Question

I am very new to Android development and Java. Have read around but I’m not getting anywhere on this issue.

I have a button which when clicked should set a variable A’s Value to “Item Purchased”.
However, I am only get the value used when the variable is first defined in the class.

For those learning like me on this – this topic will hopefully make an excellent reference to those just starting.

Code is:

public class shopView extends Activity
{

    String temp = "temp";

    @Override
    protected void onCreate(Bundle savedInstanceState) 
    {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.shopview);


        Button btnRef1 = (Button) findViewById(R.id.btnbtnRef11);
        final TextView ConfirmPurchasetest = (TextView) findViewById(R.id.tvMigName);

        btnRef1.setOnClickListener(new View.OnClickListener()
        {   
            @Override
            public void onClick(View v) {
                temp = "passed value";
                ConfirmPurchasetest.setText("item Purchased");
                buyFromShop();
                Log.v("after button push", "temp");
                };
        });

    }
    public String buyFromShop(){
        Log.v("button push", "after buy from shop");
        Log.v("temp variable",temp);
        return temp;
    }

}

and is called using the following:

shopcheckout = shop.buyFromShop();

Log.v("Value in myView",shopcheckout);

Expected: shopcheckout = “item purchased”
Actual: shopcheckout = “temp”

Thanks again for any answers. Will actively monitor this post.

Answer 1

Unless you click on your Button btnRef1, buyFromShop() will always return “temp”.

If you add this code in your onCreate():

temp = "Changing the string.";

Now buyFromShop() will return “Changing the string.”.

If you want buyFromShop() to return the value of ConfirmPurchasedtest, change your code to this:

public class shopView extends Activity
{
    TextView confirmPurchaseTest;
    String temp = "temp";

    @Override
    protected void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.shopview);

        Button btnRef1 = (Button) findViewById(R.id.btnbtnRef11);
        confirmPurchaseTest = (TextView) findViewById(R.id.tvMigName);

        btnRef1.setOnClickListener(new View.OnClickListener()
        {   
            @Override
            public void onClick(View v) {
                temp = "passed value";
                confirmPurchaseTest.setText("item Purchased");
                buyFromShop();
                Log.v("after button push", "temp");
            }
        });
    }

    public String buyFromShop(){
        Log.v("button push", "after buy from shop");
        Log.v("temp variable", temp);

        // Change this!
        return confirmPurchaseTest.getText().toString();
    }

}

Also according to naming convention, class names like shopView should have the first letter of each word capitalized; so ShopView. Variables like ConfirmPurchasetest should start with lower case and then capitalize each word (after the first), so confirmPurchaseTest.

Hope that helps!