How to convert from Array<String> to String[] in Java

Question

I have to get a part of my content provider query in a String[] format. Currently I use:

        String[] selectionArgs = {"",""};
    selectionArgs[0] = Integer.toString(routeScheduleID);
    selectionArgs[1] = runDate.toString();

But in this case I have an unknown number of elements.

How can I change the number at runtime (or use something like an Array and convert back to String[]. Is this possible?

Yes, it's possible to convert between lists and arrays; check Arrays.asList and the List API. — Dave Newton
– Dave Newton, Commented Jun 27, 2012 at 11:16

JB Nizet · Accepted Answer · 2012-06-27 11:20:55Z

3

You can use List<String> to get your data and then get the array out of it:

List<String> lst = new ArrayList<String>();
lst.add(Integer.toString(routeScheduleID);
lst.add(runDate.toString());
lst.add(...);
...

String[] selectionArgs = lst.toArray(new String[lst.size()]);

edited Jun 27, 2012 at 11:20

JB Nizet

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answered Jun 27, 2012 at 11:16

Aleks G

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Pramod Kumar · Accepted Answer · 2012-06-27 11:16:44Z

2

You can use List for this. A List of Strings like this - List<String> str = new ArrayList<String>();

answered Jun 27, 2012 at 11:16

Pramod Kumar

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Comments

assylias · Accepted Answer · 2012-06-27 11:16:10Z

1

You can use a list to populate the data then convert the list into an array:

List<String> list = new ArrayList<String>();
list.add(item1);
list.add(item2);
...

String[] array = list.toArray(new String[0]);

answered Jun 27, 2012 at 11:16

assylias

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JB Nizet · Accepted Answer · 2012-06-27 11:18:31Z

1

List<String> selectionArgs = new ArrayList<String>();

selectionArgs.add(Integer.toString(routeScheduleID));
selectionArgs.add(runDate.toString());
selectionArgs.add(...).
 ...........

String[] array= selectionArgs.toArray(new String[selectionArgs.size()]);

edited Jun 27, 2012 at 11:18

JB Nizet

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answered Jun 27, 2012 at 11:17

Ahmad

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Sandeep Nair · Accepted Answer · 2012-06-27 11:19:51Z

1

List<String> selectionArgsList = new ArrayList<String>();
selectionArgsList.add("string1");
selectionArgsList.add("string2");

String[] selectionArgs = new String[selectionArgsList.length];
selectionArgsList.toArray(selectionArgs);

answered Jun 27, 2012 at 11:19

Sandeep Nair

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