java - 画廊项目背景未随 setSelection 更改

Question

我有一个包含文本项目的图库。我可以使用 UI 或使用 setSelection(position) 以编程方式更改所选项目。但是，当我调用此方法时，有时项目背景不会更改为选定状态。我注意到，如果 setSelection 调用的项目已绘制在屏幕上，则其背景不会更新。

这是代码。欢迎任何帮助。

public class Test3 extends Activity {

  private static String[] items = {"0", "1", "2", "3", "4", "5"};

  public void onCreate (Bundle savedInstanceState) {
    super.onCreate (savedInstanceState);
    LinearLayout layout = new LinearLayout (this);
    layout.setOrientation (LinearLayout.VERTICAL);
    setContentView (layout);
    final Gallery gallery = new Gallery (this);
    layout.addView (gallery);
    gallery.setSpacing (0);
    gallery.setAdapter (new Adapter (this));
    gallery.setSelection (0);
    ListView list = new ListView (this);
    layout.addView (list);
    list.setAdapter (new ArrayAdapter <String> (this,
    android.R.layout.simple_list_item_1, items));
    list.setOnItemClickListener (new OnItemClickListener () {
      public void onItemClick (AdapterView <?> parent, View view, int position,
      long id)
      {
        gallery.setSelection (position);
      }
    });
  }

  private class Adapter extends ArrayAdapter <String> {

    public Adapter (Context context) {
      super (context, android.R.layout.simple_gallery_item, items);
    }

    public View getView (int position, View convertView, final ViewGroup parent)
    {
      TextView view = new TextView (getContext ());
      view.setText (getItem (position));
      view.setBackgroundResource (R.drawable.gallery_background);
      view.setGravity (Gravity.CENTER);
      view.setLayoutParams (new Gallery.LayoutParams (Test3.this
      .getWindowManager ().getDefaultDisplay ().getWidth () / 3,
      Gallery.LayoutParams.FILL_PARENT));
      return view;
    }
  }
}

gallery_background.xml

<?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/highlight_selected" />
  <item android:state_checked="true" android:drawable="@drawable/highlight_selected" />
  <item android:state_focused="true" android:drawable="@drawable/highlight_selected" />
  <item android:state_pressed="true" android:drawable="@drawable/highlight_pressed" />
  <item android:drawable="@drawable/highlight_disabled" />
</selector>

Answer 1

尝试使图库无效或notifyDataSetChanged图库适配器。