Android：从画廊中删除一个视图

Question

我在我的应用中使用了一个画廊视图。这个应用程序的设计使我可以从画廊中拖放一个视图。

我该如何从画廊中删除被拖动的视图？

- netimen

Answer 1

您需要从基础适配器中删除它。如果您正确执行此操作，则Gallery会自动刷新。否则，请在适配器上调用notifyDataSetChanged()来触发Gallery更新。

- CommonsWare

Answer 2

如果您覆盖ImageAdapter，您可以通过添加方法来删除或添加项目到您的图像列表中，或者在示例中，完全交换列表。我正在启动时显示应用程序横幅，然后更改Gallery以将应用程序模式显示为滑块。每当您调用修改ImageAdapter中数据集的方法时，请调用imageAdapter.notifyDataSetChanged()，如上所述：

    // in onCreate
    _gallery = (Gallery) this.findViewById(R.id.gallery_header);
    _imageAdapter = new ImageAdapter(getApplicationContext(),screen_width,screen_height);
    _imageAdapter.setBannerMode(true);        
    _gallery.setAdapter(_imageAdapter);


    // the main activity, in my case in a message handler.

    _imageAdapter.setBannerMode(false);
    _imageAdapter.notifyDataSetChanged();
    _gallery.setSelection(0,true);

    // this is my extended image adapter class

   import android.content.Context;
   import android.view.View;
   import android.view.ViewGroup;
   import android.widget.BaseAdapter;
   import android.widget.Gallery;
   import android.widget.ImageView;
   import android.widget.ImageView.ScaleType;

public class ImageAdapter extends BaseAdapter
{
    private Context _context = null;
    private int[] imageIds = { R.drawable.add_banner,R.drawable.subtract_banner,R.drawable.multiply_banner,R.drawable.divide_banner };
    private int[] bannerIds = { R.drawable.mathpiggie_banner };
    private static boolean bannerEnabled = true;

    int _screen_width;
    int _screen_height;

    public ImageAdapter(Context context, int screen_width, int screen_height) {
        this._context = context; 
        _screen_width = screen_width;
        _screen_height = screen_height; 
    }

    public void setBannerMode(boolean val)
    {
        bannerEnabled = val;
    }

    @Override
    public int getCount()
        {
            if (bannerEnabled)
                return bannerIds.length;
            else
                return imageIds.length;
        }

    @Override
    public Object getItem(int index)
        {
            if (bannerEnabled)
                    return bannerIds[index];
            else
                return imageIds[index];
        }

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

    @Override
    public View getView(int postion, View view, ViewGroup group)
        {
            ImageView imageView = new ImageView(_context);
            if (bannerEnabled)
                imageView.setImageResource(bannerIds[postion]);
            else
                imageView.setImageResource(imageIds[postion]);

             return imageView;
        }
}

- bill davis