Question

我试图创建具有不同类别的应用程序，每个类别它有一组图片，我从第一个类别开始（10个图像）工作正常，但当我移动到另一个类别我的应用程序运行缓慢。我正在使用GridView

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,    Bundle savedInstanceState) {
    ArrayList<String> movieList =  new ArrayList<>();
    movieList.add("https://scontent-waw1-1.xx.fbcdn.net/v/t1.0-   9/18199348_430451573995024_7473960282002692779_n.jpg?oh=8667ffcd3ccb66892fcf4e7330f24e61&oe=59B88B8F");
    View v =  inflater.inflate(R.layout.fragment_art, container, false);
    myGrid= (GridView) v.findViewById(R.id.gridViewCategory);
    adapter =new CategoryAdapter(getActivity(),movieList);
    myGrid.setAdapter(adapter);
    return v;
    }

  }

class CategoryAdapter extends BaseAdapter {
   private Context context;
   private ArrayList<String> imageId=new ArrayList<String>();
   CategoryAdapter(Context context,ArrayList<String> imageId){
        this.context=context;
        this.imageId=imageId;
  }
   @Override
   public int getCount() {
    return imageId.size();
}
@Override
public Object getItem(int position) {
    return imageId.get(position);
}
@Override
public long getItemId(int position) {
    return position;
}
class ViewHolder{
    ImageView CategoryImage;
    ViewHolder(View view){
        CategoryImage = (ImageView) view.findViewById(R.id.cat_imageView);
    }
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
    View row=convertView;
    ViewHolder holder=null;
    if(row == null){
        LayoutInflater inflater= (LayoutInflater)    context.getSystemService(context.LAYOUT_INFLATER_SERVICE);
        row=inflater.inflate(R.layout.picture_item,parent,false);
        holder = new ViewHolder(row);
        row.setTag(holder);
    }
    else{
        holder=(ViewHolder) row.getTag();
    }   Glide.with(context).load(imageId.get(position)).placeholder(R.drawable.load).int       o(holder.CategoryImage);
       return row;
    }

 }

Answer 1

AsyncTasks是你的关键！

//使用AsyncTask在后台线程中加载慢图像

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

    @Override
    protected Bitmap doInBackground(ViewHolder... params) {
        v = params[0];
        return mFakeImageLoader.getImage();
    }

    @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.progress.setVisibility(View.GONE);
            v.icon.setVisibility(View.VISIBLE);
            v.icon.setImageBitmap(result);
        }
    } }.execute(holder);

或者您可以在gridview上启用快速滚动。此外，如果要切换到网格的新视图，则可以回收不需要的位图。

如果这些没有帮助，那么尝试使用像Glide这样的库。

希望这有帮助！

在类别（项目导航视图）之间移动时性能降低

1 个答案: