java - 如何从我的自定义适配器更新 ListView

Question

我只是想更新我的 ListView，但我不能。我不知道是什么。我做错了什么？我猜想我创建的适配器缺少一些东西来返回我可以处理的真实适配器。

Home.java(MainActivity)

    protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    setContentView(R.layout.activity_main);
    BottomNavigationView navigation = (BottomNavigationView) findViewById(R.id.navigation);
    navigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener);
    MenuItem item = navigation.getMenu().findItem(R.id.navigation_home);
    item.setCheckable(true);
    item.setChecked(true);
    BoxStore boxStore = AppMain.getBoxStore();
    equipamentoBox = boxStore.boxFor(Equipamento.class);
    lancamentoBox = boxStore.boxFor(Lancamento.class);

    loadObjects();

       ////FOCUS HERE/////------------------------------
    List<Equipamento> equipamentos = new ArrayList<>();
    EquipamentoAdapter adapter;adapter = new EquipamentoAdapter(this, equipamentos);
    listEquipamentos = (ListView) findViewById(R.id.listEquipamentos);
    listEquipamentos.setAdapter(adapter);

    registerForContextMenu(listEquipamentos);



}

EquipamentoAdapter.JAVA

public class EquipamentoAdapter extends ArrayAdapter<Equipamento> {
private final Activity context;
private final List<String> idArray = new ArrayList<String>();
private final List<String> qtdArray = new ArrayList<String>();
private final ArrayList<String> nomeArray = new ArrayList<String>();
private List<Equipamento> equipamentos = new ArrayList<>();

public EquipamentoAdapter(Activity context, List<Equipamento> equipamentos) {
    super(context, R.layout.listview_row, equipamentos);
    for (Iterator iterator = equipamentos.iterator(); iterator.hasNext(); ) {
        Equipamento equipamento = (Equipamento) iterator.next();
        this.idArray.add(Integer.toString((int)equipamento.getId()));
        this.qtdArray.add(Integer.toString(equipamento.getQuantidade()));
        this.nomeArray.add(equipamento.getNome());
    }
    this.context = context;
    this.equipamentos = equipamentos;
}

public void callDialogTransaction(Equipamento equipamento) {
    AlertDialog.Builder mBuilder = new AlertDialog.Builder(getContext());
    LayoutInflater inflater = (LayoutInflater) context.getSystemService( Context.LAYOUT_INFLATER_SERVICE );

    View mView = inflater.inflate(R.layout.dialog_lancamento,null);
    TextView title = (TextView) mView.findViewById(R.id.txtTitle);
    final EditText quantidade = (EditText) mView.findViewById(R.id.edtQtd);
    final EditText Observacao = (EditText) mView.findViewById(R.id.edtObs);
    Button addTransaction = (Button) mView.findViewById(R.id.btnAddTranD);
    title.setText(equipamento.getNome());

    addTransaction.setOnClickListener(new View.OnClickListener(){
        @Override
        public void onClick(View view) {
            if(!quantidade.getText().toString().isEmpty()){
                Toast.makeText(getContext(), "Success!", Toast.LENGTH_SHORT).show();
            } else {
                Toast.makeText(getContext(), "Erro. Fill everything.", Toast.LENGTH_SHORT).show();
            }
        }
    });

    mBuilder.setView(mView);
    AlertDialog dialog = mBuilder.create();
    dialog.show();
}

public View getView(final int position, View view, ViewGroup parent) {
    LayoutInflater inflater = context.getLayoutInflater();
    View rowView = inflater.inflate(R.layout.listview_row,null,true);

    //this code gets references to objects in the listview_row.xml file
    TextView txtQtd,txtName;
    txtQtd = (TextView) rowView.findViewById(R.id.txtQtd);
    txtName = (TextView) rowView.findViewById(R.id.txtName);
    final ImageButton btnAddTransaction = (ImageButton) rowView.findViewById(R.id.btnAddTransaction);

    //this code sets the values of the objects to values from the arrays
    txtQtd.setText(qtdArray.get(position));
    txtName.setText(nomeArray.get(position));

    btnAddTransaction.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Equipamento equipamento = equipamentos.get(position);
            callDialogTransaction(equipamento);
            Animation animation = new AlphaAnimation(1.0f,0.8f);
            animation.setDuration(100);
            btnAddTransaction.startAnimation(animation);
        }
    });
    return rowView;
}

}

我读到我可以尝试使用adapter.notifyDataSetChanged();但它不起作用。另外，我尝试将其添加到 EquipamentoAdapter.java 上，并在需要刷新时从 MainActivity 进行调用，但它也不起作用。我不知道为什么。一切似乎都正确。

public void refreshData(){
    this.equipamentos.clear();
    for(Equipamento equipamento : equipamentoBox.getAll()){
        this.equipamentos.add(equipamento);
    }

    notifyDataSetChanged();
}

Answer 1

我建议进行以下更改:

1. 直接从getView内的List引用equipamento对象，这样getView函数就变成了

   public View getView(final int position, View view, ViewGroup parent) {
       LayoutInflater inflater = context.getLayoutInflater();
       View rowView = inflater.inflate(R.layout.listview_row,null,true);
   
       //this code gets references to objects in the listview_row.xml file
       TextView txtQtd,txtName;
       txtQtd = (TextView) rowView.findViewById(R.id.txtQtd);
       txtName = (TextView) rowView.findViewById(R.id.txtName);
       final ImageButton btnAddTransaction = (ImageButton) rowView.findViewById(R.id.btnAddTransaction);
   
       //this code sets the values of the objects to values from the arrays
   
       Equipamento equipamento = equipamentos.get(position);
   
       txtQtd.setText(String.valueOf(equipamento.getId()));
       txtName.setText(String.valueOf(equipamento.getQuantidade()));
   
       btnAddTransaction.setOnClickListener(new View.OnClickListener() {
       @Override
       public void onClick(View view) {
           Equipamento equipamento = equipamentos.get(position);
           callDialogTransaction(equipamento);
           Animation animation = new AlphaAnimation(1.0f,0.8f);
           animation.setDuration(100);
           btnAddTransaction.startAnimation(animation);
       }
   });
       return rowView;
   

   }

2. 使用 getCount 方法设置项目计数

   公共(public) int getCount(){ 返回设备大小()；}

使用这些，调用 notifyDataSetChanged(); 应该更新列表，而无需重新初始化适配器。