同步适配器和带分页响应的REST服务器

Question

同步适配器和带分页响应的REST服务器

6

我需要了解如何处理来自Rest服务器的分页响应和同步适配器。我正在制作一个Android应用程序，用于检索数据集合。每一页都有20个项目，我现在正在一次性检索所有项目。我认为最好的方法是一次检索一页，例如滚动到列表视图的末尾，再使用同步适配器进行另一个请求，但我不确定。

我正在搜索如何在Android中处理REST中的分页，但我没有找到任何有用的信息。我想知道是否有人可以帮助我。

谢谢。

这是我现在如何检索项目的示例。

public ArrayList<ContentProviderOperation> parse(String json) throws IOException, NullPointerException {

    final ArrayList<ContentProviderOperation> batch = new ArrayList<ContentProviderOperation>();

    AccountManager manager = AccountManager.get(mContext);
    Account account = ((KipptApplication)mContext.getApplicationContext()).getCurrentAccount();
    String authToken = manager.peekAuthToken(account, AuthenticatorActivity.PARAM_AUTHTOKEN_TYPE);

    Header[] headers = new Header[]{
            new BasicHeader(KipptConstants.API_USERNAME_KEY,account.name),
            new BasicHeader(KipptConstants.API_TOKEN_KEY,authToken)
    };


    Gson gson = new Gson();
    Type responseType = new TypeToken<Response<ClipObject>>() {}.getType();
    Response<ClipObject> inbox = gson.fromJson(json,responseType);

    List<ClipObject> clips = inbox.getObjects();

    String response = null;
    String next = inbox.getMeta().getNext();

    while(next !=null){

        try {
            Log.d(TAG,"Fetching more clips from: " + next);
            response = HttpHelper.getHttpResponseAsString(KipptConstants.DOMAIN_URL +
                    next, null, headers);
            inbox = gson.fromJson(response,responseType);
            /*Updating next uri*/
            next = inbox.getMeta().getNext();
            if(!inbox.getObjects().isEmpty()){
                clips.addAll(inbox.getObjects());
            }else{
                Log.d(TAG,"No more clips");
                break;
            }
        } catch (PersonalizedException e) {
            Log.e(TAG,e.toString());
            e.printStackTrace();
        }
    }

    for(ClipObject clip : clips){
        if(mKipptDAO.isClipInDb(mContext.getContentResolver(),clip.getId(),true)== null){
            Log.i(TAG,"Adding new clip");
            /*Parsing clip*/
            parseClip(clip,batch,false /*Clip isn't in database so update=false*/);
            /*Parsing media*/
            parseMedia(clip.getMedia(),clip.getId(),batch,false);
            /*Parsing comments if clip contains it*/
            if(clip.getCommentObjects().getCount()>0) {
                List<CommentObject> comments = clip.getCommentObjects().getListElements();
                for(CommentObject comment: comments){
                    parseComments(comment,clip.getId(),batch,false);
                }
            }
            /*TODO Parse Likes*/

            /*Parsing user creator*/
            parseCreator(clip.getUserCreator(),batch,false);

        }else{
            Log.i(TAG,"Modifying clip");
            /*Clip is in database*/
            if(!(clip.getUpdated()<= timestamp)){
                /*Parsing clip and update it in database*/
                parseClip(clip,batch,true);
                /*Parsing media and update it in database*/
                parseMedia(clip.getMedia(),clip.getId(),batch,true);
                /*Parsing comments and update it in database*/
                if(clip.getCommentObjects().getCount()>0) {
                    List<CommentObject> comments = clip.getCommentObjects().getListElements();
                    for(CommentObject comment: comments){
                        parseComments(comment,clip.getId(),batch,true);
                    }
                }
                /*TODO parse likes*/

                /*Parse Creator*/
                parseCreator(clip.getUserCreator(),batch,true);
            }
        }
        /*Updating timestamp*/
        if(timestamp<=clip.getUpdated())timestamp = clip.getUpdated();

    }

    /*Saving timestamp modified value in preferences file*/
    this.sharedPreferences.edit().putLong(KipptConstants.loadTimeStamp(currentFragmentIndex), timestamp).commit();

    return batch;
}

- emaleavil

1个回答

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- Mohammad Hossein Gerami · Answer 1

如果要使用SyncAdapter，建议您尝试this。

此外，要检测RecyclerView中列表的末尾，请使用以下方法：

@Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
                    super.onScrollStateChanged(recyclerView, newState);

                // When went to the end of the list, load more posts
                if (newState == RecyclerView.SCROLL_STATE_IDLE) {

                    if (linearLayoutManager.findLastVisibleItemPosition() >= linearLayoutManager.getItemCount() - 1) {

                      // Grow List
                    }
                }
}