android - 如何确保更改所选 GridView 单元格的背景？

Question

在 Android 中，我有一个 GridView - GridView 中的每个单元格都是一个 ImageView。当用户点击一个单元格时，我希望该单元格被“选中”(背景变为蓝色)，所有其他单元格“取消选中”(背景变为白色)。

我已经实现了以下背景可绘制对象，但它只会在按下单元格时更改背景:

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
 <item android:state_pressed="true"
       android:drawable="@drawable/iconborder_selected" /> <!-- pressed -->
 <item android:drawable="@drawable/iconborder_unselected" /> <!-- default -->
</selector>

编辑:这是我的 GridView 适配器代码。

class IconAdapter extends BaseAdapter {

    private Context context = null;
    private List<Drawable> icons = new ArrayList<Drawable>();

    public IconAdapter(Context context) {
        this.context = context;

        for (Field f : R.drawable.class.getFields()) {
            String path = f.getName();
            if (path.contains("icon_")) {
                int id = context.getResources().getIdentifier(path, "drawable",
                        context.getPackageName());
                Drawable drawable = context.getResources().getDrawable(id);
                icons.add(drawable);
            }
        }
    }

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

    @Override
    public Object getItem(int position) {
        return icons.get(position);
    }

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

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ImageView iv = new ImageView(context);
        iv.setImageDrawable(icons.get(position));
            iv.setBackgroundResource(R.drawable.iconborder);
        return iv;
    }

}

Answer 1

您还应该添加 state_selected:

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
  <item android:state_selected="true"
       android:drawable="@drawable/iconborder_selected" /> <!-- selected -->

  <item android:state_pressed="true"
       android:drawable="@drawable/iconborder_pressed" /> <!-- pressed -->

  <item android:state_pressed="false"
       android:drawable="@drawable/iconborder_unselected" /> <!-- default -->
</selector>