我想用Adapters＆amp;编码无限滚动RecyclerViews和我从JSON用Volley获取我的物品。虽然我已阅读这些指南（Codepath和github），但我发现很难将其应用到我自己的场景中。
我的json的网址格式为：https://example.com/json/items?page=1，https://example.com/json/items?page=2，https://example.com/json/items?page=3等。
以下是我使用的代码：
MainActivity
public class MainActivity extends AppCompatActivity {
private final String TAG = "MainActivity";
private int number = 1;
//Creating a list of videos
private List<VideoItems> mVideoItemsList;
//Creating Views
private RecyclerView recyclerView;
private RecyclerView.Adapter adapter;
private RecyclerView.LayoutManager layoutManager;
private ProgressDialog mProgressDialog;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Log.d(TAG, "onCreate called");
//Initializing Views
recyclerView = (RecyclerView) findViewById(R.id.video_recycler);
LinearLayoutManager layoutManager = new LinearLayoutManager(this);
recyclerView.setLayoutManager(layoutManager);
// This method was copied from codepath (above url)
// Add the scroll listener
recyclerView.addOnScrollListener(new EndlessRecyclerViewScrollListener(layoutManager) {
@Override
public void onLoadMore(int page, int totalItemsCount) {
// Triggered only when new data needs to be appended to the list
// Add whatever code needed to append new items of the list
customLoadMoreDataFromApi(page);
}
});
//Initializing the videolist
mVideoItemsList = new ArrayList<>();
adapter = new VideoAdapter(mVideoItemsList, this);
recyclerView.setAdapter(adapter);
if (NetworkCheck.isAvailableAndConnected(this)) {
//Calling method to get data
getData();
} else {
//Codes for building Alert Dialog
alertDialogBuilder.setPositiveButton(R.string.alert_retry, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
if (!NetworkCheck.isAvailableAndConnected(mContext)) {
alertDialogBuilder.show();
} else {
getData();
}
}
});
alertDialogBuilder.setNegativeButton(R.string.alert_cancel, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
finish();
}
});
alertDialogBuilder.show();
}
}
public int getNumber() {
return number++;
}
public void setNumber(int number) {
this.number = number;
}
// This method was copied from codepath (above is url)
// Append more data into the adapter
// This method probably sends out a network request and appends new data items to your adapter;
public void customLoadMoreDataFromApi (int offset) {
// Send an API request to retrieve appropriate data using the offset value as a parameter.
// Deserialize API request and then construct new objects to append to the adapter.
// Add the new objects to the data source for adapter
mVideoItemsList.addAll(moreVideos);
// For efficiency purpose, notify the adapter of the only elements inserted that got changed
// curSize will be equal to the index of the first element inserted because the list is 0-indexed
int curSize = adapter.getItemCount();
adapter.notifyItemRangeChanged(curSize, mVideoItemsList.size() - 1);
}
//This method will get data from the web api
private void getData(){
Log.d(TAG, "getData called");
//Codes for Showing progress dialog
//Creating a json request
JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(ConfigVideo.GET_URL + getNumber(),
new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
Log.d(TAG, "onResponse called");
//Dismissing the progress dialog
if (mProgressDialog != null) {
mProgressDialog.hide();
}
//calling method to parse json array
parseData(response);
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
}
});
//Creating request queue
RequestQueue requestQueue = Volley.newRequestQueue(this);
//Adding request to the queue
requestQueue.add(jsonArrayRequest);
}
//This method will parse json data
private void parseData(JSONArray array){
Log.d(TAG, "Parsing array");
for(int i = 0; i<array.length(); i++) {
VideoItems videoItem = new VideoItems();
JSONObject jsonObject = null;
try {
jsonObject = array.getJSONObject(i);
videoItem.setVideo_title(jsonObject.getString(ConfigVideo.TAG_VIDEO_TITLE));
videoItem.setVideo_body(jsonObject.getString(ConfigVideo.TAG_VIDEO_BODY));
} catch (JSONException w) {
w.printStackTrace();
}
mVideoItemsList.add(videoItem);
}
adapter.notifyItemRangeChanged(0, adapter.getItemCount());
}
@Override
public void onDestroy() {
super.onDestroy();
Log.d(TAG, "onDestroy called");
if (mProgressDialog != null){
mProgressDialog.dismiss();
Log.d(TAG, "mProgress dialog dismissed");
}
}
}
EndlessRecyclerViewScrollListener 代码链接为EndlessRecyclerViewScrollListener。
在我的项目中，我删除了所有与GridLayoutManager和StaggeredGridLayoutManager有关的代码，因为我不需要它们。
VideoAdapter
public class VideoAdapter extends RecyclerView.Adapter<VideoAdapter.ViewHolder>{
private ImageLoader imageLoader;
private Context mContext;
//List of videos
private List<VideoItems> mVideoItems;
public VideoAdapter(List<VideoItems> videoItems, Context context) {
super();
// Getting all videos
this.mVideoItems = videoItems;
this.mContext = context;
}
@Override
public ViewHolder onCreateViewHolder (ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.video_summ, parent, false);
ViewHolder viewHolder = new ViewHolder(v);
return viewHolder;
}
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
VideoItems videoList = mVideoItems.get(position);
holder.videoTitle.setText(videoList.getVideo_title());
holder.videoBody.setText(videoList.getVideo_body());
}
@Override
public int getItemCount(){
//Return the number of items in the data set
return mVideoItems.size();
}
class ViewHolder extends RecyclerView.ViewHolder {
public NetworkImageView videoImage;
public TextView videoTitle, videoBody;
public ViewHolder (View videoView) {
super(videoView);
videoTitle = (TextView) videoView.findViewById(R.id.video_title);
videoBody = (TextView) videoView.findViewById(R.id.video_body);
}
}
}
VideoItems
public class VideoItems {
private String video_title;
private String video_body;
public String getVideo_title() {
return video_title;
}
public void setVideo_title(String video_title) {
this.video_title = video_title;
}
public String getVideo_body() {
return video_body;
}
public void setVideo_body(String video_body) {
this.video_body = video_body;
}
}
我不知道您是否可以向我提供有关如何将其实施到我的RecyclerView的提示。提前谢谢。