问题
I want develop android application for one website. I read website posts from json and show its in RecyclerView every 10 posts and when user scrolling on RecyclerView show more 10 post and go to end! in this project i use okHTTP v3 and RecyclerView!
I want gonna put a button and when click on this button, load new data (if there was new data).
Button codes:
// Refresh Data
toolbar_refresh.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
LoadData();
}
});
}
Main Activity codes:
public class Main_page extends AppCompatActivity {
private static final long RIPPLE_DURATION = 250;
private Toolbar toolbar;
private RelativeLayout root;
private ImageView menu_image, toolbar_refresh;
private RecyclerView main_recyclerView;
private MainAdapter_loadMore mAdaper;
private List<MainDataModel> dataModels = new ArrayList<MainDataModel>();
protected Handler handler;
private RelativeLayout loadLayout;
private LinearLayoutManager mLayoutManager;
private int pageCount = 1;
String ServerAddress = ServerIP.getIP();
private Context context;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_page);
if (!EventBus.getDefault().isRegistered(this)) {
EventBus.getDefault().register(this);
}
// Init
handler = new Handler();
context = getApplicationContext();
toolbar = (Toolbar) findViewById(R.id.main_toolbar);
mLayoutManager = new LinearLayoutManager(this);
loadLayout = (RelativeLayout) findViewById(R.id.main_empty_layout);
toolbar_refresh = (ImageView) toolbar.findViewById(R.id.toolbar_update);
// Toolbar
if (toolbar != null) {
setSupportActionBar(toolbar);
getSupportActionBar().setTitle(null);
}
// Load First Data
LoadData();
// Menu
root = (RelativeLayout) findViewById(R.id.main_root);
View guillotineMenu = LayoutInflater.from(this).inflate(R.layout.menu_layout, null);
root.addView(guillotineMenu);
menu_image = (ImageView) toolbar.findViewById(R.id.toolbar_logo);
new GuillotineAnimation.GuillotineBuilder(guillotineMenu, guillotineMenu.findViewById(R.id.menu_layout_image), menu_image)
.setStartDelay(RIPPLE_DURATION)
.setActionBarViewForAnimation(toolbar)
.setClosedOnStart(true)
.build();
// RecyclerView and setData
main_recyclerView = (RecyclerView) findViewById(R.id.main_recycler);
main_recyclerView.setHasFixedSize(true);
main_recyclerView.setLayoutManager(mLayoutManager);
mAdaper = new MainAdapter_loadMore(this, main_recyclerView, dataModels);
main_recyclerView.setAdapter(mAdaper);
// Load More data
mAdaper.setOnLoadMoreListener(new OnLoadMoreListener() {
@Override
public void onLoadMore() {
dataModels.add(null);
mAdaper.notifyItemInserted(dataModels.size() - 1);
LoadMoreData(pageCount);
}
});
// Refresh Data
toolbar_refresh.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
LoadData();
}
});
}
@Subscribe
public void onEvent(List<MainDataModel> mainInfoModels) {
if (dataModels.size() > 0) {
dataModels.remove(dataModels.size() - 1);
mAdaper.notifyItemRemoved(dataModels.size());
mAdaper.setLoaded();
}
mAdaper.add(mainInfoModels);
mAdaper.notifyDataSetChanged();
pageCount++;
if (dataModels.isEmpty()) {
main_recyclerView.setVisibility(View.GONE);
loadLayout.setVisibility(View.VISIBLE);
} else {
main_recyclerView.setVisibility(View.VISIBLE);
loadLayout.setVisibility(View.GONE);
}
}
private void LoadData() {
MainDataInfo dataInfo = new MainDataInfo();
// here getMainDataInfo() should return the server response
dataInfo.getMainDataInfo(this);
}
private void LoadMoreData(int pageNumber) {
MainDataInfo_loadMore dataInfo_loadMore = new MainDataInfo_loadMore();
// here getMainDataInfo() should return the server response
dataInfo_loadMore.getMainDataInfo_loadMore(this, pageNumber);
}
}
Adapter codes:
public class MainAdapter_loadMore extends RecyclerView.Adapter {
private List<MainDataModel> mDateSet;
private Context mContext;
private final int VIEW_ITEM = 1;
private final int VIEW_PROG = 0;
// The minimum amount of items to have below your current scroll position
// before loading more.
private int visibleThreshold = 5;
private int lastVisibleItem, totalItemCount;
private boolean loading;
private OnLoadMoreListener onLoadMoreListener;
public MainAdapter_loadMore(Context context, RecyclerView recyclerView, List<MainDataModel> dataSet) {
this.mContext = context;
this.mDateSet = dataSet;
if (recyclerView.getLayoutManager() instanceof LinearLayoutManager) {
final LinearLayoutManager linearLayoutManager = (LinearLayoutManager) recyclerView
.getLayoutManager();
recyclerView
.addOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrolled(RecyclerView recyclerView,
int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
totalItemCount = linearLayoutManager.getItemCount();
lastVisibleItem = linearLayoutManager
.findLastVisibleItemPosition();
if (!loading
&& totalItemCount <= (lastVisibleItem + visibleThreshold)) {
// End has been reached
// Do something
if (onLoadMoreListener != null) {
onLoadMoreListener.onLoadMore();
}
loading = true;
}
}
});
}
}
@Override
public int getItemViewType(int position) {
return mDateSet.get(position) != null ? VIEW_ITEM : VIEW_PROG;
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
RecyclerView.ViewHolder vh;
if (viewType == VIEW_ITEM) {
View v = LayoutInflater.from(parent.getContext()).inflate(
R.layout.post_card_layout, parent, false);
vh = new DataViewHolder(v);
} else {
View v = LayoutInflater.from(parent.getContext()).inflate(
R.layout.progressbar_item, parent, false);
vh = new ProgressViewHolder(v);
}
return vh;
}
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
if (holder instanceof DataViewHolder) {
((DataViewHolder) holder).main_post_title.setText(mDateSet.get(position).getTitle());
Glide.with(mContext)
.load(mDateSet.get(position).getThumbnail())
.placeholder(R.drawable.post_image)
.crossFade()
.into(((DataViewHolder) holder).main_post_image);
((DataViewHolder) holder).main_post_content.setText(Html.fromHtml(mDateSet.get(position).getContent()));
} else {
((ProgressViewHolder) holder).progressBar.setVisibility(View.VISIBLE);
}
}
public void setLoaded() {
loading = false;
}
@Override
public int getItemCount() {
return mDateSet.size();
}
public void setOnLoadMoreListener(OnLoadMoreListener onLoadMoreListener) {
this.onLoadMoreListener = onLoadMoreListener;
}
public void remove(int position) {
mDateSet.remove(position);
notifyItemRemoved(position);
}
public void clear() {
mDateSet.clear();
notifyDataSetChanged();
}
public void add(List<MainDataModel> models) {
mDateSet.addAll(models);
notifyDataSetChanged();
}
public void update(List<MainDataModel> models) {
mDateSet.clear();
mDateSet.addAll(models);
notifyDataSetChanged();
}
public class DataViewHolder extends RecyclerView.ViewHolder {
private TextView main_post_title, main_post_content;
private ImageView main_post_image;
public DataViewHolder(View itemView) {
super(itemView);
main_post_title = (TextView) itemView.findViewById(R.id.post_content_title);
main_post_image = (ImageView) itemView.findViewById(R.id.post_picture_image);
main_post_content = (TextView) itemView.findViewById(R.id.post_content_text);
}
}
public static class ProgressViewHolder extends RecyclerView.ViewHolder {
public AVLoadingIndicatorView progressBar;
public ProgressViewHolder(View v) {
super(v);
progressBar = (AVLoadingIndicatorView) v.findViewById(R.id.avloadingIndicatorView);
}
}
}
AsyncTask code (LoadData codes) :
public class MainDataInfo {
private Context mContext;
private String ServerAddress = ServerIP.getIP();
public void getMainDataInfo(Context context) {
mContext = context;
new getInfo().execute(ServerAddress + "page=1");
}
private class getInfo extends AsyncTask<String, Void, String> {
EventBus bus = EventBus.getDefault();
private String ou_response;
private List<MainDataModel> infoModels;
@Override
protected void onPreExecute() {
CustomProcessDialog.createAndShow(mContext);
infoModels = new ArrayList<>();
}
@Override
protected String doInBackground(String... params) {
OkHttpClient client = new OkHttpClient();
//String url = (String) params[0];
Request request = new Request.Builder()
.url(ServerAddress + "page=1")
.cacheControl(CacheControl.FORCE_NETWORK)
.build();
Response response;
try {
response = client.newCall(request).execute();
ou_response = response.body().string();
response.body().close();
if (ou_response != null) {
try {
JSONObject postObj = new JSONObject(ou_response);
JSONArray postsArray = postObj.optJSONArray("posts");
infoModels = new ArrayList<>();
for (int i = 0; i <= infoModels.size(); i++) {
JSONObject postObject = (JSONObject) postsArray.get(i);
JSONObject images = postObject.optJSONObject("thumbnail_images");
JSONObject imagesPair = images.optJSONObject("medium");
int id = postObject.getInt("id");
String title = postObject.getString("title");
String content = postObject.getString("content");
String thumbnail = imagesPair.getString("url");
Log.d("Data", "Post id: " + id);
Log.d("Data", "Post title: " + title);
Log.d("Data", "Post title: " + thumbnail);
//Use the title and id as per your requirement
infoModels.add(new MainDataModel(id, title, content, thumbnail));
}
} catch (JSONException e) {
e.printStackTrace();
}
}
} catch (IOException e) {
e.printStackTrace();
}
return ou_response;
}
@Override
protected void onPostExecute(String result) {
CustomProcessDialog.dissmis();
if (result != null) {
bus.post(infoModels);
}
}
}
}
When use this method LoadData(); in button action, not load new data just copy fist 10 post and load again this first 10 post!
How can i fix it and when click on Button click action, load new data ?
Attention : Please don't give me negative points, help me and i really need you helps! thanks all <3
回答1:
Add this in your MainDataInfo class:
public class MainDataInfo {
private MainDataListener mListener;
public interface MainDataListener {
void onDataReceived(List<MainDataModel> infoModels);
}
public void setDataListener(MainDataListener listener){
this.mListener = listener;
}
@Override
protected void onPostExecute(String result) {
CustomProcessDialog.dissmis();
if (result != null) {
bus.post(infoModels);
//add this
if(mListener !=null)
mListener.onDataReceived(infoModels);
}
}
}
In your activity Main_page:
//implement the maindata listener
public class Main_page extends AppCompatActivity implement MainDataInfo.MainDataListener { }
Override the interface's method in the activity class
@Override
void onDataReceived(List<MainDataModel> infoModels){
// here set your recyclerview adapter
mAdaper.update(infoModels);
mAdaper.notifyDataSetChanged();
}
来源：https://stackoverflow.com/questions/36915345/load-new-data-when-refresh-recyclerview