android:listview:获取项目点击的光标值

Question

我用列创建了一个数据库和表(类别)(_id,title,...)我想从db读取类别并将类别列表显示为列表视图.

这是y代码:

   public class MainActivity extends listActivity{

    private ArrayAdapter arrayAdapter;
    ArrayList results = new ArrayList();
    ListView catlist;
    Cursor cur;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        catlist = getListView();

        int parentid = getIntent().getIntExtra("catid", 0);
        openAndQueryDatabase(parentid);

        displayCatListView();




    }

    private void displayCatListView() {

        setListAdapter(new ArrayAdapter<String>(this,
                android.R.layout.simple_list_item_1, results));


        catlist.setOnItemClickListener(new OnItemClickListener() {

               @Override
               public void onItemClick(AdapterView<?> parent, View v,
                 final int position, long id) {


                Toast.makeText(MainActivity.this,
                  "List View Clicked:" + position, Toast.LENGTH_LONG)
                  .show();
               }
              });     

    }

    private void openAndQueryDatabase(int parentid) {
        DataBaseHelper db = new DataBaseHelper(this);

        SQLiteDatabase dbr = db.getReadableDatabase();
        cur = dbr.rawQuery(
                "SELECT _id, title, has_sub FROM categories where parent_id=?",
                new String[] { String.valueOf(parentid) });


        if (cur != null) {
            while (cur.moveToNext()) {

                int cat_id = cur.getInt(cur.getColumnIndex("_id"));
                String cattitle = cur.getString(cur.getColumnIndex("title"));
                int has_sub = cur.getInt(cur.getColumnIndex("has_sub"));
                results.add(cat_id + cattitle + has_sub);
            }
            cur.close();
        }

        db.close();

    }
}

1)我可以获得onItemClick的位置.但是我希望获得类别_id onItemClick.请帮忙

2)我是新人.我的代码有什么错误吗？

非常感谢

Answer 1

使用CursorAdapter(http://developer.android.com/reference/android/widget/CursorAdapter.html),当您使用ArrayAdapter时,它会超出内存分配,如果db更改,您也不会收到通知.

此外,如果您使用CursorAdapter,您将拥有

public void onItemClick(AdapterView<?> parent, View v, final int position, long id)

"id"参数将与表的_id字段一致

得到整排就行了

adapter.getItem(int position)