CODEWITHSUNDEEP
javaandroid
Grrrben
Grrrben

Reputation: 325

Hashmap not accessible

I am building an Android app where I download a XML file containing content to display on a GoogleMap. The info-windows are clickable, so to differentiate between the different windows I use a Hashmap.

Whenever the map loads it crashes with a NullPointerException. The hashmap is named markerEntryHashMap, here's some code:

private class DownloadXmlTask extends AsyncTask<String, Void, String> {

    /**
     * Hashmap with marker; String ids as key, entry obj as value
     */
    private HashMap<String, CurvitVacatureXmlParser.Entry> markerEntryHashMap;

    @Override
    protected String doInBackground(String... urls) {
        [...]
    }

    @Override
    protected void onPostExecute(String result) {

        for (CurvitVacatureXmlParser.Entry entry : mapEntries) {

            [...]

            Log.d(TAG, "Marker ID: " + m.getId()); // OK; Marker ID: m0
            Log.d(TAG, "Entry ID: " + entry.id); // OK; Entry ID: 12

            // there is no unique identifier in an info-window so I thought using the hashmap to differentiate later on in an OnInfoWindowClickListener
            // This crashes: FATAL EXCEPTION: main java.lang.NullPointerException
            markerEntryHashMap.put(m.getId(), entry);
        }

    }
}

Any of you guys/gals spot the mistake?

Upvotes: 0

Views: 95

Answers (2)

Prathmesh Swaroop
Prathmesh Swaroop

Reputation: 621

You have not initialized a HashMap , You can initialize it in onPreExecute or onPostExecute before for loop as below:

private class DownloadXmlTask extends AsyncTask<String, Void, String> {

    /**
     * Hashmap with marker; String ids as key, entry obj as value
     */
    private HashMap<String, CurvitVacatureXmlParser.Entry> markerEntryHashMap;

    @Override
    protected String doInBackground(String... urls) {
        [...]
    }

    @Override
    protected void onPostExecute(String result) {
         markerEntryHashMap=new  HashMap<String,CurvitVacatureXmlParser.Entry>();
        for (CurvitVacatureXmlParser.Entry entry : mapEntries) {

            [...]

            Log.d(TAG, "Marker ID: " + m.getId()); // OK; Marker ID: m0
            Log.d(TAG, "Entry ID: " + entry.id); // OK; Entry ID: 12

            // there is no unique identifier in an info-window so I thought using the hashmap to differentiate later on in an OnInfoWindowClickListener
            // This crashes: FATAL EXCEPTION: main java.lang.NullPointerException
            markerEntryHashMap.put(m.getId(), entry);
        }

    }
}

Upvotes: 1

Hamilton
Hamilton

Reputation: 152

You have to initialize your HashMap

Change 

private HashMap<String, CurvitVacatureXmlParser.Entry> markerEntryHashMap;

to

private HashMap<String, CurvitVacatureXmlParser.Entry> markerEntryHashMap = new HashMap<>();

Upvotes: 3

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