Question

我正在使用android中的WordList Builder应用程序。该应用程序从数据库中提取单词并显示它们。还有一个“收藏夹”选项卡，仅显示收藏夹。主页面显示所有单词，并在喜欢的单词附近显示一个星号。当用户从“收藏夹”选项卡中取消选择一个单词并移回主页面时，该星标仍会显示在未选择的收藏夹单词上。但是，从数据库中获取的数据清楚地显示了更新。然后我将log语句添加到自定义适配器的getView方法，此处项目列表仍然显示最初加载的单词列表。它没有更新。

以下是自定义适配器的代码：

public class WordListAdapter  extends ArrayAdapter<Word> {

    protected static final String LOG_TAG = WordListAdapter.class.getSimpleName();

    private ArrayList<Word> items;
    int layoutResourceId;
    private Context context;

    public WordListAdapter(Context context,int layoutResourceId,ArrayList <Word> items) {
        super(context,layoutResourceId,items);
        this.layoutResourceId = layoutResourceId;
        this.context = context;
        this.items = items;
    }

    @Override
    public int getCount() {

        return items.size();
    }

    @Override
    public long getItemId(int position) {

        return position;
    }

    @Override
    public void notifyDataSetChanged() {
        super.notifyDataSetChanged();
        Log.i("WordListAdapter" ," NotifyDataSetChanged is called items size = " + this.items.size());
    }

    public void refreshList(ArrayList<Word> items) {
        this.items.clear();
        this.items.addAll(items);
        notifyDataSetChanged();
    }

    @Override
    public View getView(int position, View convertView, ViewGroup arg2) {
        Log.i("WordListAdapter; " , " getView item size =" + this.items.size());
        Word wordListItems = this.items.get(position);

        if (convertView == null) {
            LayoutInflater inflater = (LayoutInflater) context
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = inflater.inflate(R.layout.wordlist_item, null);

        }

        TextView tvWordName = (TextView)convertView.findViewById(R.id.wordlist_word);
        tvWordName.setText(wordListItems.getWordName());
        TextView tvWordId = (TextView)convertView.findViewById(R.id.wordlist_id);
        tvWordId.setText(Integer.toString(wordListItems.getId()));
        CheckBox cbFav = (CheckBox)convertView.findViewById(R.id.checkBoxFav);
        Log.i("WordListAdapter :" , "Position= " + position + "  Word " + wordListItems);
        cbFav.setChecked(wordListItems.isFavourite());
        cbFav.setTag(position);

        return convertView;
    }
}

以下是主要活动的代码：

public class WordBuilder extends Activity {

    //private static SimpleCursorAdapter cursorAdapter = null;
    private static WordListAdapter wordListAdapter = null;
    private static ListView lv = null;
    private static WordListDBSupport dbSupport = null;
    TabBar tabbar;
    ArrayList<Word> wordList;
    Intent intent ;

    AdapterView.OnItemClickListener mOnItemClick = new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

            long viewId = view.getId();
            TextView tv = (TextView) view.findViewById(R.id.wordlist_id);
            int rowId = Integer.parseInt(tv.getText().toString());


            Log.i("RowId : ", String.format("%d", rowId));

            Bundle bundle = new Bundle();
            bundle.putInt("rowId", rowId);
            tabbar.getIntent().putExtra("rowId", rowId);
            switchTabInActivity(tabbar.WORDLISTDETAILACTIVITY_TAB);


        }
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Log.i("WordBuilder ", " onCreate() ");
        setContentView(R.layout.activity_main);

        intent = getIntent();

        tabbar = (TabBar) this.getParent();


        dbSupport = new WordListDBSupport(this);
        lv = (ListView) findViewById(R.id.wordlist);

        //If getting tab 3, only the favourites
        wordList = new ArrayList<Word>();

        wordListAdapter = new WordListAdapter(this,R.id.wordlist, wordList);
        lv.setAdapter(wordListAdapter);

        lv.setOnItemClickListener(mOnItemClick);


    }

    public void switchTabInActivity(int indexTabToSwitchTo){
        tabbar.switchTab(indexTabToSwitchTo);
    }

    public void onResume() {
        super.onResume();
        Log.i("WordBuilder ", " onResume() ");
        updateCursorAdapter();
    }


    public void updateCursorAdapter() {
        //Query to get the updated list
        wordList.clear();
        Log.i("WordBuilder ", " updateCursorAdapter() wordList size =  " + wordList.size());
        wordList = dbSupport.getAllWords(intent.getIntExtra("isfavourite",0));
        Log.i("WordBuilder", "wordlist size after = " +wordList.size() );

        wordListAdapter.refreshList(wordList);
    }

    public void saveFavouritesHandler(View view) {

        //To be called on check or uncheck of the checkbox
        int position = (Integer)view.getTag();
        CheckBox cbFav = (CheckBox)view;
        Word wordToUpdate = wordList.get(position);
        int rowId = wordToUpdate.getId();
        Log.i("RowId isFav: ", String.format("%d ", rowId) + " isfav " + cbFav.isChecked() + " wordname= " + wordToUpdate.getWordName() + " Position = " + position);
        if (cbFav.isChecked()) {
            //save the selection in the database
            dbSupport.updateFavourite(rowId,1);
        } else {
            dbSupport.updateFavourite(rowId,0);
            Log.i("WordBuilder :" , " Position bring removed =" + position );
            if(intent.getIntExtra("isfavourite",0) == 1) {
                wordList.remove(position);
            }
        }
        updateCursorAdapter();
    }



}

我从收藏夹列表中移除了战斗并更新了数据库。然而，当我回到列出所有单词的主标签时，战斗仍被列为最爱。

Answer 1

在yiu添加或删除fav图标时，您是否正在更新ListView适配器。如果它们是两个不同的活动，你必须在onResume of mainactivity中更新aapter

Answer 2

尝试调用adapter.notifyDataSetChanged（）。当你想要刷新列表时。希望它有所帮助

来自自定义适配器的getView不更新列表项

2 个答案: