如何在Android中膨胀可扩展列表

Question

我想膨胀一个可扩展的列表与一些不同的文本和不同的图像上的每一行，如果我使用albumCovers.get(i)而不是getResources().getDrawable(R.drawable.icon)然后它抛出一个错误，有人帮助我们吗?谢谢,p .

public class ExpandActivity extends ExpandableListActivity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    // Construct Expandable List
    final String NAME = "name";
    final String IMAGE = "image";
    final LayoutInflater layoutInflater = (LayoutInflater) this
            .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    final ArrayList<HashMap<String, String>> headerData = new ArrayList<HashMap<String, String>>();
    final HashMap<String, String> group1 = new HashMap<String, String>();
    group1.put(NAME, "Group 1");
    headerData.add(group1);
    final ArrayList<ArrayList<HashMap<String, Object>>> childData = new ArrayList<ArrayList<HashMap<String, Object>>>();
    final ArrayList<HashMap<String, Object>> group1data = new ArrayList<HashMap<String, Object>>();
    childData.add(group1data);
    Resources res = this.getResources();
    Drawable photo = (Drawable) res.getDrawable(R.drawable.icon);
    ArrayList<Drawable> albumCovers = new ArrayList<Drawable>();
    albumCovers.add(photo);
    // Set up some sample data in both groups
    for (int i = 0; i < 10; ++i) {
        final HashMap<String, Object> map = new HashMap<String, Object>();
        map.put(NAME, "Child " + i);
        map.put(IMAGE, getResources().getDrawable(R.drawable.icon));
        (group1data).add(map);
    }
    setListAdapter(new SimpleExpandableListAdapter(this, headerData,
            android.R.layout.simple_expandable_list_item_1,
            new String[] { NAME }, // the name of the field data
            new int[] { android.R.id.text1 }, // the text field to populate
                                                // with the field data
            childData, 0, null, new int[] {}) {
        @Override
        public View getChildView(int groupPosition, int childPosition,
                boolean isLastChild, View convertView, ViewGroup parent) {
            final View v = super.getChildView(groupPosition, childPosition,
                    isLastChild, convertView, parent);
            // Populate your custom view here
            ((TextView) v.findViewById(R.id.name))
                    .setText((String) ((Map<String, Object>) getChild(
                            groupPosition, childPosition)).get(NAME));
            ((ImageView) v.findViewById(R.id.image))
                    .setImageDrawable((Drawable) ((Map<String, Object>) getChild(
                            groupPosition, childPosition)).get(IMAGE));
            return v;
        }
        @Override
        public View newChildView(boolean isLastChild, ViewGroup parent) {
            return layoutInflater.inflate(
                    R.layout.expandable_list_item_with_image, null, false);
        }
    });
}
}

Answer 1

你只有一个可以在albumCovers中绘制，但在for循环中循环它十次，并尝试通过索引访问它。修改albumCovers.get(i)为albumCovers.get(0)使其工作

这里是关键位置:

Drawable photo = (Drawable) res.getDrawable(R.drawable.icon); 
ArrayList<Drawable> albumCovers = new ArrayList<Drawable>();
albumCovers.add(photo); // HERE: photo added only once!
for (int i = 0; i < 10; ++i) {
    final HashMap<String, Object> map = new HashMap<String, Object>();
    map.put(NAME, "Child " + i);
    map.put(IMAGE, getResources().getDrawable(R.drawable.icon)); // HERE: you wanted to use albumCovers.get(i) here. There is only 1 photo in albumCovers but you try to get images 0...9 from it using index i. So, change this to albumCovers.get(0) OR add 10x photo into albumCovers.
    (group1data).add(map);
}