array required, but ArrayList<String> found

Question

I have a ruby backround and im new to java i wrote a basic programm but somehow i get a error i cant fix! My code:

import java.util.ArrayList;

public class Music {

    private ArrayList<String> files;


    public static void main(String args[]){

        Music a = new Music();
        a.addFile("Chasen Paper");
        a.addFile("Mama");
        a.addFile("Hell Yes");
        a.removeFile("Hell Yes");
    }
    public Music(){
      files = new ArrayList<String>();
    }

    public void addFile(String filename){
        files.add(filename);
    }

    public void returnFiles(){
        for(int i = 0; files.size() <= i; i++){
            System.out.println( i + ". Ist: " + files[i]);
        }

    }

    public void removeFile(String filename){
        System.out.println("Vorher gab es " + files.size() + " Dateien");
        files.remove(filename);
        System.out.println("Jetzt gibt es " + files.size() + " Dateien");
    }
}

When i try to compile it i get somehow this error: What did i wrong? Thanks!

Music.java:26: error: array required, but ArrayList<String> found
            System.out.println( i + ". Ist: " + files[i]);

Answer 1

You need to use the get() method to get the element at a particular index from an ArrayList. You can't use [] to get the element at a particular index, in an arraylist. Its possible only for arrays and your files is not an array, but an ArrayList.

System.out.println( i + ". Ist: " + files.get(i));

Also, the condition in your for loop is a bit off. files.size() <= i is false, and therefore, it doesn't enter the for loop at all.

Change it to something like this.

for(int i = 0; i < files.size() ; i++){