CODEWITHSUNDEEP
javaandroid
Rolando Corratge Nieves
Rolando Corratge Nieves

Reputation: 1233

Fix a Java Class constructor that call Super

The code is for android but the question is related to Java I have a derived class I want to create list and pass to the super constructor while mantaining the reference in the child class

This code below is what I actualy want to do

public class AccountListAdapter extends ArrayAdapter<Account> {       
    private List<Account> cuentas;
    private Context context;    
    private AccountListStore loginstore;    
    public AccountListAdapter(Context context) {

        loginstore = new AccountListStore(context);
        try {
            cuentas = loginstore.getAccounts();
        } catch (SQLException e) {
            cuentas = new ArrayList<>();
            e.printStackTrace();
        }
        //What I wana but I know is not posible
        super(context, R.layout.acount_listadapter, cuentas);
    }

Upvotes: 2

Views: 71

Answers (2)

wero
wero

Reputation: 32980

I guess the answer of @spa already saves your problem. But there are cases where you need to construct a super constructor argument, but the super class does not give you access to that value.

You can solve this by creating a static helper method to construct the argument value and a second private constructor which you invoke from the public one:

public class AccountListAdapter extends ArrayAdapter<Account> {       
    private List<Account> cuentas;
    private Context context;    

    private static List<Account> createCuentas(Context context)
    {
        AccountListStore loginstore = new AccountListStore(context);
        try {
            return loginstore.getAccounts();
        } catch (SQLException e) {
            e.printStackTrace();
            return new ArrayList<>();
        }
    }

    public AccountListAdapter(Context context) {
        this(context, createCuentas(context));
    }


    private AccountListAdapter(Context context, List<Account> cuentas) {
        super(context, R.layout.acount_listadapter, cuentas);
        this.cuentas = cuentas;
    }
}

Upvotes: 6

spa
spa

Reputation: 5185

Super has to be called first in a constructor. I would do sth. like this:

public class AccountListAdapter extends ArrayAdapter<Account> {       
  private List<Account> cuentas;
  private Context context;    
  private AccountListStore loginstore;    

  public AccountListAdapter(Context context) {
    super(context, R.layout.acount_listadapter, new ArrayList());
    this.loginstore = new AccountListStore(context);
    try {
        this.cuentas = loginstore.getAccounts();
    } catch (SQLException e) {
        this.cuentas = new ArrayList<>();
        e.printStackTrace();
    }
    this.addAll(cuentas);
}

The only issue with that might be that ArrayAdapter works on a copy of the list. That can mean that when you adapt cuentas it might not reflect in the backing list of the adapter.

Upvotes: 2

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