我想从服务器加载数据并在我的应用程序 (RecyclerView) 中显示，对于这项工作，当应用程序启动时它显示 10 个帖子，当滚动 recyclerView 时显示另一个帖子。
我写了下面的代码，但是当收到其他 10 个帖子时，不显示 加载布局!我希望在获取其他 10 个帖子时，首先显示加载 布局然后显示其他 10 个帖子!
为了连接到互联网，我使用 Retrofit v2，对于 recyclerView 的自定义 Endless 方法，我使用此类: EndLess Class
我的 Activity 代码:
public class Category_page extends AppCompatActivity implements ConnectivityReceiver.ConnectivityReceiverListener {
private static final long RIPPLE_DURATION = 250;
private Toolbar toolbar;
private TextView toolbar_title;
private ImageView toolbar_menuImage;
private Button categoryCheckNet_button;
private RelativeLayout root;
private CategoryAdapter mAdapter;
private RecyclerView cat_recyclerView;
private LinearLayoutManager mLayoutManager;
private RelativeLayout loadLayout, checkNetLayout;
private String catTitle = "";
private Integer catID;
private Bundle bundle;
private int pageCount = 1;
private Context context;
private List<R_CatModel> models;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.category_page);
// Hide StatusBar color
getWindow().getDecorView().setSystemUiVisibility(
View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN);
// Initializing
context = Category_page.this;
toolbar = (Toolbar) findViewById(R.id.category_toolbar);
cat_recyclerView = (RecyclerView) findViewById(R.id.category_recycler);
toolbar_title = (TextView) toolbar.findViewById(R.id.toolbar_pages_title);
mLayoutManager = new LinearLayoutManager(this);
root = (RelativeLayout) findViewById(R.id.category_root);
loadLayout = (RelativeLayout) findViewById(R.id.category_empty_layout);
checkNetLayout = (RelativeLayout) findViewById(R.id.category_checkInternet_layout);
categoryCheckNet_button = (Button) checkNetLayout.findViewById(R.id.checkNet_button);
// Toolbar
setSupportActionBar(toolbar);
if (toolbar != null) {
getSupportActionBar().setTitle("");
}
// Receive Data
bundle = getIntent().getExtras();
catID = bundle.getInt("categoryID");
if (bundle != null) {
catTitle = bundle.getString("categoryTitle");
}
if (catTitle != null) {
toolbar_title.setText(catTitle);
}
// Load Data
loadData();
// Load Progress
loadLayout.setVisibility(View.VISIBLE);
// Menu
View guillotineMenu = LayoutInflater.from(this).inflate(R.layout.menu_layout, null);
root.addView(guillotineMenu);
toolbar_menuImage = (ImageView) toolbar.findViewById(R.id.toolbar_pages_logo);
new GuillotineAnimation.GuillotineBuilder(guillotineMenu, guillotineMenu.findViewById(R.id.menu_layout_image), toolbar_menuImage)
.setStartDelay(RIPPLE_DURATION)
.setActionBarViewForAnimation(toolbar)
.setClosedOnStart(true)
.build();
// RecyclerView
cat_recyclerView.setLayoutManager(mLayoutManager);
cat_recyclerView.setHasFixedSize(true);
cat_recyclerView.addOnScrollListener(new EndlessRecyclerOnScrollListener(mLayoutManager) {
@Override
public void onLoadMore(int current_page) {
Retrofit_ApiInterface apiInterface = Retrofit_ApiClient.getClient().create(Retrofit_ApiInterface.class);
Call<R_CatModelResponse> call = apiInterface.getCatMoreResponse(catID, current_page);
call.enqueue(new Callback<R_CatModelResponse>() {
@Override
public void onResponse(Call<R_CatModelResponse> call, Response<R_CatModelResponse> response) {
if (response != null) {
mAdapter.addNewItem(response.body().getCat_posts());
//loadLayout.setVisibility(View.GONE);
} else {
//loadLayout.setVisibility(View.VISIBLE);
Toast.makeText(Category_page.this, "Error 2", Toast.LENGTH_SHORT).show();
TastyToast.makeText(context, "خطایی رخ داده است", TastyToast.LENGTH_LONG, TastyToast.ERROR);
}
}
@Override
public void onFailure(Call<R_CatModelResponse> call, Throwable t) {
}
});
}
});
}
private void loadData() {
boolean isConnected = ConnectivityReceiver.isConnected();
retrofitData(isConnected);
}
private void retrofitData(boolean isConnect) {
if (isConnect) {
Retrofit_ApiInterface apiInterface = Retrofit_ApiClient.getClient().create(Retrofit_ApiInterface.class);
Call<R_CatModelResponse> call = apiInterface.getCatResponse(catID);
call.enqueue(new Callback<R_CatModelResponse>() {
@Override
public void onResponse(Call<R_CatModelResponse> call, Response<R_CatModelResponse> response) {
if (response != null) {
models = response.body().getCat_posts();
mAdapter = new CategoryAdapter(context, cat_recyclerView, models);
cat_recyclerView.setAdapter(mAdapter);
loadLayout.setVisibility(View.GONE);
} else {
//loadLayout.setVisibility(View.VISIBLE);
Toast.makeText(Category_page.this, "Error 2", Toast.LENGTH_SHORT).show();
TastyToast.makeText(context, "خطایی رخ داده است", TastyToast.LENGTH_LONG, TastyToast.ERROR);
}
checkNetLayout.setVisibility(View.GONE);
}
@Override
public void onFailure(Call<R_CatModelResponse> call, Throwable t) {
//loadLayout.setVisibility(View.VISIBLE);
//TastyToast.makeText(context, "لطفا برنامه را مجددا باز کنید", TastyToast.LENGTH_LONG, TastyToast.ERROR);
Toast.makeText(Category_page.this, "Error 2", Toast.LENGTH_SHORT).show();
//Cat_EmptyLayout.setVisibility(View.VISIBLE);
Log.e("CatResponseError", "Error : " + t);
}
});
} else {
//loadLayout.setVisibility(View.GONE);
checkNetLayout.setVisibility(View.VISIBLE);
if (mAdapter != null) {
mAdapter.clear();
cat_recyclerView.setAdapter(mAdapter);
}
categoryCheckNet_button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
loadData();
}
});
}
}
public void post_back(View view) {
onBackPressed();
}
@Override
protected void attachBaseContext(Context newBase) {
super.attachBaseContext(CalligraphyContextWrapper.wrap(newBase));
}
@Override
protected void onResume() {
super.onResume();
// register connection status listener
MyApplication.getInstance().setConnectivityListener(this);
}
@Override
public void onNetworkConnectionChanged(boolean isConnected) {
retrofitData(isConnected);
}
}
我的适配器代码:
public class CategoryAdapter extends RecyclerView.Adapter {
private List<R_CatModel> 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 = 10;
private int lastVisibleItem, totalItemCount;
private boolean loading;
private OnLoadMoreListener onLoadMoreListener;
public CategoryAdapter(Context context, RecyclerView recyclerView, List<R_CatModel> 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(final RecyclerView.ViewHolder holder, final int position) {
if (holder instanceof DataViewHolder) {
((DataViewHolder) holder).main_post_title.setText(Html.fromHtml(mDateSet.get(position).getTitle()));
Glide.with(mContext)
.load(mDateSet.get(position).getThumbnail_images().getMedium().getUrl())
.placeholder(R.drawable.post_image)
.crossFade()
.override(600, 350)
.into(((DataViewHolder) holder).main_post_image);
((DataViewHolder) holder).main_post_content.setText(Html.fromHtml(mDateSet.get(position).getContent()));
// Convert Date ////////
String date = mDateSet.get(position).getDate();
String[] parts = date.split(" ");
String datePart = parts[0];
String timePart = parts[1];
int year;
int month;
int day;
String[] dateParts = datePart.split("-");
year = Integer.parseInt(dateParts[0]);
month = Integer.parseInt(dateParts[1]);
day = Integer.parseInt(dateParts[2]);
JalaliCalendar.YearMonthDate georgianDate = new JalaliCalendar.YearMonthDate(year, month, day);
JalaliCalendar.YearMonthDate JalaliDate = JalaliCalendar.gregorianToJalali(georgianDate);
String jalaliDateTime = JalaliDate.toString();
((DataViewHolder) holder).main_dateTime.setText(jalaliDateTime);
////////////////////////
((DataViewHolder) holder).main_author.setText(Html.fromHtml(mDateSet.get(position).getCatAuthor().getAuthorName()));
((DataViewHolder) holder).main_author.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
R_CatModel model = mDateSet.get(position);
v.getContext().startActivity(new Intent(v.getContext(), Profile_page.class));
//.putExtra("author", model.getAuthor())
//.putExtra("authorID", model.getAuthorID())
//.putExtra("authorStatus", model.getAuthorStatus()));
}
});
((DataViewHolder) holder).main_category.setText(Html.fromHtml(String.valueOf(mDateSet.get(position).getCategories().get(0).getCatTitle())));
((DataViewHolder) holder).main_category.setTextColor(mContext.getResources().getColor(R.color.colorAccent));
((DataViewHolder) holder).main_post_image.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int pos = holder.getPosition();
R_CatModel model = mDateSet.get(pos);
v.getContext().startActivity(new Intent(v.getContext(), PostShow_page.class)
.putExtra("title", model.getTitle())
.putExtra("image", model.getThumbnail())
.putExtra("content", model.getContent())
.putExtra("dateTime", model.getDate())
//.putExtra("author", model.getAuthor())
.putExtra("category", model.getTitle()));
}
});
} 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 addNewItem(List<R_CatModel> newContent) {
int start = this.mDateSet.size();//contents is a List of your items initialize it your constructor
int end = newContent.size();
mDateSet.addAll(newContent);
notifyItemRangeInserted(start + 1, end);
}
public void add(List<R_CatModel> models) {
mDateSet.addAll(models);
notifyDataSetChanged();
}
public void update(List<R_CatModel> models) {
mDateSet.clear();
mDateSet.addAll(models);
notifyDataSetChanged();
}
public class DataViewHolder extends RecyclerView.ViewHolder {
private TextView main_post_title, main_post_content, main_dateTime, main_author, main_category;
private ImageView main_post_image;
public DataViewHolder(final 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);
main_dateTime = (TextView) itemView.findViewById(R.id.post_date_text);
main_author = (TextView) itemView.findViewById(R.id.post_name_text);
main_category = (TextView) itemView.findViewById(R.id.post_category_text);
}
}
public static class ProgressViewHolder extends RecyclerView.ViewHolder {
public AVLoadingIndicatorView progressBar;
public ProgressViewHolder(View v) {
super(v);
progressBar = (AVLoadingIndicatorView) v.findViewById(R.id.avloadingIndicatorView);
}
}
}
如何在获取其他 10 个帖子时显示加载布局？
最佳答案
让我向您解释一个解决这个问题的简单方法:
1- 将线性 progressBar 放在 RecyclerView 下方，默认可见性 gone:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/layout_container"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/gray_lightest">
<android.support.v7.widget.RecyclerView
android:id="@+id/lv_paging"
style="@style/RecycleView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="4dp"
android:paddingTop="4dp"
tools:listitem="@layout/row_list_base" />
<com.rey.material.widget.ProgressView
android:id="@+id/pvl_loading"
style="@style/LinearProgress"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:visibility="gone"
android:layout_alignParentBottom="true" />
</RelativeLayout>
2- 在您的 onLoadMore 中，将 ProgressBar 的可见性更改为 Visible:
scrollListener = new EndlessRecyclerOnScrollListener((LinearLayoutManager) mRecyclerView.getLayoutManager()) {
@Override
public void onLoadMore(int page) {
progressBar.setVisiblity(View.VISIBLE);
callWebService(page);
}
};
mRecyclerView.addOnScrollListener(scrollListener);
3- 当您的请求完成时，将可见性更改为gone:
public void onResponse(Call<YOUR_OBJECT> call, Response<YOUR_OBJECT> response) {
progressBar.setVisiblity(View.GONE);
processResponse(response);
}
替代方法:如果您想在适配器中处理进度条，请参阅完整代码 here .主要关键部分代码:
1- 添加 showLoadingView 方法到适配器:
public void showLoadingView() {
showLoadingView = true;
notifyItemChanged(0);
}
2- 将 getViewType 更改为:
@Override
public int getItemViewType(int position) {
if (showLoadingView && position == 0) {
return VIEW_TYPE_LOADER;
} else {
return VIEW_TYPE_DEFAULT;
}
}
关于android - 如何在android中无休止地向RecyclerView显示布局，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/39341697/