Question

我尝试使用从MOVIE db API获取的数据更新我的回收站视图。我使用ASYNC任务发出请求并从服务器获取结果，但在onPostExecute（）中，当我尝试清除适配器并将新数据添加到适配器时，它显示“无法解析方法”clear（）' “

MAINACTIVITY

public class MainActivity extends AppCompatActivity {

    final static QueryUtils queryUtils = new QueryUtils();
    final static String URL = "http://api.themoviedb.org/3/movie/popular?    api_key=";
    static String[] finalData = new        String[queryUtils.getLengthOfJsonArray(URL)];
    public RecyclerView mRecyclerView;
    public RecyclerView.Adapter mAdapter;
    private RecyclerView.LayoutManager mLayoutManager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mRecyclerView = (RecyclerView) findViewById(R.id.recylerView);
        //using the grid layout manager
        mLayoutManager = new GridLayoutManager(getApplicationContext(), 2);
        mRecyclerView.setLayoutManager(mLayoutManager);
        //setting the adpater.
        mAdapter = new MovieAdapter(finalData, this);
        mRecyclerView.setAdapter(mAdapter);
        MovieTask task =new MovieTask();
        task.execute(URL);    
    }

    private class MovieTask extends AsyncTask<String, Void, String[]> {

        @Override
        protected String[] doInBackground(String... params) {
            String[] data = queryUtils.fetchMovieData(URL);
            return data;
        }

        @Override
        protected void onPostExecute(String[] data) {
            mAdapter.clear();
        }
    }
}

电影适应性活动

public class MovieAdapter extends RecyclerView.Adapter<MovieAdapter.ViewHolder>{

    private String[] adumyString;
    private int[] adumyimage;
    private Context context;

    //Constructor for Movie Adapter
    public MovieAdapter(String[] dummyDataSet,Context context) {
        this.context=context;
        adumyString=dummyDataSet;
    }

    // Provide a direct reference to each of the views within a data item
    // Used to cache the views within the item layout for fast access
    public static class ViewHolder extends RecyclerView.ViewHolder {
        // Your holder should contain a member variable
        // for any view that will be set as you render a row
        public ImageView colorImageView;

        // We also create a constructor that accepts the entire item row.
        // and does the view lookups to find each subview
        public ViewHolder(View itemView) {
            // Stores the itemView in a public final member variable that can be used
            // to access the context from any ViewHolder instance.
            super(itemView);
            colorImageView = (ImageView) itemView.findViewById(R.id.movieImage);
        }
    }
    /**
     * Binds the data into
     */
    @Override
    public void onBindViewHolder(MovieAdapter.ViewHolder holder, int position) {
        Picasso.with(context).load(adumyString[position]).into(holder.colorImageView);
    }

    @Override
    public int getItemCount() {
        return adumyString.length;
    }

    /**
     * Inflates the out custom view on to the screen.
     */
    @Override
    public MovieAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.image_view,parent,false);
        return new ViewHolder(v);
    }
}

Answer 1

RecyclerView.Adapter抽象类不提供任何clear或add方法。请参阅课程here的文档。

您必须在MovieAdapter课程中声明并实施这些方法，并将mAdapter变量声明为MovieAdapter mAdapter;。

Answer 2

您可以在adapter.notifydatasetchanged()方法中使用onPostExecute()。

ps：很抱歉在这里写评论，低代表：）

无法解决Recyclerview中的方法“clear（）”

2 个答案: