我想在我的应用程序中使用RecyclerView。我正在跟踪并尝试改编开发者网站上的代码。这里。
Tutorial
我无法锻炼在Adapter中设置行布局的方式。我将在下面的代码中发布以下代码：
TextView startDate = (TextView) LayoutInflater.from(parent.getContext())
.inflate(R.layout.get_rota_row_layout, parent, false);
。
给了我以下例外：
> java.lang.ClassCastException: android.widget.LinearLayout cannot be
> cast to android.widget.TextView
> at
> loneworker.carefreegroup.com.loneworker.LoneworkerGetRotaActivityFragment$MyAdapter.onCreateViewHolder(LoneworkerGetRotaActivityFragment.java:161)
> at
> loneworker.carefreegroup.com.loneworker.LoneworkerGetRotaActivityFragment$MyAdapter.onCreateViewHolder(LoneworkerGetRotaActivityFragment.java:135)
> at
> android.support.v7.widget.RecyclerView$Adapter.createViewHolder(RecyclerView.java:6073)
> at
> android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5243)
> at
> android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5153)
> at
> android.support.v7.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2061)
> at
> android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1445)
> at
> android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1408)
> at
> android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:580)
> at
> android.support.v7.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:3374)
> at
> android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:3183)
> at
> android.support.v7.widget.RecyclerView.onLayout(RecyclerView.java:3627)
> at android.view.View.layout(View.java:18799)
。
我以前用过ListViews和recyclerViews，但我以前没有这样做过。在Android开发人员网站上的上述教程中，我看不到cardView的设置位置。
。
public class ActivityFragment extends Fragment {
private static final String TAG = LoneworkerGetRotaActivityFragment.class.getSimpleName();
AppObj appObj;
List<Visit> mVisitList;
String URL;
String companyID;
String ID2;
String userID;
private RecyclerView mRecyclerView;
private RecyclerView.Adapter mAdapter;
private RecyclerView.LayoutManager mLayoutManager;
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
appObj = (AppObj)getActivity().getApplication();
URL = appObj.dbModel.getCompanyUrl();
Log.e(TAG, "URL = " + URL);
companyID = appObj.dbModel.getCompanyID();
ID2 = appObj.dbModel.getCompanyWebServiceGuid();
userID = appObj.dbModel.getUserID();
}//end of onCreate
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
LayoutInflater lf = getActivity().getLayoutInflater();
View view = lf.inflate(R.layout.l_w_get_rota_activity_fragment, container, false);
mRecyclerView = (RecyclerView) view.findViewById(R.id.get_rota_recycler_view);
sendRequest();
return view;
}
private void sendRequest(){
//https://CFTest.carefreeapp.co.uk/roadrunner.asmx/GetRotaHours?CarerID=36&RotaDate=2-Nov-2017
//https://CFTest.carefreeapp.co.uk/roadrunner.asmx/RRGetRota?ID1=900&ID2=9d817606-9194-4528-84b4-028e5aa90330&CarerID=36&RotaDate=2-Nov-2017
StringRequest stringRequest = new StringRequest(URL + "/roadrunner.asmx/RRGetRota?ID1=" + companyID + "&ID2=" + ID2 + "&CarerID=" + userID + "&RotaDate=" + "2-Nov-2017",
new Response.Listener<String>() {
@Override
public void onResponse(String response) {
//success - parse rota
DomParser dp = new DomParser(getActivity());
mVisitList = dp.parseUserRota(response);
Log.e(TAG, "mVisitList has size of " + mVisitList.size());
// use this setting to improve performance if you know that changes
// in content do not change the layout size of the RecyclerView
mRecyclerView.setHasFixedSize(true);
// use a linear layout manager
mLayoutManager = new LinearLayoutManager(getActivity());
mRecyclerView.setLayoutManager(mLayoutManager);
// specify an adapter (see also next example)
mAdapter = new MyAdapter(mVisitList);
mRecyclerView.setAdapter(mAdapter);
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(getActivity(), error.getMessage(), Toast.LENGTH_LONG).show();
}
});
RequestQueue requestQueue = Volley.newRequestQueue(getActivity());
requestQueue.add(stringRequest);
}
public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> {
// Provide a reference to the views for each data item
// Complex data items may need more than one view per item, and
// you provide access to all the views for a data item in a view holder
public class ViewHolder extends RecyclerView.ViewHolder {
// each data item is just a string in this case
public TextView tvStartDate;
public ViewHolder(TextView v) {
super(v);
tvStartDate = v;
}
}
// Provide a suitable constructor (depends on the kind of dataset)
public MyAdapter(List<Visit> myVisitList) {
mVisitList = myVisitList;
}
// Create new views (invoked by the layout manager)
@Override
public MyAdapter.ViewHolder onCreateViewHolder(ViewGroup parent,
int viewType) {
// create a new view
TextView startDate = (TextView) LayoutInflater.from(parent.getContext())
.inflate(R.layout.get_rota_row_layout, parent, false);
// set the view's size, margins, paddings and layout parameters
ViewHolder vh = new ViewHolder(startDate);
return vh;
}
// Replace the contents of a view (invoked by the layout manager)
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
// - get element from your dataset at this position
// - replace the contents of the view with that element
holder.tvStartDate.setText(mVisitList.get(position).getStartDate());
}
// Return the size of your dataset (invoked by the layout manager)
@Override
public int getItemCount() {
return mVisitList.size();
}
}
}//end of class
。
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:card_view="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<!-- A CardView that contains a TextView -->
<android.support.v7.widget.CardView
xmlns:card_view="http://schemas.android.com/apk/res-auto"
android:id="@+id/card_view"
android:layout_gravity="center"
android:layout_width="match_parent"
android:layout_height="match_parent"
card_view:cardCornerRadius="4dp">
<TextView
android:id="@+id/get_rota_startdate"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</android.support.v7.widget.CardView>
</LinearLayout>
。
<?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:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
>
<android.support.v7.widget.RecyclerView
android:id="@+id/get_rota_recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scrollbars="vertical" />
</RelativeLayout>
最佳答案
像这样尝试
onCreateViewHolder(ViewGroup parent, int viewType) {
// create a new view
View startDate = LayoutInflater.from(parent.getContext())
.inflate(R.layout.get_rota_row_layout, parent, false);
return new ViewHolder(startDate);
}
public class ViewHolder extends RecyclerView.ViewHolder {
// each data item is just a string in this case
public TextView tvStartDate;
public ViewHolder(View v) {
super(v);
tvStartDate = v.findViewById(R.id.textview);
}
}
ViewHolder就像是具有所有视图的整行。在onBindViewHolder()中，您可以使用所有已经初始化的视图持有者视图