AsyncTask methods: I get error whether I write "@Override" annotation or not

Question

I am writing an Android client for consuming a SOAP based web service. I am using an AsyncTask for performing the networking (that is calling the webservice) operation. I am in the middle of writing the client.

Now as I try to implement the AsyncTask's doInBackground method, I get the following two errors at protected String doInBackground(String[] params)... if I write the @Override annotation with it:

The method doInBackground(String[]) of type MainActivity.MyTask must override or implement a supertype method. 1 Quick fix: Remove '@Override' annotation

and the following error at private class MyTask extends AsyncTask... :

The type MainActivity.MyTask must implement the inherited abstract method AsyncTask.doInBackground(String[]...). 2 Quick fixes: Add unimplemented methods (this auto-generates the doInBackground method again with the @Override annotation). Make type 'MyTask' abstract.

if I don't write the @Override annotation, I get only the second error.

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

        String [] params = {URL, METHOD_NAME, NAMESPACE}; 
    }

    private class MyTask extends AsyncTask<String[], Void, String> {

        //@Override write it or not write it? :s ****************
        protected String doInBackground(String[] params) {
            // TODO Auto-generated method stub
            return null;
        }
    }
...

What might be the reason behind this? What should I do?

Change `private class MyTask extends AsyncTask` to `private class MyTask extends AsyncTask` and write `String...` instead of `String[]` in `doInBackground argments` — MysticMagicϡ, Nov 15 '14 at 12:20

score 7 · Accepted Answer · answered Nov 15 '14 at 12:23

7

You have syntax error:

Change

private class MyTask extends AsyncTask<String[], Void, String>

to

private class MyTask extends AsyncTask<String, Void, String>

and write String... instead of String[] in doInBackground arguments.

protected String doInBackground(String... params) {
    // TODO Auto-generated method stub
    return null;
}

Hope this helps.

answered Nov 15 '14 at 12:23

MysticMagicϡ

28,593
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@BlazeTama Its converted to String[] at last.. [See here](http://stackoverflow.com/a/4211138/1777090) – MysticMagicϡ Nov 16 '14 at 09:51

score 2 · Answer 2 · answered Nov 15 '14 at 12:21

2

Since the method in AsyncTask<String[], Void, String> is declared as doInBackground(String[]... params) - possibly after substituting in the right type parameter, you need to have the same parameter types when you overrride it in MyTask. It looks like you've written doInBackground(String[] params) instead of doInBackground(String[]... params).

Note that that would mean that params would be a whole sequence of arrays of Strings. That may not be what you want. Did you really mean for MyTask to extend AsyncTask<String[], Void, String>?

answered Nov 15 '14 at 12:21

Dawood ibn Kareem

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Oh my bad, it should rather have been a varargs `doInBackground(String... params)`, I believe because the `AsyncTask` class itself which is the super type must be having a vararg argument in its `doInBackground`. Doesn't matter in my program even though I am passing a String array, because varargs are treated just like arrays I believe. Thank you, this solves my problem. – Solace Nov 15 '14 at 12:30
1

If you want to pass `String... params` here, then you probably want to change `MyTask` so that it extends `AsyncTask` as given in MysticMagic's answer. – Dawood ibn Kareem Nov 15 '14 at 12:32

score 1 · Answer 3 · answered Nov 15 '14 at 12:24

1

The doInBackground method should be written as

doInBackground(Params... params)

answered Nov 15 '14 at 12:24

javawocky

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How will that help, when the compile error states that the class has to implement `AsyncTask.doInBackground(String[]...)`? – Dawood ibn Kareem Nov 15 '14 at 12:26
Params being meant as a general placeholder here, not that he should write that explicitly instead of String[]... I should have been clearer – javawocky Nov 15 '14 at 12:29

AsyncTask methods: I get error whether I write "@Override" annotation or not

3 Answers3