Get data from server using of AsyncTask

Question

In my program a number of values are stored on the server. I read these data using of the AsyncTask class from the server.

This is my code:

public class TestActivity extends AppCompatActivity {
    private static List<String> mPackName;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mPackName = new ArrayList<>();
        try {
            boolean check = new GetDataAsyncTask().execute("1234567").get();
        } catch (InterruptedException e) {

        } catch (ExecutionException e) {
            e.printStackTrace();
            e.printStackTrace();
        }

    }

    private class GetDataAsyncTask extends AsyncTask<String, Void, Boolean> {

        @Override
        protected Boolean doInBackground(String... params) {
            final String mCode = params[0];

            APIGettingPosts apiGettingPosts = new APIGettingPosts(TestActivity.this, "get_off_code.php");
            apiGettingPosts.getOffCode(new APIGettingPosts.OnOffCodeReceived() {
                @Override
                public void onReceived(List<Posts> posts) {
                    if (!(posts == null || posts.isEmpty()))
                        for (int i = 0; i < posts.size(); ++i) {
                            mPackName.add(posts.get(i).getTitle());
                            Log.e("mPackName["+String.valueOf(i)+"]",mPackName.get(i));
                        }
                }
            });
            Log.e("Size of mPackName: ", String.valueOf(mPackName.size()));

            for (int i = 0; i < mPackName.size(); ++i)
                if (mCode.equals(mPackName.get(i))) {
                    Log.e("Is Equal: ", mPackName.get(i));
                    return true;
                }
            return false;
        }
    }
}

The program correctly receives the data from the server and stores it in the mPackName list. At the end of the doInBackground function, the program checks if the input value in the GetDataAsyncTask().execute("1234567") function exists in the mPackName list, returns the true value.

Although the input value of the GetDataAsyncTask().execute("1234567") function is in the mPackNamelist, the program returns the false value.

The Log cat output is as follows:

08-28/com.green E/Size of mPackName:: 0

08-28/com.green E/mPackName[0]: 1234567

08-28/com.green E/mPackName[1]: QAZXSWE

08-28/com.green E/mPackName[2]: QWERTYU

The size of the mPackName list is also zero in Log cat , although it has three values {'1234567','QAZXSWE','QWERTYU'}.

The question is: How do I search '1234567' value in the mPackName list to return the true value in check = new GetDataAsyncTask().execute("1234567").get(); code?

Answer 1

Edited Answer

Looks like you even don't need AsyncTask as getOffCode method already runs in background thread.

Remove GetDataAsyncTask class and create a method like below.

private void search(final SearchCallback callback) {
    APIGettingPosts apiGettingPosts = new APIGettingPosts(TestActivity.this, "get_off_code.php");
    apiGettingPosts.getOffCode(new APIGettingPosts.OnOffCodeReceived() {
        @Override
        public void onReceived(List<Posts> posts) {
            if (!(posts == null || posts.isEmpty())) {
                for (int i = 0; i < posts.size(); ++i) {
                    mPackName.add(posts.get(i).getTitle());
                    Log.e("mPackName[" + String.valueOf(i) + "]", mPackName.get(i));
                    if (mCode.equals(mPackName.get(i))) {
                        callback.onSearchFound(true);
                        break;
                    }
                }
            }
            callback.onSearchFound(false);
        }
    });
}

public interface SearchCallback{
    void onSearchFound(boolean success);
}

Then call from onCreate method like below

search(new SearchCallback(){
    @Override
    public void onSearchFound(boolean success) {

    }
});

Answer 2

Try placing a switch in the onPostExecute() method.

EG.

...

private class GetDataAsyncTask extends AsyncTask<String, Void, Boolean> {

@Override
void onPostExecute(Object o){
    handleResults()
}

...

void handleResults(){
// Insert your check here
}