Question

我有一个带有ImageViews的gridView片段。在一个屏幕上放置了大约12个图像。我的项目中总共有大约1000张图片。图像存储在/ assets文件夹中。

我尝试按照谷歌文档使滚动顺利。它对我有所帮助，但根本没有。

我有一个问题，当我滚动时，我能够看到最后一行是如何重绘的。此外，如果我快速滚动，那么我将看到屏幕上的所有图像将如何重绘（旧图像按新方式更改）。而且当我快速滚动时，屏幕上的所有当前图像都会被冻结。只有在滚动停止时才会重新绘制图像。

有没有办法改善它？

我的自定义适配器：

public class GridViewAdapter extends BaseAdapter{
    private Context context;
    private List<Meme> memes;
    private String path;
    private LruCache<String, Bitmap> memoryCache;

    public GridViewAdapter(Context context, List<Meme> memes, String path){
        this.context = context;
        this.memes = memes;
        this.path = path;

        final int maxMemory = (int) (Runtime.getRuntime().maxMemory());
        final int cacheSize = maxMemory / 4;

        this.memoryCache = new LruCache<String, Bitmap>(cacheSize) {
            @Override
            protected int sizeOf(String key, Bitmap bitmap) {
                return bitmap.getByteCount();
            }
        };
    }
    @Override
    public int getCount() {
        return memes.size();
    }

    @Override
    public Object getItem(int position) {
        return memes.get(position);
    }

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

    static class ViewHolder{
        ImageView memeImage;
        int position;
    }
    @Override
    public View getView(final int position, View convertView, ViewGroup parent) {
        ViewHolder viewHolder;
        if(convertView == null){
            LayoutInflater inflater = (LayoutInflater) context
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = inflater.inflate(R.layout.grid_item, parent, false);
            viewHolder = new ViewHolder();
            viewHolder.memeImage = (ImageView) convertView.findViewById(R.id.meme_image);
            viewHolder.position = position;
            convertView.setTag(viewHolder);
        }
        else {
            viewHolder = (ViewHolder) convertView.getTag();
        }

        new AsyncTask<ViewHolder, Void, Bitmap>() {
            private ViewHolder v;

            @Override
            protected Bitmap doInBackground(ViewHolder... params) {
                String fullPath = path + "/" + memes.get(position).getTitle();
                v = params[0];
                Bitmap bitmap = getBitmapFromMemoryCache(fullPath);
                if(bitmap == null){
                    try {
                        InputStream is = context.getAssets().open(fullPath);
                        bitmap = BitmapFactory.decodeStream(is);
                        addBitmapToMemoryCache(fullPath, bitmap);
                    }
                    catch (IOException e){
                        e.printStackTrace();
                    }
                }
                return bitmap;
            }

            public void addBitmapToMemoryCache(String key, Bitmap bitmap) {
                if (getBitmapFromMemoryCache(key) == null) {
                    memoryCache.put(key, bitmap);
                }
            }

            public Bitmap getBitmapFromMemoryCache(String key) {
                return memoryCache.get(key);
            }

            @Override
            protected void onPostExecute(Bitmap result) {
                super.onPostExecute(result);
                if (v.position == position) {
                    // If this item hasn't been recycled already, hide the
                    // progress and set and show the image

                    v.memeImage.setImageBitmap(result);
                }

            }
        }.execute(viewHolder);
        viewHolder.position = position;
        return convertView;
    }


}

提前多多谢谢你。

我的平滑滚动实现有什么问题？

0 个答案: