I am having a list of data objects. Each data object has a resultList
of double elements which can also be null.
I want pull out this resultList
of the data object and store them seperately in a string list:
List<List<String>> ar_List = new ArrayList<List<String>>();
for (int i = 0; i < dataList.size(); i++) {
for (int j = 0; j < dataList.get(i).getResultList().size(); j++) {
ar_List.add(dataList.get(i).getResultList().get(j).toString());
}
}
However I still get an error at ar_List.add(dataList.get(i).getResultList().get(j).toString());
Any recommendations how to write the List Objects into ar_List
?
I appreciate your answers!
replace
ar_List.add(dataList.get(i).getResultList().get(j).toString());
with
ar_List.get(i).add(dataList.get(i).getResultList().get(j).toString());
Check if the data is null because calling toString()
on a null object causes a NPE. And you need to get the List<String>
and not List<List<String>>
if(dataList.get(i).getResultList().get(j) != null) {
ar_List.get(i).add(dataList.get(i).getResultList().get(j).toString());
}
In order to check for null lists either filter the parent list for null objects or change the for condition.
for(in j = 0; j < dataList.get(i).getResultList().size(); dataList.get(i).getResultList().get(j)==null?j+=2:j++)
This jumps over the next row if the next row is null. But the better would be to clean the list.
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