RecyclerView 不更新

Question

我的 MainActivity 有一个 recyclerview 将接收产品。在 MainActivity 的 floatActionButton 中，我调用 AddActivity ，它具有添加产品的字段，包括一个回收器，我在其中插入输入以构成价格。问题正是在 AddActivity recyclerView

我有一个简单的 recyclerView 和下面的适配器，我在保存到数据库之前在其中执行 CRUD，除了更新之外一切正常，我通过适配器更新项目，但列表中的视图不更新数据。如果您单击同一项目再次对其进行编辑，则会显示已更新的值，而不是列表中显示的值。

在我的适配器下方：

public class InsumoAdapter extends RecyclerView.Adapter<InsumoAdapter.InsumoViewHolder>{

   
    private final Context context;
    private List<Insumo> insumos;


    public InsumoAdapter(Context context, List<Insumo> insumos) {
        this.context = context;
        this.insumos = insumos;
    }

    @Override
    public InsumoAdapter.InsumoViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
        View view = LayoutInflater.from(context).inflate(R.layout.card_teste, viewGroup, false);
        InsumoAdapter.InsumoViewHolder holder = new InsumoAdapter.InsumoViewHolder(view);
        return holder;
    }

    public static class InsumoViewHolder extends RecyclerView.ViewHolder{
        public TextView tNome, tVlrCusto;
        ImageButton btnDelete;
        CardView cardView;
        public InsumoViewHolder(View view){
            super(view);
            tNome = (TextView) view.findViewById(R.id.txtNomeProd);
            tVlrCusto = (TextView) view.findViewById(R.id.txtValorProd);
            btnDelete = (ImageButton) view.findViewById(R.id.imgBtnDel);
            cardView = (CardView) view.findViewById(R.id.cardProduto);
        }
    }

    @Override
    public void onBindViewHolder(final InsumoViewHolder holder, final int position) {
        if(insumos.size() != 0){
            final Insumo p = insumos.get(position);
            holder.tNome.setText(p.getNomeInsumo());
            holder.tVlrCusto.setText(p.getValor().toString());

            holder.cardView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Toast.makeText(context, "Clicou no Card para Editar na posição "+position,Toast.LENGTH_SHORT).show();
                    Bundle bundle = new Bundle();
                    //bundle.putString("nome", p.getNomeInsumo());
                    //bundle.putDouble("valor", p.getValor());
                    bundle.putInt("position", position);
                    Intent intent = new Intent(context, UpdateActivity.class);
                    intent.putExtras(bundle);
                    context.startActivity(intent);
                    //update(p, position);
                }
            });

            holder.btnDelete.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Toast.makeText(context, "Clicou no Card para Excluir na posição "+position,Toast.LENGTH_SHORT).show();
                    delete(position);
                }
            });
        }
    }

    @Override
    public int getItemCount() {
        return this.insumos != null ? this.insumos.size() : 0;
    }


    private void excluirInsumo(Context context, final int i){
        String titulo = "Excluir";
        String msg = "Deseja excluir este item?";
        AlertDialog alertDialog = new AlertDialog.Builder(context).create();
        alertDialog.setTitle(titulo);
        alertDialog.setMessage(msg);
        alertDialog.setButton(AlertDialog.BUTTON_POSITIVE, "Sim",
                new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        //deleta("Pproduto",produtos.get(i).get_id());
                        AddActivity addActivity = new AddActivity();
                        //addActivity.deleta(i);

                        dialog.dismiss();
                    }
                });
        alertDialog.setButton(AlertDialog.BUTTON_NEGATIVE, "Não",
                new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.dismiss();
                    }
                });
        alertDialog.show();
    }

    private void delete(int position){
        insumos.remove(position);
        notifyItemRemoved(position);
    }

    public void update(Insumo insumo, int position){
        insumos.set(position, insumo);
        //notifyItemChanged(position);
        notifyDataSetChanged();
    }

    public void insere(Insumo insumo){
        insumos.add(insumo);
        notifyDataSetChanged();
    }

这就像不回到 onBindViewHolder 来更新数据。有人可以给我一盏灯吗？如果你需要一些东西，但你找不到任何方法。

编辑-----

添加活动

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_add);

        edtNome = (TextInputEditText) findViewById(R.id.edtNome);
        valorCusto = (TextView) findViewById(R.id.txtValorCustoAdd);
        valorVenda = (TextView) findViewById(R.id.txtValorVendaAdd);
        valorPerc = (TextView) findViewById(R.id.txtValorPercAdd);
        addItem = (FloatingActionButton) findViewById(R.id.fltBtnAddItem);
        addFoto = (FloatingActionButton) findViewById(R.id.fltBtnAddFoto);
        salvar = (FloatingActionButton) findViewById(R.id.fltBtnSalvar);
        imgFoto = (ImageView) findViewById(R.id.imgFoto);
        recyclerView = (RecyclerView) findViewById(R.id.recy);

        edtNome.setTextIsSelectable(true);

        valorCusto.setText(valor.toString());
        valorPerc.setText("0");

        recyclerView.setLayoutManager(new LinearLayoutManager(getApplicationContext()));
        recyclerView.setItemAnimator(new DefaultItemAnimator());
        recyclerView.setHasFixedSize(true);

        InsumoAdapter insumoAdapter = new InsumoAdapter(getApplicationContext(), insumos);

        recyclerView.setAdapter(insumoAdapter);
        insumoAdapter.notifyDataSetChanged();

        addItem.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(getApplication(), InsertActivity.class);
                startActivity(intent);
            }
        });

        salvar.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Produto produto = new Produto();
                produto.setpNome(edtNome.getText().toString());
                produto.setpValorCusto(somaValor(insumos));
                if(foto == 0){
                    produto.setPfoto(R.drawable.noimage);
                }else{
                    produto.setPfoto(foto);
                }
            }
        });
    }

insumo 的插入活动

update.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                insumo = new Insumo();
                insumo.setNomeInsumo(nome.getText().toString());
                Log.d(TAG, getClass()+" insumo.getNome = "+insumo.getNomeInsumo());
                insumo.setValor(Double.parseDouble(valor.getText().toString()));
                Log.d(TAG, getClass()+" insumo.getValor = "+insumo.getValor());
                AddActivity addActivity = new AddActivity();
                //addActivity.update(insumo, pos);
                InsumoAdapter insumoAdapter = new InsumoAdapter(getBaseContext(), addActivity.lista());
                insumoAdapter.update(insumo, pos);
                insumoAdapter.notifyDataSetChanged();
                finish();
            }
        });

主要活动

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        recyclerView = (RecyclerView) findViewById(R.id.recyclerTeste);
        FloatingActionButton btn = (FloatingActionButton) findViewById(R.id.fltBtnAdd);

        recyclerView.setLayoutManager(new LinearLayoutManager(getApplicationContext()));
        recyclerView.setItemAnimator(new DefaultItemAnimator());
        recyclerView.setHasFixedSize(true);

        ProdutoAdapter produtoAdapter = new ProdutoAdapter(getBaseContext(), produtos);

        recyclerView.setAdapter(produtoAdapter);
        produtoAdapter.notifyDataSetChanged();


        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(MainActivity.this, AddActivity.class);
                startActivity(intent);
            }
        });

Answer 1

问题是；您正在创建一个新的适配器实例，而不是使用附加到您的recyclerView 的适配器。请使用附加到您的 recyclerView 的相同适配器实例。

在您的 recyclerView 实例化的 Activity 中，使用成员引用来包含您的引用。即mInsumoAdapter

然后，当您创建第一个适配器实例并将其附加到您的 recyclerView 时，将其分配给 mInsumoAdapter。

最后使用相同的引用来调用你的update 方法。

mInsumoAdapter.update(insumo, pos);

为了在活动和服务之间共享引用，您可以像这样创建一个公共共享类：

public class ReferenceUtil {
    private static InsumoAdapter insumoAdapter;

    public static InsumoAdapter getMainAdapter(){
        return insumoAdapter;
    }

    public static void setMainAdapter(InsumoAdapter adapter) {
        insumoAdapter = adapter;
    }
}

然后在您单击 FAB 时使用 ReferenceUtil.setMainAdapter(adapter);，并在您的下一个活动中使用 ReferenceUtil.getMainAdapter(); 获取您附加的参考并更新该参考以供您的 recyclerView 在运行时更新。

当您返回之前的活动时，请记住将 ReferenceUtil 中的静态 insumoAdapter 设置为 null，因为这可能会导致您的应用程序发生内存泄漏。

Answer 2

不用创建新的适配器，只需使用当前的适配器实例并将其用于更新和 notifyDataSetChanged。

public InsumoAdapter insumoAdapter;

// Inside onCreate
@Override
protected void onCreate(Bundle savedInstanceState) {
    ....
    insumoAdapter = new InsumoAdapter(getApplicationContext(), insumos);
    ....
}

// Inside Update onClick
update.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
    ....
    insumoAdapter.update(insumo, pos)
    insumoAdapter.notifyDataSetChanged()
}

Answer 3

尝试在您将列表传递给适配器的活动中使用 notifyDataSetChnaged() ，或者您可以在更新它之后执行此操作。像这样的，

RecyclerView.setAdapter(this,list);
notifyDataSetChanged();

或

InsumoAdapter.update(list,pos);
notifyDataSetChanged();

您可以尝试将这种方式用于所有 CRUD 操作。