Android notifyDataSetChanged（）不起作用

Question

我正在研究 ArrayAdapter 和 ListView。我有一个活动 A 和活动 B。 Activity A 启动一个 Activity B (startActivityForResult())，当 Activity B 完成时，它会将结果返回给 Activity A 。

活动A：

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.home);
    listViewPrayerList = (ListView) findViewById(R.id.listView_prayerlist);
    prayerList = new ArrayList<PrayerSetting>();
    if (getIntent().hasExtra(Utils.PRAYER_LIST)) {
        prayerList.clear();
        prayerList.addAll((ArrayList<PrayerSetting>) getIntent()
                .getSerializableExtra(Utils.PRAYER_LIST));
        pAdapter = new PrayerAdapter(this, R.layout.prayer_list_item,
                prayerList);
  }
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if (data != null && data.hasExtra(Utils.SETTINGS)) {
        PrayerSetting p = (PrayerSetting) data
                .getSerializableExtra(Utils.SETTINGS);
        prayerList.set(itemClickedPosition, p);
        pAdapter.notifyDataSetChanged(); // UI/List doesn't change
    }
}

我不明白我做错了什么！我尝试了很多解决方案，但仍然没有得到它。

1. Stackoverflow Question 1
2. Stackoverflow Question 2
3. Stackoverflow Question 3
4. Blogspot link
5. Stackoverflow Question 4

我明白这是一个基本问题。提前致谢。

Answer 1

尝试移动

pAdapter = new PrayerAdapter(this, R.layout.prayer_list_item,
    prayerList);

onCreate 中的 if 语句之前