In my quest to create a “Taxman” Android application I ran into the following problem:

I want to ask the user to enter their yearly income, after which the screen will flip and their after-tax income will be displayed in a table format for all Canadian provinces. (And for the future: all US states). The problem I ran into is creating a TableRow for each Canadian province in my main.xml. There are 13 provinces and territories, so 13 is not that bad to copy & paste in the main.xml; however, as soon as I have to copy & paste more than 2 times I start cringing and nausea kicks in. Personally I think “copy & paste” should not be in the programming vocabulary. Not only that, but I have 13 provinces now, what about when I have to enter 50 states! So, I had to find a way to create these new TableRow rows programmatically inside my TableLayout layout.

A great source for code snippets and answers to Android questions is http://www.anddev.org. I’m sure if you’re dabbling with Android then you’ve already come across this site. The particular post I read to do this is this one: Dynamically add rows to TableLayout. Commenters on that post were having problems getting this to work, but after I imported all the correct classes (android.widget.TableRow.LayoutParams is an important one to use) everything worked from the first time. I forced Eclipse to find most of the classes for me.

Below is the code from anddev.org, with my changes for my Taxman Android app. I’m too lazy to do a full-out beginning-to-end tutorial for this code snippet.

First I set my constants at the top of the Activity class:

public class Activity1 extends Activity implements OnTouchListener{

    int PROVINCE_Alberta = 0;
    int PROVINCE_BC = 1;
    int PROVINCE_Manitoba = 2;
    int PROVINCE_NewBrunswick = 3;
    int PROVINCE_Newfoundland = 4;
    int PROVINCE_Northwest = 5;
    int PROVINCE_NovaScotia = 6;
    int PROVINCE_Nunavut = 7;
    int PROVINCE_Ontario = 8;
    int PROVINCE_PEI = 9;
    int PROVINCE_Quebec = 10;
    int PROVINCE_Saskatchewan = 11;
    int PROVINCE_Yukon = 12;

    int numProvinces = 13;

There are 13 of them this time, there will be 50 of them for the States… technically this could be made into something much more malleable like an external config-type XML file.

Then in the onCreate method I created an array of String objects that will house all these provinces:

        String[] provinces = new String[numProvinces];
        provinces[PROVINCE_Alberta] = "Alberta";
        provinces[PROVINCE_BC] = "British Columbia";
        provinces[PROVINCE_Manitoba] = "Manitoba";
        provinces[PROVINCE_NewBrunswick] = "New Brunswick";
        provinces[PROVINCE_Newfoundland] = "Newfoundland and Labrador";
        provinces[PROVINCE_Northwest] = "Northwest Territories";
        provinces[PROVINCE_NovaScotia] = "Nova Scotia";
        provinces[PROVINCE_Nunavut] = "Nunavut";
        provinces[PROVINCE_Ontario] = "Ontario";
        provinces[PROVINCE_PEI] = "Prince Edward Island";
        provinces[PROVINCE_Quebec] = "Quebec";
        provinces[PROVINCE_Saskatchewan] = "Saskatchewan";
        provinces[PROVINCE_Yukon] =  "Yukon";

And right underneath that I create a TableRow for each item in the array provinces:

        // Get the TableLayout
        TableLayout tl = (TableLayout) findViewById(R.id.maintable);

        // Go through each item in the array
        for (int current = 0; current < numProvinces; current++)
        {
            // Create a TableRow and give it an ID
            TableRow tr = new TableRow(this);
            tr.setId(100+current);
            tr.setLayoutParams(new LayoutParams(
                    LayoutParams.FILL_PARENT,
                    LayoutParams.WRAP_CONTENT));   

            // Create a TextView to house the name of the province
            TextView labelTV = new TextView(this);
            labelTV.setId(200+current);
            labelTV.setText(provinces[current]);
            labelTV.setTextColor(Color.BLACK);
            labelTV.setLayoutParams(new LayoutParams(
                    LayoutParams.FILL_PARENT,
                    LayoutParams.WRAP_CONTENT));
            tr.addView(labelTV);

            // Create a TextView to house the value of the after-tax income
            TextView valueTV = new TextView(this);
            valueTV.setId(current);
            valueTV.setText("$0");
            valueTV.setTextColor(Color.BLACK);
            valueTV.setLayoutParams(new LayoutParams(
                    LayoutParams.FILL_PARENT,
                    LayoutParams.WRAP_CONTENT));
            tr.addView(valueTV);

            // Add the TableRow to the TableLayout
            tl.addView(tr, new TableLayout.LayoutParams(
                    LayoutParams.FILL_PARENT,
                    LayoutParams.WRAP_CONTENT));
        }

The main.xml contains the following for the TableLayout:

        <TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
                android:layout_width="fill_parent"
                android:layout_height="fill_parent"
                android:stretchColumns="0,1"
                android:id="@+id/maintable" >
        </TableLayout>

And here is the final result:

So far I have the Ontario taxes working :). If you make $50,000 in Ontario, you’d be taking home $38,285.53.