Java ArrayList values are being reset when new values are being added on

Question

So every time I run the method test my String array is added to my ArrayList and it will print out the lyricLineInfo[4] value, but when the method test is ran again the array will be added on to the ArrayList but it will also replace all of the other ArrayList values with the new array. So when lyricLineInfo[4] is printed again it prints the new value instead of the old value like it's suppose to. I'm not sure why it's doing this can anyone help? Here is my code:

private String[] lyricLineInfo = new String[5];
private ArrayList<String[]> lyricLineNumber = new ArrayList<String[]>();

public void test() {
    lyricLineNumber.add(getInfo());
    System.out.println(lyricLineNumber.get(0)[4])
}

public String[] getInfo() {
    if (chckbxLeadSinger.isSelected()) {
        lyricLineInfo[0] = "true";
    } else {
        lyricLineInfo[0] = "false";
    }
    if (chckbxBackupSinger.isSelected()) {
        lyricLineInfo[1] = "true";
    } else {
        lyricLineInfo[1] = "false";
    }
    lyricLineInfo[2] = fieldStartTime.getText();
    lyricLineInfo[3] = fieldEndTime.getText();
    lyricLineInfo[4] = fieldLyrics.getText();
    return lyricLineInfo;
}

Don Roby · Accepted Answer · 2011-12-27 23:19:13Z

6

You're only creating one lyricLineInfo. It shouldn't be a field but a local variable created inside the getInfo() method.

That is to say, remove the line

private String[] lyricLineInfo = new String[5];

and add

String[] lyricLineInfo = new String[5];

as the first line in your getInfo() method.

answered Dec 27, 2011 at 23:19

Don Roby

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2 Comments

MByD Over a year ago

+1 as this is correct AFAIK, but it would be better if you elaborate.

Don Roby Over a year ago

@Binyamin Sharet - I had saved a partial edit and was elaborating a bit as you wrote this.

Jon Story · Accepted Answer · 2011-12-27 23:28:34Z

1

You're adding a POINTER to the array to the array list, not a COPY of it. So when you change the array, it changes what you appear to have in the array list.

Try

public void test()
{
    String[] temp = new String[5];
    temp = getInfo();
    lyricLineNumber.add(temp);
}

answered Dec 27, 2011 at 23:28

Jon Story

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