Question

我希望在我的应用中将图片列表设为GridView。我正在使用ImageAdapter课程来初始化GridView。

这是我的ImageAdapter课程：

public class ImageAdapter extends BaseAdapter {
   private Context mContext;

   // Constructor
   public ImageAdapter(Context c) {
      mContext = c;
   }

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

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

   public long getItemId(int position) {
      return 0;
   }

   // create a new ImageView for each item referenced by the Adapter
   public View getView(int position, View convertView, ViewGroup parent) {
      ImageView imageView;

      if (convertView == null) {
         imageView = new ImageView(mContext);
         imageView.setLayoutParams(new GridView.LayoutParams(85, 85));
         imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
         imageView.setPadding(8, 8, 8, 8);
      } 
      else 
      {
         imageView = (ImageView) convertView;
      }
      imageView.setImageResource(mThumbIds[position]);
      return imageView;
   }

   // Keep all Images in array
   public Integer[] mThumbIds = {
      R.drawable.sample_2, R.drawable.sample_3,
      R.drawable.sample_4, R.drawable.sample_5,
      R.drawable.sample_6, R.drawable.sample_7,
      R.drawable.sample_0, R.drawable.sample_1,
      R.drawable.sample_2, R.drawable.sample_3,
      R.drawable.sample_4, R.drawable.sample_5,
      R.drawable.sample_6, R.drawable.sample_7,
      R.drawable.sample_0, R.drawable.sample_1,
      R.drawable.sample_2, R.drawable.sample_3,
      R.drawable.sample_4, R.drawable.sample_5,
      R.drawable.sample_6, R.drawable.sample_7
   };
}

但我想使用ArrayList<Bitmap>代替Integer[] mThumbIds。

我的Bitmap arraylist是这样的：

ArrayList<Bitmap> bitmaps = new ArrayList<Bitmap>();

byte[] data = null;

for (int i = 0; i<image.size(); i++) {
    try {
        data = Base64.decodeBase64(image.get(i).getBytes("UTF-8"));
    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    }

    bitmaps.add(BitmapFactory.decodeByteArray(data, 0, data.length));
}

我该怎么做？

Answer 1

您只需使用ImageView中的setImageBitmap()方法即可。

在您的特定情况下，在ImageAdapter类上，在构造函数上传递Bitmap数组。

private ArrayList<BitMap> images;

// Constructor
public ImageAdapter(Context c, ArrayList<BitMap> images) {
    mContext = c;
    this.images = images;
}

然后，在getView()方法上，将图像设置为：

imageView.setImageBitmap(images.get(position);

你可以安全地删除它：

// Keep all Images in array
public Integer[] mThumbIds = {
   R.drawable.sample_2, R.drawable.sample_3,
   R.drawable.sample_4, R.drawable.sample_5,
   R.drawable.sample_6, R.drawable.sample_7,
   R.drawable.sample_0, R.drawable.sample_1,
   R.drawable.sample_2, R.drawable.sample_3,
   R.drawable.sample_4, R.drawable.sample_5,
   R.drawable.sample_6, R.drawable.sample_7,
   R.drawable.sample_0, R.drawable.sample_1,
   R.drawable.sample_2, R.drawable.sample_3,
   R.drawable.sample_4, R.drawable.sample_5,
   R.drawable.sample_6, R.drawable.sample_7
};

Answer 2

不是将mThumbIds传递给适配器，而是传递位图的arraylist。

如果要解码位图，则需要特别小心，以免在UI线程上完成。这可以使用AsyncTask完成。请参阅：http://developer.android.com/training/displaying-bitmaps/process-bitmap.html

另外，对于缓存位图，要缓存的位图数量应取决于可用内存。

在android中的gridview中插入位图数组而不是drawables

2 个答案: