Android - GridView 中资产文件夹中的图像

Question

我一直致力于创建图像的网格视图，图像存在于资产文件夹中。 从 android 中的资产文件夹中打开文件链接帮助我使用位图来读取它。当前的代码是：

 public View getView(final int position, View convertView, ViewGroup parent) 
{

  try 
    {
     AssetManager am = mContext.getAssets();
     String list[] = am.list("");
     int count_files = imagelist.length;
     for(int i= 0;i<=count_files; i++)
     {
      BufferedInputStream buf = new BufferedInputStream(am.open(list[i]));
      Bitmap bitmap = BitmapFactory.decodeStream(buf);
      imageView.setImageBitmap(bitmap);
      buf.close();
     }
   }   
   catch (IOException e) 
   {
   e.printStackTrace();
   }
  }

我的应用程序确实从资产文件夹中读取图像，但它没有迭代网格视图中的单元格。网格视图的所有单元格都具有从图像集中选取的相同图像。谁能告诉我如何迭代单元格并且仍然有不同的图像？

我在扩展 BaseAdapter 类的 ImageAdapter 类中有上述代码，在我的主类中，我通过以下方式将其与我的 gridview 链接起来：

    GridView  gv =(GridView)findViewById(R.id.gridview);
    gv.setAdapter(new ImageAdapter(this, assetlist));       

非常感谢您提前提供的任何帮助， 萨兰

Answer 1

Saran，下面是我用来显示资源文件夹中的图像和图库的内容。我想这与 gridview 的处理是一样的：

public class myActivitye extends Activity
{
    private Gallery mGallery;

    @Override
    public void onCreate(Bundle savedInstanceState)
    {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        mGallery = (Gallery) findViewById(R.id.mygalleryinxml);

        //load images into memory
        mBitArray = new Bitmap[4];
        try
        {
            //these images are stored in the root of "assets"
            mBitArray[0] = getBitmapFromAsset("pic1.png");
            mBitArray[1] = getBitmapFromAsset("pic2.png");
            mBitArray[2] = getBitmapFromAsset("pic3.png");
            mBitArray[3] = getBitmapFromAsset("pic4.png");
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }

        mGallery.setAdapter(new GalleryAdapter(this, mBitArray));
    }

    public class GalleryAdapter extends BaseAdapter
    {
        //member variables
        private Context mContext;
        private Bitmap[] mImageArray;

        //constructor
        public GalleryAdapter(Context context, Bitmap[] imgArray)
        {
            mContext = context;
            mImageArray = imgArray;
        }

        public int getCount()
        {
            return mImageArray.length;
        }

        public Object getItem(int position)
        {
            return position;
        }

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

        //returns the individual images to the widget as it requires them
        public View getView(int position, View convertView, ViewGroup parent)
        {
            final ImageView imgView = new ImageView(mContext);

            imgView.setImageBitmap(mImageArray[position]);

            //put black borders around the image
            final RelativeLayout borderImg = new RelativeLayout(mContext);
            borderImg.setPadding(20, 20, 20, 20);
            borderImg.setBackgroundColor(0xff000000);//black
            borderImg.addView(imgView);
            return borderImg;
        }

    }//end of: class GalleryAdapter


    /**
     * Helper Functions
     * @throws IOException 
     */
    private Bitmap getBitmapFromAsset(String strName) throws IOException
    {
        AssetManager assetManager = getAssets();

        InputStream istr = assetManager.open(strName);
        Bitmap bitmap = BitmapFactory.decodeStream(istr);
        istr.close();

        return bitmap;
    }
}

Answer 2

无需每次都阅读所有项目。只读取 getView 方法调用中给定位置的项目。并且当时只显示该项目。

BufferedInputStream buf = new BufferedInputStream(am.open(list[position]));