Question

What I’m trying to do is basically delete one position in the hashtable and then save that hashtable to a file on the user’s phone. The hashtable only has strings so no serialization is involved. The layout of the hashtable is as follows:

Key->Integer

Value->ArrayList()

In the arrayList is just string values.

The problem I have is when I delete one position in the arrayList, IF it was the last value in that arrayList that means that, That position in the hashtable has become null. And for some reason I can’t check for this case… I’ve tried various functions and none seem to work. Here is the code where I delete the value from the hashtable

    // delete the assignment from the public list
                for (int i = 0; i < allAssignments.size(); i++) {

        //Here is where I get a null pointer-vvv    
    for (int p = 0; p < allAssignments.get(i).size(); p++) {
                        if (allAssignments.get(i).get(p).getTitle().equals(title)
                                && allAssignments.get(i).get(p)
                                        .getDate_due().equals(Date)) {
                            allAssignments.get(i).remove(p);
                        }
                    }
            }

The deletion works perfectly fine if I delete positions in order like 4-3-2-1, but if I try and delete the 1st position and then try to delete the 2nd position it will give me a null pointer because it’s trying to access the 1st position first. Any suggestions?

Answer 1

ArrayList temp = allAssignments.get(i);
if(temp !null){
...
}

this checks for null.

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