Combine Multiple string-array from array.xml to one single List

Question

I have some string-array defined in the array.xml, and want to combine them in to a single List. I have try like this:

List<String> name_list;
name_list = Arrays.asList(getResources().getStringArray(R.array.name1));
name_list.addAll(Arrays.asList(getResources().getStringArray(R.array.name2)));

But error Caused by: java.lang.UnsupportedOperationException

array.xml

<string-array name="name1">
    <item>Peter</item>
    <item>Phooenix</item>
    <item>Ebele</item>
    <item>Alice</item>
</string-array>

<string-array name="name2">
    <item>Olivia</item>
    <item>Tai</item>
</string-array>

CRC · Accepted Answer · 2015-09-12 19:14:36Z

1

When you look at the Javadoc of Arrays you can see that the List returned by Arrays.asList(...) is only a Bridge to use an Array as a List and therefore is fixed size.

To solve your problem you can use something like this:

List<String> name_list = new ArrayList<>();
name_list.addAll(Arrays.asList(getResources().getStringArray(R.array.name1)));
name_list.addAll(Arrays.asList(getResources().getStringArray(R.array.name2)));

answered Sep 12, 2015 at 19:14

CRC

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2 Comments

Skyline Over a year ago

But doing like this will become java.lang.NullPointerException

Andreas Over a year ago

@MayWong The only way you'd get NPE with that code is if getResources() or getStringArray() return null, and you haven't included the code for either, so we can't help with that. If you need help with that, ask a new question, because this question has been answered.

Greg · Accepted Answer · 2015-09-12 19:10:09Z

0

Read the javadocs on Arrays.asList:

Returns a fixed-size list backed by the specified array.

So you're not allowed to call addAll in the second line of your code. Instead, you need to create your own List, and use addAll for both arrays on your own list.

answered Sep 12, 2015 at 19:10

Greg

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2 Comments

Skyline Over a year ago

Do you have any other ways to do this?

Raman Shrivastava Over a year ago

Other way could be, changing 2nd line to - name_list = new ArrayList<String>(Arrays.asList(getResources().getStringArray(R.array.name1)));

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