Question

I’m using AsyncTask to fetch information from a website for a small learning project I’m doing. I’ve tried my code, and it “tries” do to what I intend it to do, though I have a small problem.

I’m passing a String as parameter to execute in AsyncTask, but the parameter is referenced by address instead of value. Why is this, and how do I pass a parameter between the UI thread and the background thread properly?

This is my code where the parameter is passed:

ibSearch.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            Editable artnrInput = input.getText();
            String artnr = artnrInput.toString();
            new Connection().execute(artnr);
        }
    });

I’ve debugged it so far and the parameter “artnr” is a value here.

This is part of my AsyncTask where the error occurs:

public class Connection extends AsyncTask<String, String, String>{

    @Override
    protected String doInBackground(String... artnr)  {
        String url = "http://mobil.systembolaget.se/SokDryck/SokDryck.aspx?artnr="+ artnr + "&lan=01";

What I want my String url to look like is this for example:
http://mobil.systembolaget.se/SokDryck/SokDryck.aspx?artnr=221101&lan=01

What it does like when I debug it, making it not work is this:

 http://mobil.systembolaget.se/SokDryck/SokDryck.aspx?artnr=[Ljava.lang.String;@43e4c9f8&lan=01

I have tried a simple toString(), but it was more of a guess. Why is it not passed as a value, but a reference?

Thank you,
Z

Answer 1

You should use artnr[0] (which is the only parameter you are passing) instead of artnr (since String... artnr is an array of String objects not a single String object):

String url = "http://mobil.systembolaget.se/SokDryck/SokDryck.aspx?artnr="+ artnr[0] + "&lan=01";

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Aside to that, see How Java passes objects as arguments by value