在此应用程序中，数据被插入到编辑文本中。然后，当您按 Enter 键时，应用程序会检查插入的数据是否存在于文本文件中。如果是，则将文本文件中的信息拆分并添加到 ListView 中。
主要操作有效，但 ListView 未填充数据。
我尝试将 listView.setAdapter(adapter) 从 onCreate 方法更改为 enterKey 监听器内部。当我这样做时， ListView 被填充，但始终具有相同的数据。
public class Main4Activity extends AppCompatActivity{
private static final String TAG = "Main4Activity";
ListView listView;
Boolean scanOpenStatus;
EditText editText4;
SimpleAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main4);
editText4 = (EditText) findViewById(R.id.editTextCodigo);
listView = findViewById(R.id.listViewXML);
final List<HashMap<String, String>> listagem = new ArrayList<>();
adapter = new SimpleAdapter(this, listagem, R.layout.layoutlist, new String[] {"Principal", "Sub"}, new int[] {R.id.textViewListViewMain, R.id.textViewListViewSub});
final HashMap<String, String> dados = new HashMap<>();
listView.setAdapter(adapter);
listView.setFocusable(false);
listView.setItemsCanFocus(false);
editText4.setOnKeyListener(new View.OnKeyListener() {
@Override
public boolean onKey(View v, int keyCode, KeyEvent event) {
boolean check = false;
if ((keyCode == KeyEvent.KEYCODE_ENTER) &&
(event.getAction() == KeyEvent.ACTION_DOWN)) {
String codigoLido = editText4.getText().toString().trim();
editText4.setText("");
if (!codigoLido.equals("")) {
try {
File caminhoTxt = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS) + "/lookupscangs1.txt");
if (caminhoTxt.exists()) {
try {
String line;
FileReader fileReader = new FileReader(caminhoTxt);
BufferedReader buffer = new BufferedReader(fileReader);
while ((line = buffer.readLine()) != null) {
String[] codDesc = line.split(";");
String codigo = codDesc[0];
String descricao = codDesc[1];
if (codigo.equals(codigoLido)) {
dados.put("Principal", codigoLido);
dados.put("Sub", descricao);
listagem.add(dados);
check = true;
break;
}
}
dados.put("Principal", codigoLido);
dados.put("Sub", "Código Não Cadastrado!");
listagem.add(dados);
check = true;
}
catch (Exception e) {
Toast.makeText(getApplicationContext(), "Catch 01: " + (CharSequence) e, Toast.LENGTH_SHORT).show();
}
}
} catch(Exception e){
Toast.makeText(getApplicationContext(), "Catch 02: " + e, Toast.LENGTH_SHORT).show();
}
}
else {
Toast.makeText(getApplicationContext(), "Insira um Código!", Toast.LENGTH_SHORT).show();
check = false;
}
}
editText4.requestFocus();
return check;
}
});
}
}
最佳答案
您是否尝试过手动更新显示
adapter.notifyDataSetChanged();
关于java - ListView未填充数据，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/57790747/