以编程方式创建碎片

Question

我正在尝试创建像Fragment Factory这样的代码：

首先，我的活动onCreate方法调用“criarDashboard”方法，该方法负责创建包含仪表板的新片段..

public class DashboardActivity extends FragmentActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Prancha prancha = criarPrancha();

        getSupportFragmentManager()
        .beginTransaction()
        .add(android.R.id.content, FragmentFactory.criarDashboard(this, prancha, false, false))
        .commit();


    }

    public Prancha criarPrancha(){
        byte[] img = new byte[0];

        Item i1 = new ItemExpansivel("Eu quero", img, this);
        Item i2 = new ItemExpansivel("Eu estou", img, this);

        List<Item> itens = new ArrayList<Item>();
        itens.add(i1);
        itens.add(i2);

        Prancha prancha = new Prancha(itens);

        return prancha;
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.dashboard, menu);
        return true;
    }
}

这是FragmentFactory类：

public class FragmentFactory {

    public static DashboardFragment criarDashboard(Activity context, Prancha prancha, boolean voltar, boolean proximo) {
        DashboardFragment dashboardFragment = new DashboardFragment();
        List<Item> itensHabilitados = separarItensHabilitados(prancha.getItens());
        List<List<Item>> matrizItens = ordernarItems(itensHabilitados, voltar, proximo);
        adicionarItemsLayour(matrizItens, dashboardFragment);

        return dashboardFragment;
    }

    private static List<Item> separarItensHabilitados(List<Item> itens) {
        List<Item> itensHabilitados = new ArrayList<Item>();
        for(Item item : itens) {
            if(item.isHabilitado()) {
                itensHabilitados.add(item);
            }
        }
        return itensHabilitados;
    }

    private static void adicionarItensNavegacao(final Activity context, boolean voltar, boolean proximo) {
        if(voltar) {
            Button btnBVoltar = new Button(context);
            btnBVoltar.setText(R.string.voltar);
            btnBVoltar.setOnClickListener(new View.OnClickListener() {

                @Override
                public void onClick(View v) {
                    context.onBackPressed();
                }
            });
        }

        if(proximo) {
            Button btnBVoltar = new Button(context);
            btnBVoltar.setText(R.string.proximo);
        }
    }

    @SuppressWarnings("finally")
    private static List<List<Item>> ordernarItems(List<Item> itens, boolean voltar, boolean proximo) {
        int itensLayoutInferior = (voltar ? 1:0) + (proximo ? 1:0);
        int i = 0;

        List<Item> arraySuperior = new ArrayList<Item>();
        List<Item> arrayInferior = new ArrayList<Item>();

        try {
            while (i < itensLayoutInferior) {
                arraySuperior.add(itens.get(0));
                itens.remove(0);
            }

            boolean inserirNoLayoutSuperior = true;

            while (!itens.isEmpty()) {
                if(inserirNoLayoutSuperior) {
                    arraySuperior.add(itens.get(0));
                } else {
                    arrayInferior.add(itens.get(0));
                }
                itens.remove(0);
                trocarValor(inserirNoLayoutSuperior);
            }

        } catch (ArrayIndexOutOfBoundsException e) {
            e.printStackTrace();
        } finally {
            List<List<Item>> matriz = new ArrayList<List<Item>>();
            matriz.add(arraySuperior);
            matriz.add(arraySuperior);
            return matriz;
        }
    }

    private static void trocarValor(boolean b) {
        if(b) {
            b = false;
        } else {
            b = true;
        }
    }

    private static void adicionarItemsLayour(List<List<Item>> itens, DashboardFragment dashboardFragment) {
        LinearLayout layoutSuperior = 
                (LinearLayout) dashboardFragment.getView().findViewById(R.id.linearLayoutSuperior);
        LinearLayout layoutInferior = 
                (LinearLayout) dashboardFragment.getView().findViewById(R.id.linearLayoutInferior);

        for (Item item : itens.get(0)) {
            layoutSuperior.addView(item);
        }
        for (Item item : itens.get(1)) {
            layoutInferior.addView(item);
        }
    }
 }

adicionarItemsLayout方法中出现错误，它是dashboardFragment的getView方法中的一个简单空指针。 问题是..在这种情况下我应该如何实例化一个新的片段..