Question

There is a ListView in layout of my Activity.
listview_layout.xml

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

    <ListView android:layout_width="wrap_content"    
        android:layout_height="wrap_content"    
        android:id="@+id/MyListView" />
</LinearLayout>

I am using another layout for ListItem of ListView.

listitem_layout.xml

<?xml version="1.0" encoding="utf-8"?>  
<RelativeLayout    
    android:id="@+id/RelativeLayout01"    
    android:layout_width="fill_parent"    
    xmlns:android="http://schemas.android.com/apk/res/android"    
    android:layout_height="fill_parent">  

    <TextView
        android:id="@+id/txtTitle"
        android:layout_width="80dp"
        android:layout_height="wrap_content" />

    <Spinner 
        android:id="@+id/MySpinner"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

</RelativeLayout>  

My Activity’s layout is the same with the listview_layout.xml’s.

I use SimpleAdapter cited the layout of listitem_layout.xml.

The problwm: Now I want to get the Spinner control ID of listview_layout.xm.

I use findViewById(MySpinner) in activity of ListView, it has the error of null pointer exception.
can not find. Because the Activity layout files use the listview_layout.xml’s and Spinner control in listview_layout.xml.

anyone’s help is very thankful.

Answer 1

you cannot directly use the findViewById(spinnerId). You have to override the getView() method of Custom Adapter instead of Simple Adapter and inside that inflate the listitem_layout to a view(v) and then use v.findViewById(spinnerId).

Refer the below link which will help you in creating custom adapter (Weather Adapter in the link’s example). in the example ImageView object is created in the GetView method. Instead of that you use Spinner.