Java 片段中的RecyclerView-未连接适配器,跳过布局
我有一个奇怪的情况,我有一个Java 片段中的RecyclerView-未连接适配器,跳过布局,java,android,android-fragments,android-recyclerview,Java,Android,Android Fragments,Android Recyclerview,我有一个奇怪的情况,我有一个活动托管一个TabLayout/Viewpager,它根据对Firebase数据库的更改填充数据。不幸的是,RecyclerView没有被填充,我在我的logcat中收到下面的错误。我相信即使片段不在屏幕上也会被加载,这会导致RecyclerView的填充出错。这也很奇怪,因为当我旋转屏幕时,RecyclerView会填充: 12-13 21:31:40.013 12490-12490/com.troychuinard.fanpolls E/RecyclerView:
活动
托管一个TabLayout/Viewpager
,它根据对Firebase数据库的更改填充数据。不幸的是,RecyclerView
没有被填充,我在我的logcat中收到下面的错误。我相信即使片段不在屏幕上也会被加载,这会导致RecyclerView
的填充出错。这也很奇怪,因为当我旋转屏幕时,RecyclerView
会填充:
12-13 21:31:40.013 12490-12490/com.troychuinard.fanpolls E/RecyclerView: No adapter attached; skipping layout
这是我主机中的ViewPager
适配器Activity
:
public class SectionPagerAdapter extends FragmentPagerAdapter {
public SectionPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position) {
switch (position) {
case 0:
return new TrendingFragment();
case 1:
return new FollowingFragment();
case 2:
return new LiveFragment();
default:
return new TrendingFragment();
}
}
@Override
public int getCount() {
return 3;
}
@Override
public CharSequence getPageTitle(int position) {
switch (position) {
case 0:
return getResources().getString(R.string.trending_text);
case 1:
return getResources().getString(R.string.following_text);
case 2:
return getResources().getString(R.string.new_text);
default:
return getResources().getString(R.string.trending_text);
}
}
}
下面是我在LiveFragment
中初始化onCreateView()中的RecyclerView
函数的完整片段,它是表格布局中的选项卡3:
public class LiveFragment extends Fragment {
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
private RecyclerView mRecyclerview;
private DatabaseReference mBaseRef;
private DatabaseReference mPollsRef;
private LinearLayoutManager mLayoutManager;
private FirebaseRecyclerAdapter <Poll, PollHolder> mFireAdapter;
// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;
private OnFragmentInteractionListener mListener;
public LiveFragment() {
// Required empty public constructor
}
/**
* Use this factory method to create a new instance of
* this fragment using the provided parameters.
*
* @param param1 Parameter 1.
* @param param2 Parameter 2.
* @return A new instance of fragment LiveFragment.
*/
// TODO: Rename and change types and number of parameters
public static LiveFragment newInstance(String param1, String param2) {
LiveFragment fragment = new LiveFragment();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, param1);
args.putString(ARG_PARAM2, param2);
fragment.setArguments(args);
return fragment;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mBaseRef = FirebaseDatabase.getInstance().getReference();
mPollsRef = mBaseRef.child("Polls");
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
final View v = inflater.inflate(R.layout.fragment_new, container, false);
Log.v("TAG", "ON CREATE CALLED FROM NEW");
mLayoutManager = new LinearLayoutManager(getActivity());
mLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
mRecyclerview = (RecyclerView)v.findViewById(R.id.new_RecyclerView);
if (mRecyclerview != null){
mRecyclerview.setHasFixedSize(true);
}
if (mRecyclerview == null){
Log.v("TAG", "RECYCLERVIEW NULL");
} else if (mLayoutManager == null){
Log.v("TAG", "LAYOUTMANAGER NULL");
} else if (mFireAdapter == null) {
Log.v("TAG", "mFIREADAPTER NULL");
}
return v;
}
// 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 onStart() {
super.onStart();
}
@Override
public void onStop() {
super.onStop();
if (mFireAdapter != null){
mFireAdapter.cleanup();
}
}
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
mRecyclerview.setLayoutManager(mLayoutManager);
mFireAdapter = new FirebaseRecyclerAdapter<Poll, PollHolder>(Poll.class, R.layout.latest_item, PollHolder.class, mPollsRef) {
@Override
protected void populateViewHolder(PollHolder viewHolder, Poll model, int position) {
viewHolder.mPollQuestion.setText(model.getQuestion());
Picasso.with(getActivity().getApplicationContext())
.load(model.getImage_URL())
.fit()
.into(viewHolder.mPollImage);
Log.v("QUESTION", model.getQuestion());
Log.v("IMAGE", model.getImage_URL());
}
};
mRecyclerview.setAdapter(mFireAdapter);
mPollsRef.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for (DataSnapshot x : dataSnapshot.getChildren()){
mFireAdapter.notifyItemInserted(0);
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
@Override
public void onAttach(Context context) {
super.onAttach(context);
if (context instanceof OnFragmentInteractionListener) {
mListener = (OnFragmentInteractionListener) context;
} else {
throw new RuntimeException(context.toString()
+ " must implement OnFragmentInteractionListener");
}
}
@Override
public void onDetach() {
super.onDetach();
mListener = null;
}
public static class PollHolder extends RecyclerView.ViewHolder {
TextView mPollQuestion;
ImageView mPollImage;
public PollHolder(View itemView) {
super(itemView);
mPollQuestion = (TextView) itemView.findViewById(R.id.latest_item_question);
mPollImage = (ImageView) itemView.findViewById(R.id.pollThumbNailImage);
}
}
/**
* 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);
}
}
公共类LiveFragment扩展了片段{
//TODO:重命名参数参数,选择匹配的名称
//片段初始化参数,例如ARG_ITEM_NUMBER
私有静态最终字符串ARG_PARAM1=“PARAM1”;
私有静态最终字符串ARG_PARAM2=“PARAM2”;
私人回收视图mRecyclerview;
私人数据库参考mBaseRef;
私有数据库参考mPollsRef;
私人直线酒店经理;
专用FirebaseRecyclerAdapter mFireAdapter;
//TODO:重命名和更改参数类型
私有字符串mParam1;
私有字符串mParam2;
私有OnFragmentInteractionListener mListener;
公共LiveFragment(){
//必需的空公共构造函数
}
/**
*使用此工厂方法创建的新实例
*使用提供的参数创建此片段。
*
*@param param1参数1。
*@param param2参数2。
*@return一个fragment LiveFragment的新实例。
*/
//TODO:重命名和更改参数的类型和数量
公共静态LiveFragment newInstance(字符串param1,字符串param2){
LiveFragment=新的LiveFragment();
Bundle args=新Bundle();
args.putString(ARG_PARAM1,PARAM1);
args.putString(ARG_PARAM2,PARAM2);
fragment.setArguments(args);
返回片段;
}
@凌驾
创建时的公共void(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
mBaseRef=FirebaseDatabase.getInstance().getReference();
mPollsRef=mBaseRef.child(“轮询”);
如果(getArguments()!=null){
mParam1=getArguments().getString(ARG_PARAM1);
mParam2=getArguments().getString(ARG_PARAM2);
}
}
@凌驾
创建视图上的公共视图(布局、充气机、视图组容器、,
Bundle savedInstanceState){
//为该碎片膨胀布局
最终视图v=充气机充气(R.layout.fragment_new,container,false);
Log.v(“TAG”,“从NEW调用创建时”);
mLayoutManager=新的LinearLayoutManager(getActivity());
mLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
mRecyclerview=(RecyclerView)v.findViewById(R.id.new\u RecyclerView);
if(mRecyclerview!=null){
mRecyclerview.setHasFixedSize(true);
}
if(mRecyclerview==null){
Log.v(“标签”、“回收视图空”);
}else if(mLayoutManager==null){
Log.v(“TAG”、“LAYOUTMANAGER NULL”);
}else if(mFireAdapter==null){
Log.v(“TAG”、“mFIREADAPTER NULL”);
}
返回v;
}
//TODO:重命名方法、更新参数并将方法挂接到UI事件中
public void onButtonPressed(Uri){
if(mListener!=null){
onFragmentInteraction(uri);
}
}
@凌驾
public void onStart(){
super.onStart();
}
@凌驾
公共void onStop(){
super.onStop();
if(mFireAdapter!=null){
mFireAdapter.cleanup();
}
}
@凌驾
ActivityCreated上的公共无效(@Nullable Bundle savedinStateCState){
super.onActivityCreated(savedInstanceState);
mRecyclerview.setLayoutManager(mllayoutmanager);
mFireAdapter=新的FirebaseRecyclerAdapter(Poll.class、R.layout.latest_项、PollHolder.class、mPollsRef){
@凌驾
受保护的void populateViewHolder(PollHolder viewHolder、Poll模型、int位置){
viewHolder.mPollQuestion.setText(model.getQuestion());
Picasso.with(getActivity().getApplicationContext())
.load(model.getImage\u URL())
.fit()
.into(viewHolder.mpolimage);
Log.v(“QUESTION”,model.getQuestion());
Log.v(“IMAGE”,model.getImage_URL());
}
};
mRecyclerview.setAdapter(mFireAdapter);
mPollsRef.addListenerForSingleValueEvent(新值EventListener()){
@凌驾
公共void onDataChange(DataSnapshot DataSnapshot){
对于(DataSnapshot x:DataSnapshot.getChildren()){
mFireAdapter.notifyItemInserted(0);
}
}
@凌驾
已取消的公共void(DatabaseError DatabaseError){
}
});
}
@凌驾
公共void-onAttach(上下文){
super.onAttach(上下文);
if(OnFragmentInteractionListener的上下文实例){
mListener=(OnFragmentInteractionListener)上下文;
}否则{
抛出新的RuntimeException(context.toString()
+“必须实现OnFragmentInteractionListener”);
}
}
@凌驾
公共无效连接(){
super.onDetach();
mListener=null;
}
公共静态类PollHolder扩展了RecyclerView.ViewHolder{
文本视图问题;
图像视图MPOLIMAGE;
公共投票持有人(查看项目视图){
超级(项目视图);
mPollQuestion=(TextView)itemView.findViewById(R.id.latest\u item\u question);
mPollImage=(ImageView)itemView.findViewById(R.id.pollThumbNailImage);
}
}
/**
*此接口必须由包含以下内容的活动实现
*片段,以允许通信此片段中的交互
*该活动以及其中可能包含的其他片段
*活动。
*
*更多信息,请参见Android培训课程
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
//read Poll data from firebase mPollsRef for example
//.... database reference to firebase
//Query mPollsRef = databaseReference.child("pools").limitToFirst(200);
mRecyclerview.setLayoutManager(mLayoutManager);
mFireAdapter = new FirebaseRecyclerAdapter<Poll, PollHolder>(Poll.class, R.layout.latest_item, PollHolder.class, mPollsRef) {
@Override
protected void populateViewHolder(PollHolder viewHolder, Poll model, int position) {
viewHolder.mPollQuestion.setText(model.getQuestion());
Picasso.with(getActivity().getApplicationContext())
.load(model.getImage_URL())
.fit()
.into(viewHolder.mPollImage);
Log.v("QUESTION", model.getQuestion());
Log.v("IMAGE", model.getImage_URL());
}
};
mRecyclerview.setAdapter(mFireAdapter);
}
private FragmentPagerAdapter mPagerAdapter;
private ViewPager mViewPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_absence);
// Create the adapter that will return a fragment for each section
mPagerAdapter = new FragmentPagerAdapter(getSupportFragmentManager()) {
private final Fragment[] mFragments = new Fragment[] {
new MyAbsenceFragment(),
new MyAttendanceFragment(),
new AbsTypesFragment(),
new LiveFragment(),
};
private final String[] mFragmentNames = new String[] {
"Absences",
"Attendances",
"AbsTypes",
"Live"
};
@Override
public Fragment getItem(int position) {
return mFragments[position];
}
@Override
public int getCount() {
return mFragments.length;
}
@Override
public CharSequence getPageTitle(int position) {
return mFragmentNames[position];
}
};
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.container);
mViewPager.setAdapter(mPagerAdapter);