android, bad resaults in use of array adapter

Question

I have a String array and I want to show its items in a list. I have a row.xml which contains a table and in each row i have three TextView. The things that i want is, showing each three items of array in each row.

sample: String[] str = {"1", "2", "3", "4", "5", "6"}; Each row should be like this:

str[1]----str[2]----str[3]
str[4]----str[5]----str[6]

my xml code is:

<?xml version="1.0" encoding="utf-8"?>

<TableLayout 
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:shrinkColumns="*"  
android:stretchColumns="*" >
    <TableRow 
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:gravity="center_horizontal"
    android:layout_marginTop="10dip"
    android:layout_marginBottom="10dip" >
        <TextView
            android:id="@+id/outstanding_contractdate"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textColor="#ffffff"
            android:textSize="15sp" />
        <TextView
            android:id="@+id/outstanding_contractno"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textColor="#ffffff"
            android:textSize="15sp" />
        <TextView
            android:id="@+id/outstanding_contractamount"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentRight="true"
            android:textColor="#ffffff"
            android:textSize="15sp" />
    </TableRow>

</TableLayout>

in OnCreate() i put(I have some other views and a listView):

lvOutstanding = (ListView) findViewById(R.id.outstanding_list);
lvOutstanding.setAdapter(new MyListAdapter());

and this is my adapter:

class MyListAdapter extends ArrayAdapter<String>{
        MyListAdapter(){
            super(MSOutStanding.this, R.layout.list_outstanding, tokens);
        }

        public View getView(int position, View convertView, ViewGroup parent){
            View row = convertView;

            //String str = llData.get(position);
            //String[] tokens = str.split(",");

            if(row == null){
                LayoutInflater inflater = getLayoutInflater();
                row = inflater.inflate(R.layout.list_outstanding, parent, false);
            }

            TextView tvContDate = (TextView) row.findViewById(R.id.outstanding_contractdate);
            TextView tvContNo = (TextView) row.findViewById(R.id.outstanding_contractno);   
            TextView tvContAmount = (TextView) row.findViewById(R.id.outstanding_contractamount);

            tvContDate.setText(tokens[0]);
            tvContNo.setText(tokens[1]);
            tvContAmount.setText(tokens[2]);

            return(row);
        }
    }

My first problem is, i don't see result as i want. and the second is, i have defined "tokens" as string array in top of my class (private static String[] tokens = {"", "", ""};) in this way, when i run the application, it shows me three rows with same results. but if i change definition such as Private static String[] tokens; the program crashes. I got headache :( if it's possible tell me where is my fault?

Thanks

Answer 1

When you use:

static String[] tokens;

instead of:

static String[] tokens = { "", "", "" };

tokens isn't initialised, meaning tokens[n] is null, causing a crash. In your comments, doing tokens[position * count + 1] will quickly go out of the bounds of the array - if you used tokens = { "", "", "" } as above, there are only 3 elements inside the array.

When you pass tokens into the super constructor with this line:

super(MSOutStanding.this, R.layout.list_outstanding, tokens);

You're saying that there should be 3 rows in the list, since there are 3 elements in the array. For the 3rd item, position = 3 * count = 3 == boom goes the array.

One way to solve: Pass an array (or ArrayList) of objects into the super constructor:

public class Contract {
        String date;
        String no;
        String amount;

        Contract(String d, String n, String a) {
            date = d;
            no = n;
            amount = a;
        }    
    }

Contract[] contracts = { new Contract("1", "2", "3"), new Contract("4", "5", "6") };
    class MyListAdapter extends ArrayAdapter<Contract>{
         MyListAdapter(){
                super(MSOutStanding.this, R.layout.list_outstanding, contracts);
            }
    }
    ...

    public View getView(int position, View convertView, ViewGroup parent){
        ...
        Contract c = getItem(position);
        tvContDate.setText(c.date);
        tvContNo.setText(c.no);
        tvContAmount.setText(c.amount);
...
    }