我希望从服务器加载数据并显示到我的应用程序（RecyclerView），这个作业在启动应用程序时显示10个帖子，滚动recyclerView时显示另一个帖子。
我写下面的代码但是当得到10个帖子没有加载其他帖子并显示强制关闭错误！
要连接到互联网，我使用 Retrofit v2 ，对于Endless的自定义recyclerView方法我使用此类：EndLess Class
LogCat错误：
FATAL EXCEPTION: main
Process: com.tellfa.colony, PID: 25304
java.lang.ClassCastException: com.tellfa.colony.Retrofit.Model.Category.R_CatModelResponse cannot be cast to java.util.List
at com.tellfa.colony.Activities.Category_page$1$1.onResponse(Category_page.java:124)
at retrofit2.ExecutorCallAdapterFactory$ExecutorCallbackCall$1$1.run(ExecutorCallAdapterFactory.java:68)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5349)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:908)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:703)
Api接口代码：
public interface Retrofit_ApiInterface {
// For load more category
@GET("?json=get_category_posts")
Call<R_CatModelResponse> getCatMoreResponse(@Query("id") Integer id, @Query("page") Integer page);
}
适配器代码：（我将此代码添加到我的适配器中，以便加载更多数据）
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);
}
活动代码：
@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);
// 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((List<R_CatModel>) response.body());
//loadLayout.setVisibility(View.GONE);
} else {
//loadLayout.setVisibility(View.VISIBLE);
Toast.makeText(Category_page.this, "Error 2", Toast.LENGTH_SHORT).show();
TastyToast.makeText(context, "خطايي 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, "خطايي 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 کنيد", 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();
}
});
}
}
}
如何解决此问题并在上面的代码中设置recyclerView中的 loadMore 数据？请帮助我亲爱的朋友。我真的需要你的帮助＆lt; 3
答案 0 :(得分：0)
问题是response.body()是一个R_CatModelResponse对象，但您要将其投射到List<R_CatModel>。
如果R_CatModelResponse有一个方法以R_CatModel列表回复（例如getCatModelList()），那么你只需要使用它：
mAdapter.addNewItem(response.body().getCatModelList());