Need to set additional information in list view - android-layout

Question

I am trying to created a listview containing filenames. I want to set a additional information like file id with each list items, so when i click a filename, i have to get file id from it. please help me do this.
My sample code:
ListView listview = (ListView) findViewById(R.id.listview);
ArrayAdapter fileListAdapter = new ArrayAdapter(this, android.R.layout.simple_list_item_1, ['one','two','three']);
listview.setAdapter(fileListAdapter);

Answer 1

There are quite a few things involved here, so i'm providing you with an example of how you can achieve this (you can copy-paste and test):
public class MainActivity extends ListActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// First we simulate a pool of file names and IDs
String[] fileNames = {"fileName1", "fileName2", "fileName3"};
List<Integer> fileNameIds = new ArrayList<Integer>();
fileNameIds.add(1200);
fileNameIds.add(356);
fileNameIds.add(28);
// We call our custom Adapter
ArrayAdapter<String> adapter = new CustomAdapter(this, fileNames, fileNameIds);
// Finally we set the adapter to our list
setListAdapter(adapter);
}
// This is a custom adapter that uses ArrayAdapter for our purpose
// (as this is just an example you should consider using Base Adapter if you don't want
// to have a pool of filenames and a separate pool of ids)
class CustomAdapter extends ArrayAdapter<String>{
private final LayoutInflater INFLATER;
private final String[] FILE_NAMES;
private final List<Integer> FILE_NAME_IDS;
public CustomAdapter(Context context, String[] fileNames, List<Integer> fileNameIds) {
super(context, R.layout.custom_row, fileNames);
this.INFLATER = LayoutInflater.from(context);
this.FILE_NAMES = fileNames;
this.FILE_NAME_IDS = fileNameIds;
}
// HERE is where you can assign effectively an ID to your rows
#Override
public View getView(int position, View convertView, ViewGroup parent) {
// this is an object that takes advantage of the holder pattern
// it retains the state of our rows in the list
FileNameHolder holder;
if(convertView == null){
convertView = INFLATER.inflate(R.layout.custom_row, null); // inflate your custom row
// now you need to assign specific identifier to the list row that the holder will retain
// for you, so you can always get this id by calling getTag from the View object on your
// item click listeners
holder = new FileNameHolder();
holder.fileName = (TextView) convertView; //since i only have a texView in layout i don't need to call findByView
convertView.setTag(holder); // relate the view to a custom FileNameHolder object that retains file name and its ID
} else{
holder = (FileNameHolder) convertView.getTag();
}
holder.fileName.setText(FILE_NAMES[position]); // PROVIDE the list with file name description
holder.idFileName = FILE_NAME_IDS.get(position); // ASSIGN file name ID
return convertView;
}
}
// This is an example of catching a row clicked and get the custom ID that you assigned,
// from here you can use that ID as you need
#Override
protected void onListItemClick(ListView l, View v, int position, long id) {
// Here as you can see we obtain the object associated with the row that was clicked
FileNameHolder holder = (FileNameHolder) v.getTag();
// Here i provide a way you can test that you're always getting the correct file name and Id
Toast.makeText(this,
"File Name = " + holder.fileName.getText() +
", File ID = " + holder.idFileName,
Toast.LENGTH_SHORT).show();
}
// This is a class that takes advantage of the Holder Pattern and we use it to
// achieve what you need (remember this is just an example you should consider
// changing class and member access modifiers as you need)
class FileNameHolder{
Integer idFileName;
TextView fileName;
FileNameHolder() {
}
}
}
custom_row.xml is just a TextView (i took it from the simple_list_item_1 layout):
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#android:id/text1"
android:layout_width="match_parent"
android:layout_height="?android:attr/listPreferredItemHeight"
android:paddingStart="?android:attr/expandableListPreferredItemPaddingLeft"
android:textAppearance="?android:attr/textAppearanceMedium"
android:gravity="center_vertical"
/>
Hope it's useful... regards!!