Question

我正在做一个应用程序来帮助我在学校。但是，我有一个问题：当我想要listView的位置（int位置）时，它总是返回第一个位置，即使我选择第三个位置，例如。

public class TestsActivity extends ListActivity implements AdapterView.OnItemClickListener, DialogInterface.OnClickListener {
    private List<Map<String, Object>> tests;
    private AlertDialog dialogDelete;
    private int selectedTest;
    private Application dao;

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

        dao = new Application(this);

        android.app.ActionBar actionBar = getActionBar();
        actionBar.setTitle("My tests");

        actionBar.setHomeButtonEnabled(true);
        actionBar.setDisplayHomeAsUpEnabled(true);

        String[] from = {"subject", "content"};
        int[] to = {R.id.subject, R.id.content};

        SimpleAdapter adapter = new SimpleAdapter(this, listTests(), R.layout.test_list_activity, from, to);
        setListAdapter(adapter);
        getListView().setOnItemClickListener(this);

        registerForContextMenu(getListView());

        this.dialogDelete = createDialogDelete();
    }

    private List<Map<String, Object>> listTests() {

        tests = new ArrayList<Map<String, Object>>();

        List<Test> TestList = dao.listTests();

        for (Test test : TestList) {

            Map<String, Object> item = new HashMap<String, Object>();

            Long id = test.getId();
            String subject = test.getSubject();

            item.put("id", test.getId());

            item.put("subject", subject);

            test.add(item);
        }

        return tests;
    }

    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
        Map<String, Object> map = tests.get(position);

        String subject = (String) map.get("subject");
        String msg = "Test of" + subject;

        Toast.makeText(this, msg, Toast.LENGTH_SHORT).show();

        selectedTest = position;

    }

    @Override
    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.tests_context_menu, menu);
    }

    public boolean onContextItemSelected(MenuItem item) {

        Intent intent;
        String id = String.valueOf(tests.get(selectedTest).get("id"));

        switch (item.getItemId()) {

            case R.id.remove:
                dialogDelete.show();
                break;

            case R.id.edit:
                intent = new Intent(this, NewTestActivity.class);
                intent.putExtra(Constantes.TEST_ID, id);
                startActivity(intent);
                return true;
        }

        return super.onContextItemSelected(item);
    }

    @Override
    public void onClick(DialogInterface dialog, int item) {
        Intent intent;
        String id = String.valueOf(tests.get(selectedTest).get("id"));

        switch (item) {
            case DialogInterface.BUTTON_POSITIVE:
                tests.remove(selectedTest);
                dao.removeTest(id);
                getListView().invalidateViews();
                break;

            case DialogInterface.BUTTON_NEGATIVE:
                dialogDelete.dismiss();
                break;
        }
    }

    private AlertDialog createDialogDelete() {
        AlertDialog.Builder builder = new AlertDialog.Builder(this);

        builder.setMessage(R.string.confirm_delete_test);

        builder.setPositiveButton(getString(R.string.yes), (android.content.DialogInterface.OnClickListener) this);
        builder.setNegativeButton(getString(R.string.no), (android.content.DialogInterface.OnClickListener) this);

        return builder.create();
    }

    @Override
    protected void onDestroy() {
        dao.close();
        super.onDestroy();
    }
}

我该如何解决？

Answer 1

for (Test test : TestList) {

        Map<String, Object> item = new HashMap<String, Object>();

        Long id = test.getId();
        String subject = prova.getSubject();

        item.put("id", prova.getId());

        item.put("subject", subject);

        tests.add(item);
    }

尝试从

更改

test.add(item);

到

tests.add(item);

Answer 2

你有没有在你的Activity中调用listTests（）？它的私有方法是什么？

你应该在某个地方调用listTests（）。

Answer 3

也许你应该使用自定义BaseAdapter 它可以帮助你清楚地创建listview的每一个细节

private class  Simple extends BaseAdapter {
    @Override
    public int getCount() {
        return 0;
    }

    @Override
    public Object getItem(int i) {
        return i;
    }

    @Override
    public long getItemId(int i) {
        return i;
    }

    @Override
    public View getView(int i, View view, ViewGroup viewGroup)
    {
        return view;
    }
}

Answer 4

根据您的回答，以下是我的建议。

1）在 listTests （）中，更改为：

test.add(item);

TO：

tests.add(item);

原因是对象 tests 是包含对象测试的ArrayList。

2）由于代码取决于List<Test> TestList = dao.listTests();的列表dao，我想避免意外删除列表项。所以在protected void onDestroy()中，删除：

dao.close();

ListView始终返回第一个位置

4 个答案: