().setText("Test");

However, getText1 returns null, and the second line throws a NullPointerException. So I thought I need to use an inflated layout instead of a constructor. The TwoLineListItem documentation specifies I can use the android.R.layout.two_line_list_item resource for the layout, so I changed the code to:

LayoutInflater inflater=(LayoutInflater)containerActivity.
        getSystemService(Context.LAYOUT_INFLATER_SERVICE);
pageFilterResultView=(TwoLineListItem)inflater.inflate(android.R.
        layout.two_line_list_item,null);
pageFilterResultView.getText1().setText("Test");

However, this throws a ClassCastException because the layout is actually a LinearLayout. TwoLineListItem inherits from RelativeLayout, so I can’t even cast the layout to a higher class in the hierarchy.

So the question is: How do I use TwoLineListItem correctly? Do I have to create my own custom layout for it? If so, what’s the point of this component if I still have to do all the work of creating a list item by myself?

Answer 1

How do I use TwoLineListItem correctly?

The TwoLineListItem widget is a facade over two TextViews that have to be provided by you. To use the TwoLineListItem in a ListView‘s row you’ll need a row layout where you have the TwoLineListItem widget with two(at least) TextView children with specific ids(android.R.id.text1 and android.R.id.text2). Something like this:

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

    <TextView
        android:id="@android:id/text1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

    <TextView
        android:id="@android:id/text2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" 
        android:layout_below="@android:id/text1"/>

</TwoLineListItem>

Then you can use it in the getView() method like you did:

pageFilterResultView=(TwoLineListItem)inflater.inflate(R.layout.the_layout_file_above,null);
pageFilterResultView.getText1().setText("Test");

Of course you have the possibility of using an included layout file as the child of the TwoLineListItem(as long as you have the two TextViews with the required ids):

<?xml version="1.0" encoding="utf-8"?>
<TwoLineListItem xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >
    <!-- the android version of the two line layout -->
    <include layout="@android:layout/two_line_list_item" />

</TwoLineListItem>

but this just increases the layout depth and should be avoided.

If so, what’s the point of this component if I still have to do all
the work of creating a list item by myself?

Judging by the fact that you can’t use this widget programmatically, I don’t see the need for this component either.