I am trying to use a custom spinner for my calender view. I have written my own custom adapter. The view loads fine initially but as soon as I try to click on one of the items in the spinner dropdown the app crashes.
Following is my Activity code :
public class CalendarEventsActivity extends Activity {
protected ActivityHeader mHeader;
private Spinner mMonthDropdown;
@Override
protected void beforeMainContentCreated(Bundle savedInstanceState) {
}
public void onCreateMainContent(Bundle savedInstanceState) {
super.onCreateMainContent(savedInstanceState);
setRequestedOrientationByResourceID(R.integer.allow_landscape_calendar_events_activity);
getWindow().setBackgroundDrawable(null);
setContentView(R.layout.activity_calendar_events);
mHeader = (ActivityHeader) findViewById(R.id.header);
getSlidingMenu().setSlidingEnabled(false);
setupMonthSpinner();
}
private void setupMonthSpinner() {
mMonthDropdown = (Spinner) findViewById(R.id.month_spinner);
String[] items = new String[] { "January", "February", "March",
"April", "May", "June", "July", "August", "September",
"October", "November", "December" };
mMonthDropdown.setAdapter(new MyAdapter(this, R.layout.calendar_month_item, items));
mMonthDropdown.setOnItemSelectedListener(new OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view,
int position, long id) {
System.out.println("you have now clicked......."+((TextView)parent.getChildAt(position)).getText().toString());
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
// TODO Auto-generated method stub
}
});
}
public class MyAdapter extends ArrayAdapter<String> {
String[] calendar_months;
public MyAdapter(Context context, int textViewResourceId,
String[] objects) {
super(context, textViewResourceId, objects);
this.calendar_months = objects;
}
@Override
public View getDropDownView(int position, View convertView,
ViewGroup parent) {
return getCustomView(position, convertView, parent);
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
return getCustomView(position, convertView, parent);
}
public View getCustomView(int position, View convertView,
ViewGroup parent) {
LayoutInflater inflater = getLayoutInflater();
View row = inflater.inflate(R.layout.calendar_month_item, parent, false);
TextView label = (TextView) row.findViewById(R.id.calendar_month);
label.setText(calendar_months[position]);
return row;
}
}
}
This is xml where I am defining my layout for the Activity (activity_calendar_events.xml) :
<?xml version="1.0" encoding="utf-8"?>
<com.android.ui.ActivityHeader
android:id="@+id/header"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:gravity="center"
app:actionButtonDrawable="@drawable/icon_add_member_inset"
app:actionButtonDrawableHeight="35dp"
app:actionButtonDrawableWidth="35dp"
app:headerLabel="@string/calendar_events_header"
app:menuButtonDrawable="@drawable/icon_navbar_back_inset"
app:menuButtonDrawableHeight="35dp"
app:menuButtonDrawableWidth="35dp"
app:showMenuButton="true" />
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#F4F4F4"
android:orientation="horizontal"
android:layout_below="@+id/header" >
<Spinner
android:id="@+id/month_spinner"
android:layout_width="100dp"
android:layout_height="50dp"
android:layout_alignParentLeft="true"
android:layout_marginLeft="20dp"
android:background="#F4F4F4"
android:spinnerMode="dropdown"
android:popupBackground="#F4F4F4"/>
<TextView
android:id="@+id/calendar_year"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_marginRight="20dp"
android:text="2016" />
</RelativeLayout>
Here is the xml where I am defining the layout for the individual rows of the dropdown (calendar_month_item.xml) :
<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res/com.android.calendar"
android:id="@+id/calendar_month"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingBottom="8dp"
android:paddingLeft="15dp"
android:paddingTop="8dp"
android:textColor="#181512"
android:textSize="15sp"
android:textStyle="normal" />
And finally the Logcat error :
04-19 14:27:06.073: E/ThisLife(13008): java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.CharSequence android.widget.TextView.getText()' on a null object reference
04-19 14:27:06.073: E/ThisLife(13008): at com.android.calendar.CalendarEventsActivity$1.onItemSelected(CalendarEventsActivity.java:78)
04-19 14:27:06.073: E/ThisLife(13008): at android.widget.AdapterView.fireOnSelected(AdapterView.java:914)
04-19 14:27:06.073: E/ThisLife(13008): at android.widget.AdapterView.dispatchOnItemSelected(AdapterView.java:903)
04-19 14:27:06.073: E/ThisLife(13008): at android.widget.AdapterView.access$300(AdapterView.java:48)
04-19 14:27:06.073: E/ThisLife(13008): at android.widget.AdapterView$SelectionNotifier.run(AdapterView.java:873)
04-19 14:27:06.073: E/ThisLife(13008): at android.os.Handler.handleCallback(Handler.java:739)
04-19 14:27:06.073: E/ThisLife(13008): at android.os.Handler.dispatchMessage(Handler.java:95)
04-19 14:27:06.073: E/ThisLife(13008): at android.os.Looper.loop(Looper.java:135)
04-19 14:27:06.073: E/ThisLife(13008): at android.app.ActivityThread.main(ActivityThread.java:5343)
04-19 14:27:06.073: E/ThisLife(13008): at java.lang.reflect.Method.invoke(Native Method)
04-19 14:27:06.073: E/ThisLife(13008): at java.lang.reflect.Method.invoke(Method.java:372)
04-19 14:27:06.073: E/ThisLife(13008): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:905)
04-19 14:27:06.073: E/ThisLife(13008): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:700)
I believe this is a pretty standard way for writing custom spinners. I tried debugging with breakpoints and all the data points at the specific line causing the NPE seem to be not null. I am not really sure whats going on here. Any suggestions would be helpful.
Thanks.
Change the line
System.out.println("you have now clicked......."+((TextView)parent.getChildAt(position)).getText().toString());
To
String selectedMonth = ((TextView) view.findViewById(R.id.calendar_month)).getText().toString();
System.out.println("you have now clicked......."+selectedMonth);
Remember that according to your adapter, the getCustomView function returns an "inflated" R.layout.calendar_month_item whenever a view is requested. You then look-up the R.id.calendar_month on this view - which should contain the value of the selected month. Please check and confirm if this works. I hope it does.