我在Android Studio中创建了一个RecyclerView，就像在另一个片段中一样。问题是所有的工作都是第一次看，但在创建一个行对象并说明应用程序之后，我看不到任何条目。我做过这个RecyclerView的方式和我原来的那个做得很好。我已经搜索了很多，但我可以找到错误。
这是我的片段xml：
<android.support.v4.widget.SwipeRefreshLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/training_swiperefresh"
android:layout_width="match_parent"
android:layout_height="match_parent">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="@+id/trainingtTitle"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:layout_marginTop="0dp"
android:layout_marginBottom="16dp"
android:textStyle="bold"
android:textColor="@color/colorPrimary"
android:text="@string/trainingTitle" />
<android.support.v7.widget.RecyclerView
android:id="@+id/training_recycler_view"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:scrollbars="vertical"
android:layout_below="@+id/trainingtTitle" />
</RelativeLayout>
</android.support.v4.widget.SwipeRefreshLayout>
这是RecyclerView的行布局：
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:focusable="true"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:clickable="true"
android:background="?android:attr/selectableItemBackground"
android:orientation="vertical">
<!-- Plan icon -->
<ImageView
android:id="@+id/planImage"
android:layout_width="24dp"
android:layout_height="24dp"
android:layout_centerVertical="true"
android:layout_alignParentStart="true"
android:layout_marginRight="8dp"
android:layout_marginTop="1dp"
android:layout_marginBottom="1dp"
android:contentDescription="Icon"
android:src="@drawable/ic_menu_train" />
<!-- Plan title -->
<TextView
android:id="@+id/planTitle"
android:textColor="@color/colorBlack"
android:layout_width="match_parent"
android:layout_marginLeft="40dp"
android:layout_marginRight="40dp"
android:layout_marginTop="14dp"
android:textSize="16dp"
android:layout_height="wrap_content" />
<!-- Plan type -->
<TextView
android:id="@+id/planType"
android:layout_below="@id/planTitle"
android:layout_marginLeft="40dp"
android:layout_marginRight="40dp"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<!-- Plan date -->
<TextView
android:id="@+id/planDate"
android:layout_width="match_parent"
android:layout_below="@id/planType"
android:layout_marginLeft="42dp"
android:layout_marginRight="40dp"
android:layout_marginBottom="14dp"
android:layout_height="wrap_content" />
<!-- Plan view -->
<ImageView
android:id="@+id/planView"
android:layout_width="24dp"
android:layout_height="24dp"
android:layout_alignParentEnd="true"
android:layout_centerVertical="true"
android:layout_marginTop="1dp"
android:layout_marginBottom="1dp"
android:contentDescription="Icon"
android:src="@drawable/ic_menu_show" />
<View
android:layout_width="fill_parent"
android:layout_height="1dip"
android:layout_below="@id/planDate"
android:layout_marginLeft="42dp"
android:background="#DCDCDC" />
</RelativeLayout>
这是我称之为适配器的片段：
public class TrainingFragment extends Fragment {
private OnFragmentInteractionListener mListener;
// Variables for Recycler View
private List<Plans> planList = new ArrayList<>();
private RecyclerView trainingRecyclerView;
private PlansAdapter pAdapter;
public TrainingFragment() {
// Required empty public constructor
}
//Change the title in action bar
public void onResume() {
super.onResume();
String titleString = getResources().getString(R.string.title_activity_navigation_drawer_training);
// Set title bar
((NavigationDrawerActivity) getActivity())
.setActionBarTitle(titleString);
}
public static TrainingFragment newInstance() {
TrainingFragment fragment = new TrainingFragment();
return fragment;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Menü bekannt geben, dadurch kann Fragment Menü-Events verarbeiten
setHasOptionsMenu(true);
}
//Fragment XML geben, sowie als Menü setzen
@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
inflater.inflate(R.menu.menu_training, menu);
// Declare ImageView and Animation for rotation animation
MenuItem reloadButton = (MenuItem) menu.findItem(R.id.menu_reloadbutton);
final Animation rotation = AnimationUtils.loadAnimation(getActivity(), R.anim.animation_rotate);
//if (reloadButton != null) {
// //reloadButton.setImageResource(R.drawable.ic_menu_reloadentry);
// reloadButton.getActionView().setOnClickListener(new View.OnClickListener() {
// @Override
// public void onClick(View view) {
// rotation.setRepeatCount(Animation.INFINITE);
// view.startAnimation(rotation);
// }
// });
//}
}
//AddEntry click abfangen und verarbeiten
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Wir prüfen, ob Menü-Element mit der ID "action_daten_aktualisieren"
// ausgewählt wurde und geben eine Meldung aus
int id = item.getItemId();
if (id == R.id.menu_reloadbutton) {
// Text ausgeben
//Toast.makeText(getActivity(), "Liste aktualisieren gedrückt!", Toast.LENGTH_LONG).show();
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_training, container, false);
// Get Refresh Layout
SwipeRefreshLayout swipeRefreshLayout = (SwipeRefreshLayout) view.findViewById(R.id.training_swiperefresh);
// Change color for the refresh layout
swipeRefreshLayout.setColorSchemeColors(Color.rgb(99, 195, 195));
trainingRecyclerView = (RecyclerView) view.findViewById(R.id.training_recycler_view);
pAdapter = new PlansAdapter(planList, getContext());
RecyclerView.LayoutManager pLayoutManager = new LinearLayoutManager(getActivity().getApplicationContext());
trainingRecyclerView.setLayoutManager(pLayoutManager);
trainingRecyclerView.setItemAnimator(new DefaultItemAnimator());
trainingRecyclerView.setAdapter(pAdapter);
preparePlansData();
return view;
}
private void preparePlansData() {
// Set plan data
Plans plan = new Plans("ABC-Bestellung", "Muskelaufbau", "Datum: 21.04.1997");
// Add Object to list
planList.add(plan);
plan = new Plans("test", "tttt", "ttttt");
planList.add(plan);
// Notify data changes
pAdapter.notifyDataSetChanged();
}
// TODO: Rename method, update argument and hook method into UI event
public void onButtonPressed(Uri uri) {
if (mListener != null) {
mListener.onFragmentInteraction(uri);
}
}
@Override
public void onAttach(Context context) {
super.onAttach(context);
}
@Override
public void onStart() {
super.onStart();
try {
mListener = (OnFragmentInteractionListener) getActivity();
} catch (ClassCastException e) {
throw new ClassCastException(getActivity().toString()
+ " must implement OnFragmentInteractionListener");
}
}
@Override
public void onDetach() {
super.onDetach();
mListener = null;
}
/**
* This interface must be implemented by activities that contain this
* fragment to allow an interaction in this fragment to be communicated
* to the activity and potentially other fragments contained in that
* activity.
* <p>
* See the Android Training lesson <a href=
* "http://developer.android.com/training/basics/fragments/communicating.html"
* >Communicating with Other Fragments</a> for more information.
*/
public interface OnFragmentInteractionListener {
// TODO: Update argument type and name
void onFragmentInteraction(Uri uri);
}
}
这是我的适配器：
public class PlansAdapter extends RecyclerView.Adapter<PlansAdapter.MyPlanHolder> {
private List<Plans> planList;
private final Context customContext;
public class MyPlanHolder extends RecyclerView.ViewHolder {
public TextView planTitle, planType, planDate;
public MyPlanHolder(View view) {
super(view);
planTitle = (TextView) view.findViewById(R.id.planTitle);
planType = (TextView) view.findViewById(R.id.planType);
planDate = (TextView) view.findViewById(R.id.planDate);
}
}
public PlansAdapter(List<Plans> planList, Context customContext) {
this.planList = planList;
this.customContext = customContext;
}
@Override
public MyPlanHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(parent.getContext())
.inflate(R.layout.plans_list_row, parent, false);
return new MyPlanHolder(itemView);
}
@Override
public void onBindViewHolder(MyPlanHolder holder, int position) {
final Plans plan = planList.get(position);
holder.planTitle.setText(plan.getPlanTitle());
holder.planType.setText(plan.getPlanType());
holder.planDate.setText(plan.getPlanDate());
}
@Override
public int getItemCount() {
return 0;
}
}
最后我的元素对象类：
public class Plans {
private String planTitle, planType, planDate;
public Plans(String planTitle, String planType, String planDate) {
this.planTitle = planTitle;
this.planType = planType;
this.planDate = planDate;
}
public void setPlanTitle(String planTitle) {
this.planTitle = planTitle;
}
public String getPlanTitle() {
return planTitle;
}
public void setPlanType(String planType) {
this.planType = planType;
}
public String getPlanType() {
return planType;
}
public void setPlanDate(String planDate) {
this.planDate = planDate;
}
public String getPlanDate() {
return planDate;
}
}
我希望你能找到这个问题。
答案 0 :(得分：2)
在Adapter的getItemCount（）方法中，您将返回0作为list的大小。您应该将其更改为return planList.size（）
答案 1 :(得分：1)
你的代码很好，除了在你的适配器中你在getItemCount（）方法中返回0。
这是更新后的代码：
public class PlansAdapter extends RecyclerView.Adapter<PlansAdapter.MyPlanHolder> {
private List<Plans> planList;
private final Context customContext;
public class MyPlanHolder extends RecyclerView.ViewHolder {
public TextView planTitle, planType, planDate;
public MyPlanHolder(View view) {
super(view);
planTitle = (TextView) view.findViewById(R.id.planTitle);
planType = (TextView) view.findViewById(R.id.planType);
planDate = (TextView) view.findViewById(R.id.planDate);
}
}
public PlansAdapter(List<Plans> planList, Context customContext) {
this.planList = planList;
this.customContext = customContext;
}
@Override
public MyPlanHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(parent.getContext())
.inflate(R.layout.plans_list_row, parent, false);
return new MyPlanHolder(itemView);
}
@Override
public void onBindViewHolder(MyPlanHolder holder, int position) {
final Plans plan = planList.get(position);
holder.planTitle.setText(plan.getPlanTitle());
holder.planType.setText(plan.getPlanType());
holder.planDate.setText(plan.getPlanDate());
}
@Override
public int getItemCount() {
return planList.size();
}
}