1

我有以下代码用于在我的 android 网格视图中显示一些 url 图像。问题是，将少量图像显示到我的网格视图中需要很多时间。这些是我的代码：

public class GridViewImageAdapter extends BaseAdapter {
private Activity activity;
private ArrayList<HashMap<String, String>> galleryAttributes = new ArrayList<HashMap<String, String>>();
private int imageWidth;
int ctr = 0;

public GridViewImageAdapter(Activity activity,
        ArrayList<HashMap<String, String>> galleryAttributes, int imageWidth) {
    this.activity = activity;
    this.galleryAttributes = galleryAttributes;
    this.imageWidth = imageWidth;
}

@Override
public int getCount() {
    // TODO Auto-generated method stub
    return galleryAttributes.size();
}

@Override
public Object getItem(int position) {
    // TODO Auto-generated method stub
    return galleryAttributes.get(position);
}

@Override
public long getItemId(int position) {
    // TODO Auto-generated method stub
    return position;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    // TODO Auto-generated method stub


    ImageView imageView;
    if(convertView == null){
        imageView = new ImageView(activity);
    }else{
        imageView = (ImageView) convertView;
    }

    LoadImage loadImage = new LoadImage();

    try {
        Bitmap image = loadImage.execute(galleryAttributes.get(position).get("Link")).get();
        imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
        imageView.setLayoutParams(new GridView.LayoutParams(imageWidth, imageWidth));
        imageView.setImageBitmap(image);

    } catch (InterruptedException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (ExecutionException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }   

    return imageView;   
}


public class LoadImage extends AsyncTask<String, String, Bitmap>{

    @Override
    protected Bitmap doInBackground(String... params) {
        // TODO Auto-generated method stub
        try{
            BitmapFactory.Options o = new BitmapFactory.Options();
            o.inJustDecodeBounds = true;
            BitmapFactory.decodeStream((InputStream) new URL(params[0]).getContent(), null, o);
            final int REQUIRED_WIDTH = imageWidth;
            final int REQUIRED_HEIGHT = imageWidth;
            int scale = 1;
            while (o.outWidth / scale / 2 >= REQUIRED_WIDTH
                    && o.outHeight / scale / 2 >= REQUIRED_HEIGHT)
                scale *= 2;
            BitmapFactory.Options o2 = new BitmapFactory.Options();
            o2.inSampleSize = scale;
            return BitmapFactory.decodeStream((InputStream) new URL(params[0]).getContent(), null, o2);
        }

        catch(Exception e){
            e.printStackTrace();
        }
        return null;
    }   
}
4

2 回答 2

0

尝试使用毕加索

http://square.github.io/picasso/

这个库会缓存从 URL 下载的图片，下次打开它时，它会加载得更快，因为您不需要再次下载它，只需从缓存中获取它。

如果初始显示也很慢，请尝试将其调整到合理的大小。

用法也很简单：

Picasso.with(context)
  .load(url)
  .resize(50, 50)
  .centerCrop()
  .into(imageView)
于 2014-10-08T06:22:31.223 回答
0

您可以使用 Glide 或 Picasso。但 Glide 也有缩略图支持。

Glide.with(this) .load(galleryAttributes.get(position).get("Link")) .thumbnail(0.1f) .into(imageView);

Picasso.with(this).load(galleryAttributes.get(position).get("Link")).into(imageView);

于 2014-10-08T06:37:22.990 回答