android - ListView clickEvent 选择了错误的数据库行 ID - 帮助!

Question

我有一个 ListView，可将数据从数据库填充到复杂的 ListView 中。数据库的“gotoURL”列中的字符串是使用 putExtra Intent 将链接加载到 WebView 的 URL。当我单击 ListItem 转到下一个 Activity 时，我的方法获取了正确的字符串数据，但它从错误的数据库行中提取了字符串。根据我的“log.i(...);”指示在 DDMS 中，选择了正确的 ID 行，但列中的字符串是从第一行 ID 中提取的，而不是从选定的行 ID 中提取的(？？？) - 它在任何选定的 ListItem 上执行此操作。

我不知道如何编写才能正常运行。请帮助示例代码。谢谢。

我的 Activity :

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    setContentView(R.layout.list_view2);

    activityTitle = (TextView) findViewById(R.id.titleBarTitle);
    activityTitle.setText("ADVISORY CIRCULATORS");

    displayResultList();

    final ListView lv = getListView();
    lv.setTextFilterEnabled(true);
    lv.setClickable(true);

    lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {

        @Override
        public void onItemClick(AdapterView<?> a, View v, int pos,
                long id) {

            String url = "";
            lv.getItemIdAtPosition(pos);
            TextView tv = (TextView) lv.findViewById(R.id.dummy);
            url = (String) tv.getTag();

            LLog.i("tag", "ID:" + id + "URL: " + url + " selected");
            Intent i = new Intent(List_AC.this, DocView.class);
            i.putExtra("url", url);
            startActivity(i);
        }
    });
}

private void displayResultList() {

    if (android.os.Environment.getExternalStorageState().equals(
            android.os.Environment.MEDIA_MOUNTED)) {
        extStorageDirectory = Environment.getExternalStorageDirectory()
                .toString();

        File dbfile = new File(extStorageDirectory
                + "/Aero-Technologies/flyDroid/dB/flyDroid.db");

        SQLiteDatabase db = SQLiteDatabase.openOrCreateDatabase(dbfile,
                null);

        Cursor databaseCursor = db.rawQuery(
                "SELECT * FROM AC_list ORDER BY `label` ASC", null);

        Adapter_AC databaseListAdapter = new Adapter_AC(this,
                R.layout.list_item, databaseCursor, new String[] { "label",
                        "title", "description", "gotoURL" }, new int[] {
                        R.id.label, R.id.listTitle, R.id.caption,
                        R.id.dummy });

        databaseListAdapter.notifyDataSetChanged();
        this.setListAdapter(databaseListAdapter);

        } else if (android.os.Environment.getExternalStorageState().equals(
            android.os.Environment.MEDIA_UNMOUNTED)) {
            Log.i("tag", "SDCard is NOT writable/mounted");
            Alerts.sdCardMissing(this);
        }
    }
}

我的适配器:

public class Adapter_AC extends SimpleCursorAdapter {


static Cursor dataCursor;
private LayoutInflater mInflater;

public Adapter_AC(Context context, int layout, Cursor dataCursor,
        String[] from, int[] to) {
    super(context, layout, dataCursor, from, to);
    this.dataCursor = dataCursor;
    mInflater = LayoutInflater.from(context);
}

public View getView(int position, View convertView, ViewGroup parent) {

    ViewHolder holder;

    if (convertView == null) {
        convertView = mInflater.inflate(R.layout.list_item, null);

        holder = new ViewHolder();
        holder.text1 = (TextView) convertView.findViewById(R.id.label);
        holder.text2 = (TextView) convertView.findViewById(R.id.listTitle);
        holder.text3 = (TextView) convertView.findViewById(R.id.caption);
        holder.text4 = (TextView) convertView.findViewById(R.id.dummy);

        holder.text4.setVisibility(View.GONE);

        convertView.setTag(holder);

    } else {
        holder = (ViewHolder) convertView.getTag();
    }

    dataCursor.moveToPosition(position);

    int label_index = dataCursor.getColumnIndex("label");
    String label = dataCursor.getString(label_index);

    int title_index = dataCursor.getColumnIndex("title");
    String title = dataCursor.getString(title_index);

    int description_index = dataCursor.getColumnIndex("description");
    String description = dataCursor.getString(description_index);

    int goto_index = dataCursor.getColumnIndex("gotoURL");
    String gotoURL = dataCursor.getString(goto_index);

    holder.text1.setText(label);
    holder.text2.setText(title);
    holder.text3.setText(description);
    //holder.text4.setText(gotoURL);
    holder.text4.setTag(gotoURL);

    return convertView;
}

static class ViewHolder {
    TextView text1;
    TextView text2;
    TextView text3;
    TextView text4;
}

}

Answer 1

好的，您的 onItemClick 有一些错误(请参阅内联评论):

 lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> a, View v, int pos,
                long id) {

            String url = "";
            lv.getItemIdAtPosition(pos); //you're never storing this value, but that's not the problem


            //This "lv" is the main problem: you're asking the LISTVIEW for the TextView
            //That's why you always get the first one. You should be asking the current view (v) instead
            TextView tv = (TextView) lv.findViewById(R.id.dummy); 
            url = (String) tv.getTag();

            LLog.i("tag", "ID:" + id + "URL: " + url + " selected");
            Intent i = new Intent(List_AC.this, DocView.class);
            i.putExtra("url", url);
            startActivity(i);
        }
    });

但是，为什么您要尝试使用 holder 中的数据而不是获取 backing tiem？