java - 仅可绘制的 ListView

Question

我有一个动态的可绘制对象数组，并希望将它们显示在可滚动列表中。我最遇到麻烦的是阵列适配器。这段代码没有出现任何编译时错误，但我得到的运行时错误是 -

Process: com.example.michael.myandroidappactivity, PID: 12297
java.lang.IllegalStateException: ArrayAdapter requires the resource ID to be a TextView

但我不想使用 TextView !这是主要代码-

public class cards extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_show_old_cards);
    ListView list = (ListView)findViewById(R.id.showCardList);
    cardPile tmp = cardPile.getInstance();
    ArrayList<Integer> discardPile = tmp.getDiscardPile();
    ArrayAdapter<Integer> imgAdapt = new ArrayAdapter<Integer>(this,R.layout.listview_layout,discardPile);
    list.setAdapter(imgAdapt);
}

}

Answer 1

您必须创建一个新类来扩展 BaseAdapter界面并修改getView方法返回您想要在 ListView 中显示的 View 。例如:

public class ImageAdapter extends BaseAdapter
{
private Context context;
private ArrayList<Integer> imagesIds;

public ImageAdapter(Context _context, ArrayList<Integer> _imageIds)
{
    context = _context;
    imageIds = _imageIds;
}


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

@Override
public Object getItem(int position)
{
    return null; 
}

@Override
public long getItemId(int position) {
    return 0;
}

@Override
public View getView(int position, View convertView, ViewGroup parent)
{
    ImageView view;

    if( convertView != null ) // recycle call
    {
        view = (ImageView) convertView;
    }
    else
    {
        view = new ImageView(context);
        image.setBackgroundResource(imageIds.get(position));
    }

    return view;
}
}

然后将您的 listView 适配器修改为:

list.setAdapter( new ImageAdapter( this, discardPile) );