Android adapter.getItem(position).getItemId() 不工作（方法 getId() 未定义对象类型）

Question

我有一个列表视图，我正在使用自定义适配器将数据填充到列表视图表单数据库中。它工作正常，但是当我单击列表项时，我想获取被单击的项目的 ID，以将其传递给下一个活动以做一些事情。但是当我单击列表项时，我无法获取 ID。 知道为什么会这样吗？

我的列表监听器：

    list.setOnItemClickListener(new OnItemClickListener() {

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


                    Intent intent = new Intent(MainActivity.this,
                            CountryActivity.class);
                     intent.putExtra("countryId", adapter.getItem(position).getId());//here i am getting error saying 
          //The method getId() is undefined for the type Object.

                    startActivity(intent);

                }
            });

但我已经为类型规范定义了我的 countries.java (POJO)

public class Countries {
    Integer id;
    String countryName = "", countryIcon = "";

    public Countries(Integer id, String countryName, String countryIcon) {

        this.id = id;
        this.countryName = countryName;
        this.countryIcon = countryIcon;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getCountryName() {
        return countryName;
    }

    public void setCountryName(String countryName) {
        this.countryName = countryName;
    }

    public String getCountryIcon() {
        return countryIcon;
    }

    public void setCountryIcon(String countryIcon) {
        this.countryIcon = countryIcon;
    }

}

我正在从以下代码中从光标 obj（签证）中获取数据：

names = new ArrayList<Countries>();
        do {

            country = new Countries(Integer.parseInt(visas.getString(0)),
                    visas.getString(1), visas.getString(2));

            // Log.d("VISA", visas.getString(0));

            names.add(country);

        } while (visas.moveToNext());

这是我的适配器代码：

public class VisaAdapter extends ArrayAdapter<Countries> {
    private final Context context;
    private final ArrayList<Countries> values;
    Resources resc = getContext().getResources();

    public VisaAdapter(Context context, ArrayList<Countries> values) {
        super(context, R.layout.list_item, values);
        this.context = context;
        this.values = values;
    }

    @Override
    public Countries getItem(int position) {
        return values.get(position);
    }

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

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        LayoutInflater inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

        View rowView = inflater.inflate(R.layout.list_item, parent, false);
        TextView textView = (TextView) rowView.findViewById(R.id.label);
        ImageView imageView = (ImageView) rowView.findViewById(R.id.logo);
        textView.setText(values.get(position).getCountryName());

        // Change icon based on name
        String icon = values.get(position).getCountryIcon();
        int resIcon = resc.getIdentifier(icon, "drawable", "com.m7.visaapp");

        rowView.setBackgroundResource(R.drawable.list_view_places_row);

        imageView.setImageResource(resIcon);

        return rowView;
    }

}

Answer 1

您必须将 getItem(position) 返回值强制转换为 Countries 对象。

改变这个：

    intent.putExtra("countryId", adapter.getItem(position).getId());

到这里：

    Countries countries = (Countries)adapter.getItem(position);
    intent.putExtra("countryId", countries.getId());

---

更新：

实际上，在阅读@Tushar 的评论后，我认为您应该将names 设为VisaAdapter 而不是ArrayList<Countries>()。然后，您上面的原始代码行应该可以按原样工作。

Answer 2

adapter.getItem(position)

函数返回一个Object，因此将其类型转换为 Country like

(Countries)adapter.getItem(position)