Android从列表视图中获取复选框的值

Question

我有这段代码，我需要删除在列表视图中检查的数据，但我的问题是我只得到第一个复选框。当我选中第二个复选框时，它没有检索到数据。 getChildCount() 也返回 0 为什么会这样？我不知道我将如何解决我的问题。谢谢。

这是我的代码：

btnDel.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            RetailerDatabaseHelper dbHelper = new RetailerDatabaseHelper(TemplateActivity.this);
            final SQLiteDatabase db = dbHelper.getReadableDatabase();
            CheckBox cb = (CheckBox) findViewById(R.id.checkBox1); //For further investigation!

            Cursor c10 = db.query("Retailer", new String[]{"_id", "name", "validity"}, null, null, null, null, null, null);
            ListAdapter adapter = new SimpleCursorAdapter(TemplateActivity.this, R.layout.custom_dialog_box, c10, new String[]{"name", "validity"}, new int[]{R.id.checkBox1, R.id.number}, 0);
            ListView myList = (ListView) findViewById(R.id.listview);
            myList.setAdapter(adapter);

            Log.d("Inside Button", "Test Child: " + myList.getChildCount() + " Adapter: " + adapter.getCount() + " getAdapter: " + myList.getAdapter().getCount() + " Child: " + myList.getChildAt(1));

            for(int x = 0; x < myList.getAdapter().getCount(); x++)
            {
                View nextChild = myList.getChildAt(x);
                if(nextChild instanceof CheckBox)
                {
                    CheckBox checkbox = (CheckBox)nextChild;
                    if(checkbox.isChecked())
                    {
                        Toast.makeText(getApplicationContext(), "Checked", Toast.LENGTH_SHORT).show();
                    }
                }
            }
        }
    });

Answer 1

我会先说：永远不要在 Android 的 UI/主线程上进行数据库工作。它将阻塞 UI 并导致您的应用程序冻结。查看this resource for more info 的“线程”部分。

要解决您当前的问题，您可能需要维护一个“已检查”项目的列表。这可能涉及维护已使用 a listener on your check boxes 填充的 id 列表，您可以在列表的适配器视图绑定代码中设置该列表。在检查更改后，您可以将 id 添加到您的列表中，并在删除时告诉您的数据库需要删除哪些 id。对于此解决方案，您可能需要研究制作自己的适配器。简单的光标适配器不会让你走得太远；）

另外，您可能想查看 RecyclerView - ListView 的较新版本。

Answer 2

@Kathleen51
我在 BaseAdapter 中使用 SparseBooleanArray。像这样编辑您的代码...

class OutPatientServiceAdapter extends BaseAdapter {
    private LayoutInflater inflater;
    private ArrayList<OutPatientService> beans;
    private viewHolder holder;
    private Context c;
    private SparseBooleanArray booleanArray;

    public OutPatientServiceAdapter(Context c,
            ArrayList<OutPatientService> beans) {
        super();
        this.c = c;
        this.beans = beans;
        inflater = LayoutInflater.from(c);
        booleanArray = new SparseBooleanArray(beans.size());
        for (int i = 0; i < beans.size(); i++) {
            booleanArray.put(i, true);
        }
    }

    @Override
    public int getCount() {
        return beans.size();
    }

    @Override
    public OutPatientService  getItem(int position) {
        return beans.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(final int position, View convertView,
            ViewGroup parent) {
        holder = new viewHolder();
        final OutPatientService bean = (OutPatientService) getItem(position);
        if (convertView == null) {
            convertView = inflater.inflate(
                    R.layout.outpatient_service_item, parent, false);
            holder.itemText = (CheckBox) convertView
                    .findViewById(R.id.itemText);
            holder.doctorText = (TextView) convertView
                    .findViewById(R.id.doctorText);
            holder.priceText = (TextView) convertView
                    .findViewById(R.id.priceText);
            convertView.setTag(holder);
        } else {
            holder = (viewHolder) convertView.getTag();
        }
        boolean check = booleanArray.get(position);
        holder.itemText.setChecked(check);
        holder.itemText
                .setOnCheckedChangeListener(new OnCheckedChangeListener() {

                    @Override
                    public void onCheckedChanged(CompoundButton buttonView,
                            boolean isChecked) {
                        booleanArray.put(position, isChecked);
                    }
                });
        holder.itemText.setText(bean.recipe_name);
        holder.doctorText.setText(bean.create_doctor);
        holder.priceText.setText(bean.fee);
        return convertView;
    }

    public class viewHolder {
        public CheckBox itemText;
        public TextView doctorText;
        public TextView priceText;
    }

    public SparseBooleanArray getmSpCheckedState() {
        return booleanArray;
    }

    public void selectAll() {
        for (int i = 0; i < beans.size(); i++) {
            if (!booleanArray.get(i)) {
                booleanArray.put(i, true);
            }
        }
        notifyDataSetChanged();
    }

    public void clearAll() {
        for (int i = 0; i < beans.size(); i++) {
            if (booleanArray.get(i)) {
                booleanArray.put(i, false);
            }
        }
        notifyDataSetChanged();
    }
}