Add line with empty fields in a Jtable

Question

I have a AbstractTableModel only that I do not know how to add blank lines, when pressing the add line button on my frame I want it to call a method called addLine() of my Modelotabela, someone can help me?

    public class ModeloTabela2 extends AbstractTableModel {
    private ArrayList linhas = new ArrayList();
    private String[] colunas = {"DATA", "EVOLUÇÃO"};

    public boolean isCellEditable(int linha, int coluna) {
        return true;
    }

    public ArrayList getLinhas(){
        return linhas;
    }
    public void setLinhas(ArrayList dados){
        linhas = dados;
    }
    public String[] getColunas(){
        return colunas;
    }
    public void setColunas(String[] nomes){
        colunas = nomes;
    }
    public int getColumnCount(){
        return colunas.length;
    }
    public int getRowCount(){
        return linhas.size();
    }
    public String getColumnName(int numCol){
        return colunas[numCol];
    }
    public Object getValueAt(int numLin, int numCol){
        Object[] linha = (Object[])getLinhas().get(numLin);
        return linha[numCol];
    }
    public Class<?> getColumnClass(int coluna) {
        switch(coluna){
        case 0:
            return String.class;
        case 1:
            return String.class;
        default:
            return String.class;
        }

    }
    public void addLinha(){       //Aqui eu adicionaria a linha em branco...

    }

}

Answer 1

Just add a Object empty in the method addLinha(), and inform listeners that the list has been modified, using fireTableDataChanged():

public void addLinha(){ 
    this.linhas.add(new Object[]{});
    this.fireTableDataChanged();
}

In his TableModel the method setValueAt() is not defined, and it is precisely this method that tells your model how to add new objects (rows) in your table. See the question below for a brief explanation of how to create a TableModel and use it to popular a table.

How popular a Jtable with its own Tablemodel?