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POSubclassing an OnClickListener
 

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    <p>I'm trying to create a simple Calendar application in android, mostly for personal learning as I am new to Android (and Java for that matter). </p> <p>Basically, it's a ListView showing the current days of the month that, when clicked, opens a dialog asking for an event description. </p> <p>Obviously, this dialog has an OK button that when clicked should update the ListView with the input from the EditText.</p> <p>However, I'm having trouble getting the OnClickListener for the OK button to work, no matter what I try, I get a NullPointerException on the line where I set it.</p> <pre><code>public class SimpleCalendar extends ListActivity { public static Context appContext; public static int nMonthChoice = CalendarIO.myCalendar.get(Calendar.MONTH); private static ArrayAdapter aAd; private static String[] ArrayOfDays; final private static String[] dayNames = {"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"}; Dialog userInput; int currentDay; EditText dialogInput; @Override public void onCreate(Bundle icicle) { super.onCreate(icicle); appContext = this; TextView tv = new TextView(this); CalendarIO.initCalendar(tv); CalendarIO.myCalendar.set(Calendar.MONTH, nMonthChoice); updateMonth(); aAd = new ArrayAdapter(this, R.layout.main, ArrayOfDays); setListAdapter(aAd); ListView lv = getListView(); lv.setTextFilterEnabled(true); lv.setOnItemClickListener(new OnItemClickListener() { public void onItemClick(AdapterView&lt;?&gt; parent, View view, int position, long id) { LinearLayout dialogLayout = (LinearLayout) findViewById(R.id.dLL); currentDay = position + 1; dialogInput = (EditText) findViewById(R.id.dET); userInput = new Dialog(appContext); userInput.setContentView(R.layout.dialog); userInput.setTitle("New Event"); Button dBtn = new Button(appContext); dBtn.setOnClickListener(new View.OnClickListener() { public void onClick(View v) { userInput.dismiss(); CalendarIO.myCalendar.set(Calendar.DAY_OF_MONTH, currentDay); SimpleCalendar.updateMonth(); CalendarIO.CalendarEvents.put(CalendarIO.myCalendar.get(Calendar.DAY_OF_YEAR), dialogInput.getText()); SimpleCalendar.aAd = new ArrayAdapter(appContext, R.layout.main, ArrayOfDays); setListAdapter(SimpleCalendar.aAd); }}); dialogLayout.addView(dBtn); userInput.show(); } }); } public static void updateMonth() { int nCounter, nDaysInMonth; String sCurrentEvent; String currentDay; nDaysInMonth = CalendarIO.myCalendar.getActualMaximum(Calendar.DAY_OF_MONTH); ArrayOfDays = new String[nDaysInMonth]; for (nCounter = 0; nCounter &lt; nDaysInMonth; nCounter++) { CalendarIO.myCalendar.set(Calendar.DAY_OF_MONTH, nCounter + 1); sCurrentEvent = (String) CalendarIO.CalendarEvents.get( CalendarIO.myCalendar.get(Calendar.DAY_OF_YEAR)); currentDay = dayNames[CalendarIO.myCalendar.get(Calendar.DAY_OF_WEEK) - 1]; ArrayOfDays[nCounter] = currentDay + ", " + MonthView.monthNames[nMonthChoice] + " " + (nCounter + 1); try { if (!sCurrentEvent.equals("")) { ArrayOfDays[nCounter] += ("\t- " + sCurrentEvent + "\n"); } } catch (NullPointerException e) {//don't do anything} } } } } </code></pre> <p>I know the code is a little unreadable but I hope you'll bear through it. I'm also planning on cleaning up some of the global variables later..</p> <p>Anyway, these are the main two methods for input. updateMonth() turns a hash map from my CalendarIO class into a String Array, and of course, onCreate is my main Activity method.</p> <p>When I run it, ADB gives me:</p> <pre><code>17:51:53.814 22161 ERROR AndroidRuntime FATAL EXCEPTION: main 17:51:53.814 22161 ERROR AndroidRuntime java.lang.NullPointerException 17:51:53.814 22161 ERROR AndroidRuntime at org.me.simplecalendar.SimpleCalendar$1.onItemClick(SimpleCalendar.java:80) </code></pre> <p>Line 80 is <code>dialogLayout.addView(dBtn);</code></p> <p>This was my latest attempt: trying to add a newly created button to my XML defined LinearLayout.</p> <p>I've also tried having the button defined in XML and just adding a listener to it. That also complains about an NPE.</p> <p>Also, I've tried defining the listener in XML as well and pointing it to a method in the class, but it throws an error saying that it can't find my method in the ComponentInfo class, which is a little bizarre - but I'm sure it's just something I haven't learned yet.</p> <p>I'm at the end of my attempts.</p> <p>Any suggestions would be very appreciated.</p>
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