Android：简单适配器的正确参数是什么？

我无法使列表视图显示其中的任何内容。它已正确创建，但项和子项均为空。我如何解决这个问题

我在适配器中使用的参数是否正确

SimpleAdapter adapter = new SimpleAdapter(this, list, android.R.layout.simple_list_item_2, keys, ids);

具有列表视图的活动：

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.results);

        ListView itemList = (ListView) findViewById(R.id.lvresults);

        //gets array from prev act
        int[] results = getIntent().getIntArrayExtra("results");

        int numberPassed = getIntent().getIntExtra("numberPassed", 0);


        ArrayList < HashMap <String, String> > list = new ArrayList < HashMap <String, String> > ();


        // loop to give list view
        for (int i = 1; i <= 12; ++i)
        {
            int userAnswer = results[i - 1];

            int expectedAnswer = numberPassed * i;

            String userString = numberPassed + "x" + i + "=" + userAnswer;

            String expectedString = "" + expectedAnswer;

            HashMap <String, String> map = new HashMap <String, String> ();

            map.put("user", userString);
            map.put("expected", expectedString);

            list.add(map);
        }


        String[] keys = {"user", "expected"};

        int[] ids = {R.id.user_answer, R.id.expected_answer};

        SimpleAdapter adapter = new SimpleAdapter(this, list, android.R.layout.simple_list_item_2, keys, ids);

        itemList.setAdapter(adapter);
    }
}

---

您正在使用android.R.layout.simple_list_item_2作为行布局。它不会有带有这些ID的字段。您应该用自己的布局id替换它。

检查您的键是否正确。