Dynamic Array - Android

Question

How to create a dynamic array in this way:

//Apenas um exemplo abaixo:

String valor0 = "1;2;3;4;5;6;7;8;9;0";
String valor1 = "1;2;3;4;5;6;7;8;9;0";
String valor2 = "1;2;3;4;5;6;7;8;9;0";

//Um array dentro de outro array, porém sem definir seu tamanho
String[][] valor = {};

//E então definir os valores do segundo [] com split também
valor[0][] = valor0.split(";");
valor[1][] = valor1.split(";");
valor[2][] = valor2.split(";");

So he would create the keys and after creating, set the values of the other array within each key with the split. The size should be with the split, because this will be dynamic, will change constantly. In cases of being just a normal array, I know that the split populates it dynamically without having to define the size, but I would like to do the same with a two-dimensional array.

The example does not work, of course, is only to show.

The array would look something like this:

array (size=3)
  0 => 
    array (size=10)
      0 => string '1' (length=1)
      1 => string '2' (length=1)
      2 => string '3' (length=1)
      3 => string '4' (length=1)
      4 => string '5' (length=1)
      5 => string '6' (length=1)
      6 => string '7' (length=1)
      7 => string '8' (length=1)
      8 => string '9' (length=1)
      9 => string '0' (length=1)
  1 => 
    array (size=10)
      0 => string '1' (length=1)
      1 => string '2' (length=1)
      2 => string '3' (length=1)
      3 => string '4' (length=1)
      4 => string '5' (length=1)
      5 => string '6' (length=1)
      6 => string '7' (length=1)
      7 => string '8' (length=1)
      8 => string '9' (length=1)
      9 => string '0' (length=1)
  2 => 
    array (size=10)
      0 => string '1' (length=1)
      1 => string '2' (length=1)
      2 => string '3' (length=1)
      3 => string '4' (length=1)
      4 => string '5' (length=1)
      5 => string '6' (length=1)
      6 => string '7' (length=1)
      7 => string '8' (length=1)
      8 => string '9' (length=1)
      9 => string '0' (length=1)

I did this example in php

Answer 1

If you need the array to be dynamic use an List, such as a ArrayList.

According to the example you gave only the lines would need to be dynamic, in which case you could define the array as:

ArrayList<String[]> valor

This allows you to add as many array Strings you want. The arrays themselves added don’t have to be the same size so they can pick up the size that comes from the split. The addition is made with the method add instead of by the index.

Example:

String valor0 = "1;2;3;4;5;6;7;8;9;0";
String valor1 = "1;2;3;4;5;6;7;8;9;0";
String valor2 = "1;2;3;4;5;6;7;8;9;0";

ArrayList<String[]> valor = new ArrayList<>();

valor.add(valor0.split(";")); //adiciona cada linha com add
valor.add(valor1.split(";"));
valor.add(valor2.split(";"));

Now to use just two for one for rows and one for columns:

for (String[] linha : valor){ //percorrer cada linha
    for (String item : linha){ //percorrer cada item/coluna na linha
        System.out.print(item + " ");
    }
    System.out.println();
}

See this example in Ideone

It is worth remembering that with a ArrayList to access a position you must use the method get. So if you want later to access the second value of the first line would have to do:

String segundoPrimeiraLinha = valor.get(0)[1];
//------------------------------------^

Where in a String[][] would:

String segundoPrimeiraLinha = valor[0][1];

Answer 2

Just to show that this is possible with a multidimensional array, as AP requests.

String valor0 = "1;2;3;4;5;6;7;8;9;0";
String valor1 = "1;2;3;4;5;6;7;8;9;0";
String valor2 = "1;2;3;4;5;6;7;8;9;0";

String[][] valor = new String[3][];

valor[0] = valor0.split(";");
valor[1] = valor1.split(";");
valor[2] = valor2.split(";");

for(String[] linha : valor) {           
    for (String item : linha) {     
        System.out.print(item + " ");
    }
    System.out.println();
}

See on Ideone.

Answer 3

Using List you can create them dynamically follows the code:

List<List<String>> valor = new ArrayList<ArrayList<String>>();
valor.add(Arrays.asList(valor0.split(";"));
valor.add(Arrays.asList(valor1.split(";"));
valor.add(Arrays.asList(valor2.split(";"));