在android

Question

我是Android的新手，我正在制作一个响铃调整下载器应用程序。在这个应用程序中，我有一个回收视图与振铃曲调列表。当用户点击下载按钮时，我想在每个单元格中显示进度条。我知道RecyclerView会回收任何旧视图，因此需要绕过至少进度条。

实现这一目标的理想方法是什么？

我的适配器类

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

    //to reference the Activity
    private final Activity context;
    private final RecyclerViewClicks recyclerViewClicks;
    private final ArrayList<Track> trackList;



    public TrackListAdapter(Activity context, ArrayList<Track> trackList, RecyclerViewClicks recyclerViewClicks){

        this.context = context;
        this.recyclerViewClicks = recyclerViewClicks;
        this.trackList = trackList;


    }


    public ArrayList<Track> getData() {
        return this.trackList;
    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

        LayoutInflater inflater = LayoutInflater.from(context);
        View view = inflater.inflate(R.layout.tracklist_row,null);
        TrackListView rowView = new TrackListView(view);

        return rowView;
    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {

        Track currentTrack = this.trackList.get(position);

        TrackListView trackListView = (TrackListView) holder;
        trackListView.title.setText(currentTrack.getName());
        trackListView.track.setText(currentTrack.getArtist());
        Picasso.get().load(currentTrack.getArtUrl())
                .resize(100,100)
                .into(trackListView.imageView);

//        if(currentTrack.isDownloaded())
//        {
//            trackListView.download.setVisibility(View.INVISIBLE);
//        }
//        else
//        {
//            trackListView.download.setVisibility(View.INVISIBLE);
//        }

    }



    @Override
    public int getItemCount() {
        return trackList.size();
    }

    class TrackListView extends RecyclerView.ViewHolder implements View.OnClickListener, View.OnLongClickListener
    {

        TextView title, track;
        ImageView imageView;
        Button download;
        ProgressBar progressBar;
        TextView progressText;
      //  DownloadProgress downloadProgress;

        public ProgressBar getProgressBar() {
            return progressBar;
        }

        public TrackListView(View itemView) {
            super(itemView);

            title = itemView.findViewById(R.id.name);
            track = itemView.findViewById(R.id.track);
            imageView = itemView.findViewById(R.id.imageView);
            download = itemView.findViewById(R.id.download);
            progressBar = itemView.findViewById(R.id.progressBar);
            progressText = itemView.findViewById(R.id.downloadProgress);



            itemView.setOnClickListener(this);
            download.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    recyclerViewClicks.onButtonClicked(getAdapterPosition(),view,(Button) view);
                }
            });



        }


        @Override
        public void onClick(View view) {

        }

        @Override
        public boolean onLongClick(View view) {
            return false;
        }
    }



}

主要活动

public class MainActivity extends AppCompatActivity {



    ArrayList<Track> tracks = new ArrayList<Track>();
    RecyclerView trackListView;
    TrackListAdapter trackListAdapter;
    private File direct;
    final private int REQUEST_CODE_ASK_PERMISSIONS = 123;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        AndroidNetworking.initialize(getApplicationContext());



         trackListAdapter = new TrackListAdapter(this, tracks, new RecyclerViewClicks() {
             @Override
             public void onItemSelected(int position, View v) {

             }

             @Override
             public void onButtonClicked(int position, View cell, Button button) {

                 Track selectedTrack = tracks.get(position);
                 downloadMusic(selectedTrack,cell);

             }

             @Override
             public void onLongClicked(int position) {

             }
         });
//
        trackListView = (RecyclerView) findViewById(R.id.trackListView);
        trackListView.setLayoutManager(new LinearLayoutManager(this));
        trackListView.setAdapter(trackListAdapter);
......
......

我正在使用AndroidNetworking libs从服务器下载数据。 请帮忙

Answer 1

这是我为RecyclerView构建的内容，其中的单元格包含内容布局，该内容布局在单击时会加载mp3音频广播。 第一种方法是最佳的，因为它可以将加载信息临时存储在内存中，而第二种方法更适合于存储需要长时间存储的信息，而不是UI数据。

将状态加载到内存中（最佳解决方案）

在 RecyclerView 中选择内容后， ViewModel 会存储唯一项目ID的Array或HashMap。加载 RecyclerView 单元格的内容后，它将Array或HashMap中内容ID的视图状态更改为已加载。布局绑定到 ViewModel 并相应显示 ProgressBar 。

在磁盘上加载状态

Content 模型包含一个属性，以便在Room SQLite数据库中更新加载状态。布局已经是绑定到 Content 模型的数据，并且将根据模型的属性显示加载栏。