Binding object to listview

Question

I want to bind some data gotten from a web service to a custom listview... My listview has one imageview and three textviews...

Most of the tutorials I've read on it suggest that an adapter class should be made, so I've currently written an adapter like below:

public class InboxAdapter extends BaseAdapter {

    private Context context;

    private List<MailInbox> mails;

    public InboxAdapter(Context context, List<MailInbox> mails)
    {
        this.context = context;
        this.mails = mails;
    }

    @Override
    public int getCount() {
        // TODO Auto-generated method stub
        return mails.size();
    }

    @Override
    public Object getItem(int item) {
        // TODO Auto-generated method stub
        return mails.get(item);
    }

    @Override
    public long getItemId(int position) {
        // TODO Auto-generated method stub
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup viewGroup) {

        MailInbox entry = mails.get(position);

        if(convertView == null)
        {
            LayoutInflater inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = inflater.inflate(R.layout.mail_list_row, null);
        }

        ImageView mailImg = (ImageView)convertView.findViewById(R.list.mail_thumb);
        //Set the appropriate image - either unread or read

        TextView author = (TextView)convertView.findViewById(R.list.mail_text);
        TextView body = (TextView)convertView.findViewById(R.list.mail_detail);
        TextView date = (TextView)convertView.findViewById(R.list.mail_date);

        author.setText(entry.AuthorName);
        body.setText(entry.MessageBody);
        date.setText(entry.CreatedAt);

        return convertView;
    }
}

So this is this part where I'm stuck.. I now have an adapter, but I'm not completely sure how to use it...

In the activity that has the listview:

Update:

Okay, so I'm trying to fill the adapter like this:

private void setUpList()
{
    list = (ListView)findViewById(R.id.mail_list);      

    final List<MailInbox> mails = new ArrayList<MailInbox>();

    for(int i = 0; i < mMessages.myMail.size(); i++)
    {
        MailInbox inbox = new MailInbox();

        inbox.setProperty(0, mMessages.myMail.get(i).CreatedAt);
        inbox.setProperty(1, mMessages.myMail.get(i).MessageBody);
        inbox.setProperty(3, mMessages.myMail.get(i).AuthorName);
        inbox.setProperty(4, mMessages.myMail.get(i).IsRead);//used to determine the image that will be in the imageview

        mails.add(inbox);
    }

    // Just to check if it's added properly - it outputs 5
    int length = mails.size();
    System.out.println("Size: " + length);

    InboxAdapter adapter = new InboxAdapter(this, mails);

    list.setAdapter(adapter);
}

But on list.setAdapter(adapter), I get a Nullpointer exception

Entire error:

05-14 17:43:17.855: E/AndroidRuntime(976): FATAL EXCEPTION: main
05-14 17:43:17.855: E/AndroidRuntime(976): java.lang.NullPointerException
05-14 17:43:17.855: E/AndroidRuntime(976):  at com.cim.daycare.InboxActivity.setUpList(InboxActivity.java:67)
05-14 17:43:17.855: E/AndroidRuntime(976):  at com.cim.daycare.InboxActivity.access$2(InboxActivity.java:43)
05-14 17:43:17.855: E/AndroidRuntime(976):  at com.cim.daycare.InboxActivity$GetMails.onPostExecute(InboxActivity.java:96)
05-14 17:43:17.855: E/AndroidRuntime(976):  at com.cim.daycare.InboxActivity$GetMails.onPostExecute(InboxActivity.java:1)
05-14 17:43:17.855: E/AndroidRuntime(976):  at android.os.AsyncTask.finish(AsyncTask.java:417)
05-14 17:43:17.855: E/AndroidRuntime(976):  at android.os.AsyncTask.access$300(AsyncTask.java:127)
05-14 17:43:17.855: E/AndroidRuntime(976):  at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:429)
05-14 17:43:17.855: E/AndroidRuntime(976):  at android.os.Handler.dispatchMessage(Handler.java:99)
05-14 17:43:17.855: E/AndroidRuntime(976):  at android.os.Looper.loop(Looper.java:123)
05-14 17:43:17.855: E/AndroidRuntime(976):  at android.app.ActivityThread.main(ActivityThread.java:3683)
05-14 17:43:17.855: E/AndroidRuntime(976):  at java.lang.reflect.Method.invokeNative(Native Method)
05-14 17:43:17.855: E/AndroidRuntime(976):  at java.lang.reflect.Method.invoke(Method.java:507)
05-14 17:43:17.855: E/AndroidRuntime(976):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
05-14 17:43:17.855: E/AndroidRuntime(976):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
05-14 17:43:17.855: E/AndroidRuntime(976):  at dalvik.system.NativeStart.main(Native Method)

From doing a bit of Google'ing, it sounds like the problem might lie with the xml-files... I have two xml's, one called mail_list and one called mail_list_row...

list:

<?xml version="1.0" encoding="utf-8"?>
<ListView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/mail_list"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:layout_weight="2"
    android:drawSelectorOnTop="false" >    
</ListView>

row:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="48dip"
    android:background="@drawable/listselector"
    >
    <ImageView
        android:id="@+list/mail_thumb"
        android:layout_width="30dip"
        android:layout_height="30dip"
        android:layout_centerVertical="true"
        android:layout_alignParentLeft="true"
        android:contentDescription="@string/imgdesc"
        />
    <TextView
        android:id="@+list/mail_text"
        android:layout_toRightOf="@+list/mail_thumb"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="14dip"
        android:layout_marginLeft="8dip"
        android:layout_centerVertical="false"
        android:singleLine="true"
        android:ellipsize="end"
        android:textStyle="bold"
        android:textColor="@android:color/white"
        />
    <TextView 
        android:id="@+list/mail_detail"
        android:layout_toRightOf="@+list/mail_thumb"
        android:layout_below="@+list/mail_text"
        android:layout_width="100dip"
        android:layout_height="wrap_content"
        android:textSize="12dip"
        android:layout_marginLeft="8dip"
        android:layout_centerVertical="false"
        android:singleLine="true"
        android:ellipsize="end"
        android:textColor="@color/grey"     
        />
    <TextView 
        android:id="@+list/mail_date"
        android:layout_toRightOf="@+list/mail_detail"
        android:layout_below="@+list/mail_text"
        android:layout_width="100dip"
        android:layout_height="wrap_content"
        android:textSize="12dip"
        android:singleLine="true"
        android:ellipsize="end"
        android:textColor="@color/grey"
        android:layout_alignParentRight="true"      
        />
</RelativeLayout>

Answer 1

try something like

private void setUpList()
{
    list = (ListView)findViewById(R.id.mail_list);
     InboxAdapter adapter=new InboxAdapter(this,YourArrayList);
    list.setAdapter(adapter);
}

Answer 2

In the setUpList method you are passing the data you would like to use into the adapter.

The constructor then assigns them collections to the collections within the adapter. The getView then pulls the relevant data (1 by 1) and puts it in the correct element of your view