【发布时间】：2020-01-09 00:33:36
【问题描述】：
我一直使用Volley在recyclerview中显示数据的方法是在Oncreate方法中创建Adapter，然后在收到响应后通知使用 notifyDataSetChanged 从凌空抽射。
我尝试在 Retrofit 中使用相同的方法，但数据未显示在 Recyclerview 中，但如果我在改造后设置 Adapter 而不是在 Oncreate 方法中设置适配器收到 Retrofit 的响应，然后它就可以正常工作了
我的问题是
(1) 如果我在 Oncreate 中创建适配器，为什么数据没有显示在 Retrofit 中是我做错了什么吗？
(2)在Oncreate中创建适配器然后在收到响应后通知它是一种好方法吗？还是应该在收到响应后设置适配器？
如果我在收到这样的响应后设置适配器
@Override
public void onResponse(Call<SubCatModelList> call, Response<SubCatModelList> response) {
Log.d("subcategoryJsonResponse", String.valueOf(response));
Gson gson = new Gson();
String successResponse = gson.toJson(response.body());
Log.d("aaaaaa", String.valueOf(successResponse));
if (response.isSuccessful()) {
subCatModel =response.body().getSubCategories();
Log.d("asaaaaaaa", String.valueOf(subCatModel));
subCategoryAdapter = new SubCategoryAdapter(BinaryCommissionActivity.this, subCatModel);
FixedGridLayoutManager manager = new FixedGridLayoutManager();
manager.setTotalColumnCount(1);
rvBinaryCommission.setLayoutManager(manager);
rvBinaryCommission.setAdapter(subCategoryAdapter);
rvBinaryCommission.addItemDecoration(new DividerItemDecoration(BinaryCommissionActivity.this, DividerItemDecoration.VERTICAL));
}
然后每次这个行初始化适配器并在 api 命中时创建对象，我认为这是一个不好的方法
subCategoryAdapter = 新 SubCategoryAdapter(BinaryCommissionActivity.this, subCatModel);
public class BinaryCommissionActivity extends AppCompatActivity {
int scrollX = 0;
List<SubCatModel> subCatModel = new ArrayList<>();
SubCategoryAdapter subCategoryAdapter;
VolleyCustomClass volleyCustomClass;
@BindView(R.id.toolbarcustom) Toolbar toolbarcustom;
@BindView(R.id.spinner_binary_commission) Spinner spinnerBinaryCommission;
@BindView(R.id.searchViewBinary) SearchView searchViewBinary;
@BindView(R.id.headerScroll) HorizontalScrollView headerScroll;
@BindView(R.id.rvBinaryCommission) RecyclerView rvBinaryCommission;
@BindView(R.id.swipeRefreshBinaryList) SwipeRefreshLayout swipeRefreshBinaryList;
private AlertDialog dialog;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_binary_commission);
ButterKnife.bind(this);
toolbarcustom = findViewById(R.id.toolbarcustom);
setSupportActionBar(toolbarcustom);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setTitle("Binary Commission");
volleyCustomClass = new VolleyCustomClass(getApplicationContext());
dialog = new SpotsDialog.Builder().setContext(this)
.setMessage("Loading...")
.setCancelable(false).build();
spinnerData();
setUpRecyclerView();
prepareClubData();
recyclerviewScrollListener();
searchFilter();
swipeRefreshBinaryList.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
@Override
public void onRefresh() {
if (!InternetUtils.checkForInternet(getApplicationContext())) {
swipeRefreshBinaryList.setRefreshing(false);
FancyToast.makeText(getApplicationContext(), "No Internet Connection", FancyToast.LENGTH_LONG, FancyToast.ERROR, false).show();
} else {
prepareClubData();
}
}
});
}
@Override
public boolean onSupportNavigateUp() {
onBackPressed();
return super.onSupportNavigateUp();
}
/**
* Recyclerview ScrollListener
*/
private void recyclerviewScrollListener() {
rvBinaryCommission.addOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
scrollX += dx;
headerScroll.scrollTo(scrollX, 0);
}
@Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
}
});
}
/**
* Search Filter
*/
private void searchFilter() {
searchViewBinary.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
@Override
public boolean onQueryTextSubmit(String query) {
subCategoryAdapter.getFilter().filter(query);
return false;
}
@Override
public boolean onQueryTextChange(String newText) {
subCategoryAdapter.getFilter().filter(newText);
return false;
}
});
}
/**
* Adding data to spinner
*/
private void spinnerData() {
List<String> show_entries = new ArrayList<String>();
show_entries.add("5");
show_entries.add("10");
show_entries.add("15");
show_entries.add("20");
show_entries.add("All");
ArrayAdapter<String> dataAdapterShowEntries = new ArrayAdapter<String>(this,
android.R.layout.simple_spinner_item, show_entries);
dataAdapterShowEntries.setDropDownViewResource(R.layout.layout_spinner_item);
spinnerBinaryCommission.setAdapter(dataAdapterShowEntries);
spinnerBinaryCommission.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> adapterView, View view, int position, long id) {
Object item = adapterView.getItemAtPosition(position);
if (item != null) {
// Toast.makeText(getContext(), item.toString(), Toast.LENGTH_SHORT).show();
}
// Toast.makeText(getContext(), "Selected", Toast.LENGTH_SHORT).show();
}
@Override
public void onNothingSelected(AdapterView<?> adapterView) {
// TODO Auto-generated method stub
}
});
}
private void prepareClubData() {
if (!InternetUtils.checkForInternet(getApplicationContext())) {
FancyToast.makeText(getApplicationContext(), "No Internet Connection", FancyToast.LENGTH_LONG, FancyToast.ERROR, false).show();
return;
} else {
dialog.show();
if (subCatModel != null) {
subCatModel.clear();
}
/**
* Volley
*/
/* volleyCustomClass.callGetServer(URLs.subcategoryURL, new VolleyCallback() {
@Override
public void onSuccess(String response) {
Log.d("subcategoryJsonResponse", response);
try {
JSONObject obj = new JSONObject(response);
JSONArray productArray = obj.getJSONArray("sub-categories");
for (int i = 0; i < productArray.length(); i++) {
JSONObject productObject = productArray.getJSONObject(i);
SubCatModel subCatModelClass = new SubCatModel();
subCatModelClass.setSubcategoriesId(productObject.getString("Subcategories-Id"));
subCatModelClass.setCategoriesId(productObject.getString("categories-Id"));
subCatModelClass.setSubcategoriesName(productObject.getString("Subcategories-Name"));
subCatModel.add(subCatModelClass);
Log.d("subCategoryArraylist", String.valueOf(subCatModel));
}
dialog.dismiss();
subCategoryAdapter.notifyDataSetChanged();
swipeRefreshBinaryList.setRefreshing(false);
} catch (JSONException e) {
e.printStackTrace();
dialog.dismiss();
}
}
@Override
public void onError(VolleyError error) {
VolleyLog.e("Error: ", error.getMessage());
swipeRefreshBinaryList.setRefreshing(false);
}
});*/
/**
* Retrofit
*/
ApiInterface apiService = ApiClient.getClient().create(ApiInterface.class);
Call<SubCatModelList> call = apiService.getList();
call.enqueue(new Callback<SubCatModelList>() {
@Override
public void onResponse(Call<SubCatModelList> call, Response<SubCatModelList> response) {
Log.d("subcategoryJsonResponse", String.valueOf(response));
Gson gson = new Gson();
String successResponse = gson.toJson(response.body());
Log.d("aaaaaa", String.valueOf(successResponse));
if (response.isSuccessful()) {
subCatModel =response.body().getSubCategories();
Log.d("asaaaaaaa", String.valueOf(subCatModel));
}
dialog.dismiss();
subCategoryAdapter.notifyDataSetChanged();
swipeRefreshBinaryList.setRefreshing(false);
}
@Override
public void onFailure(Call<SubCatModelList> call, Throwable t) {
swipeRefreshBinaryList.setRefreshing(false);
}
});
}
}
/**
* Handles RecyclerView for the action
*/
private void setUpRecyclerView() {
subCategoryAdapter = new SubCategoryAdapter(BinaryCommissionActivity.this, subCatModel);
FixedGridLayoutManager manager = new FixedGridLayoutManager();
manager.setTotalColumnCount(1);
rvBinaryCommission.setLayoutManager(manager);
rvBinaryCommission.setAdapter(subCategoryAdapter);
rvBinaryCommission.addItemDecoration(new DividerItemDecoration(BinaryCommissionActivity.this, DividerItemDecoration.VERTICAL));
}
}
【问题讨论】：
-
subCatModel =response.body().getSubCategories();- 这并没有更新subCatModel最初指向的ArrayList，而是您传递给Adapter。那只是将subCatModel指向不同的List；Adapter没有参考的一个。也许你打算改用subCatModel.addAll(response.body().getSubCategories());。
标签： android retrofit android-volley adapter