Firebase数据在我的RecyclerView中不会加载

huangapple
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英文:

Firebase data won't load in my RecyclerView

问题

  1. The screen launches but doesn't throw any errors or bugs. I just launch the blank recycler view as if it's not reading any of the Java codes, although they are in my manifest. I've tried bumping the Firebase path down to "Book," but then I receive a `can't convert object to java.lang.string` error.
  3. **Main activity**
  5. public class BarberView extends AppCompatActivity {
  6.     private ArrayList<Book> books;
  7.     private List<String> key;
  8.     private Context mContext;
  9.     private static final String TAG = "RealtimeDatabaseDemo";
  10.     private MyViewHolder adapter;
  11.     private TextView list_u, list_p, list_d, list_t, list_c;
  12.     DatabaseReference ref;
  14.     private FirebaseRecyclerOptions<Book> options;
  16.     RecyclerView recyclerView;
  18.     @Override
  19.     protected void onCreate(@Nullable Bundle savedInstanceState) {
  20.         super.onCreate(savedInstanceState);
  21.         setContentView(R.layout.barber_view);
  23.         recyclerView = findViewById(R.id.list_jobs);
  24.         recyclerView.setHasFixedSize(false);
  25.         recyclerView.setLayoutManager(new LinearLayoutManager(this));
  27.         ref = FirebaseDatabase.getInstance().getReference();
  28.         Query query = ref.child("gregs-281717");
  30.         final FirebaseRecyclerOptions<Book> options = new FirebaseRecyclerOptions.Builder<Book>()
  31.                 .setQuery(query, Book.class)
  32.                 .setLifecycleOwner(this)
  33.                 .build();
  35.         adapter = new MyViewHolder(options);
  36.         recyclerView.setAdapter(adapter);
  38.         query.addValueEventListener(new ValueEventListener() {
  39.             @Override
  40.             public void onDataChange(@NonNull DataSnapshot snapshot) {
  41.                 for (DataSnapshot mdatasnapshot : snapshot.getChildren()) {
  42.                     Book mbook = new Book();
  43.                     mbook.setTime(mdatasnapshot.getValue().toString());
  44.                     mbook.setDates(mdatasnapshot.getValue().toString());
  45.                     mbook.setPayDone(mdatasnapshot.getValue().toString());
  46.                     mbook.setCutDone(mdatasnapshot.getValue().toString());
  47.                     mbook.setUser_id(mdatasnapshot.getValue().toString());
  48.                     books.add(mbook);
  49.                 }
  50.                 adapter = new MyViewHolder(options);
  51.                 adapter.notifyDataSetChanged();
  52.             }
  54.             @Override
  55.             public void onCancelled(@NonNull DatabaseError error) {
  57.             }
  58.         });
  59.     }
  61.     @Override
  62.     public void onStart() {
  63.         super.onStart();
  64.         adapter.startListening();
  65.         adapter.notifyDataSetChanged();
  66.     }
  68.     @Override
  69.     protected void onStop() {
  70.         super.onStop();
  71.         adapter.startListening();
  72.         adapter.notifyDataSetChanged();
  73.     }
  74. }
  76. **ViewHolder**
  78. public class MyViewHolder extends FirebaseRecyclerAdapter<Book, MyViewHolder.Holder> {
  80.     public MyViewHolder(@NonNull FirebaseRecyclerOptions<Book> options) {
  81.         super(options);
  82.     }
  84.     @Override
  85.     protected void onBindViewHolder(@NonNull Holder holder, int position, @NonNull Book book) {
  86.         holder.list_u.setText(book.getUser_id());
  87.         holder.list_c.setText(book.getCutDone());
  88.         holder.list_d.setText(book.getDates());
  89.         holder.list_t.setText(book.getTime());
  90.         holder.list_p.setText(book.getPayDone());
  91.     }
  93.     @NonNull
  94.     @Override
  95.     public Holder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
  96.         View view = LayoutInflater.from(parent.getContext())
  97.                 .inflate(R.layout.list_item, parent, false);
  98.         return new Holder(view);
  99.     }
  101.     class Holder extends RecyclerView.ViewHolder {
  102.         public TextView list_u, list_p, list_d, list_t, list_c;
  104.         public Holder(@NonNull View itemView) {
  105.             super(itemView);
  106.             list_u = itemView.findViewById(R.id.list_user);
  107.             list_p = itemView.findViewById(R.id.list_price);
  108.             list_d = itemView.findViewById(R.id.list_date);
  109.             list_t = itemView.findViewById(R.id.list_time);
  110.             list_c = itemView.findViewById(R.id.list_cut);
  111.         }
  112.     }
  113. }
  115. **Model**
  117. import com.google.firebase.database.IgnoreExtraProperties;
  118. import org.jetbrains.annotations.NotNull;
  120. @IgnoreExtraProperties
  121. public class Book {
  122.     public String time;
  123.     public String dates;
  124.     public String payDone;
  125.     public String cutDone;
  126.     public String user_id;
  128.     public Book() {
  129.     }
  131.     @NotNull
  132.     @Override
  133.     public String toString() {
  134.         return "Book{" +
  135.                 "time='" + time + '\'' +
  136.                 ", dates='" + dates + '\'' +
  137.                 ", payDone='" + payDone + '\'' +
  138.                 ", cutDone='" + cutDone + '\'' +
  139.                 ", user_id='" + user_id + '\'' +
  140.                 '}';
  141.     }
  143.     public Book(String time, String dates, String cutDone, String payDone, String user_id) {
  144.         this.time = time;
  145.         this.dates = dates;
  146.         this.payDone = payDone;
  147.         this.cutDone = cutDone;
  148.         this.user_id = user_id;
  149.     }
  151.     public String getTime() {
  152.         return time;
  153.     }
  155.     public void setTime(String time) {
  156.         this.time = time;
  157.     }
  159.     public String getDates() {
  160.         return dates;
  161.     }
  163.     public void setDates(String dates) {
  164.         this.dates = dates;
  165.     }
  167.     public String getPayDone() {
  168.         return payDone;
  169.     }
  171.     public void setPayDone(String payDone) {
  172.         this.payDone = payDone;
  173.     }
  175.     public String getCutDone() {
  176.         return cutDone;
  177.     }
  179.     public void setCutDone(String cutDone) {
  180.         this.cutDone = cutDone;
  181.     }
  183.     public String getUser_id() {
  184.         return user_id;
  185.     }
  187.     public void setUser_id(String user_id) {
  188.         this.user_id = user_id;
  189.     }
  190. }
  192. **RecyelerView.xml**
  194. <?xml version="1.0" encoding="utf-8"?>
  195. <androidx.constraintlayout.widget.ConstraintLayout
  196.     xmlns:android="http://schemas.android.com/apk/res/android"
  197.     xmlns:app="http://schemas.android.com/apk/res-auto"
  198.     xmlns:tools="http://schemas.android.com/tools"
  199.     android:layout_width="match_parent"
  200.     android:layout_height="match_parent"
  201.     tools:context=".BarberView">
  203.     <androidx.recyclerview.widget.RecyclerView
  204.         android:layout_width="match_parent"
  205.         android:layout_height="match_parent"
  206.         android:id="@+id/list_jobs"/>
  207. </androidx.constraintlayout.widget.ConstraintLayout>
  209. **List.XML**
  211. <?xml version="1.0" encoding="utf-8"?>
  212. <androidx.constraintlayout.widget.ConstraintLayout
  213.     xmlns:android="http://schemas.android.com/apk/res/android"
  214.     xmlns:app="http://schemas.android.com/apk/res-auto"
  215.     xmlns:tools="http://schemas.android.com/tools"
  216.     android:layout_width="match_parent"
  217.     android:layout_height="wrap_content"
  218.     android:padding="16dp"
  219.     android:id="@+id/list_books">
  221.     <TextView
  222.         android:textColor="#000000"
  223.         android:id="@+id/list_cut"
  224.         android:layout_width="wrap_content"
  225.         android:layout_height="wrap_content"
  226.         android:text="TextView"
  227.         app:layout_constraintBottom_toBottomOf="parent"
  228.         app:layout_constraintStart_toStartOf="parent"
  229.         app:layout_constraintTop_toTopOf="parent" />
  231.     <TextView
  232.         android:id="@+id/list_price"
  233.         android:layout_width="62dp"
  234.         android:layout_height="19dp"
  235.         android:text="TextView"
  236.         android:textSize="14sp"
  237.         android:textColor="#000000"
  238.         app:layout_constraintBottom_toBottomOf="parent"
  239.         app:layout_constraintEnd_toStartOf="@+id/list_date"
  240.         app:layout_constraintStart_toEndOf="@+id/list_cut"
  241.         app:layout_constraintTop_toTopOf="parent
  243. <details>
  244. <summary>英文:</summary>
  246. The screen launches but doesn&#39;t throw any errors or bugs I just launch the blank recycler view as if it&#39;s not reading any of the java codes although they are in my manifest. I&#39;ve tried bumping the firebase path down on to &quot;Book&quot; but then I receive a `can&#39;t convert object to java.lang.string` error.
  248. **Main activity**
  249.    
  250.         
  251.     public  class BarberView extends AppCompatActivity {
  252.         private ArrayList&lt;Book&gt; books ;
  253.         private List&lt;String&gt; key;
  254.         private Context mContext;
  255.         private static final String TAG = &quot;RealtimeDatabaseDemo&quot;;
  256.         private MyViewHolder adapter;
  257.         private TextView list_u, list_p, list_d, list_t, list_c;
  258.         DatabaseReference ref;
  259.   
  261.         private FirebaseRecyclerOptions&lt;Book&gt; options;
  262.     
  263.     
  264.         /**
  265.          * Get the last 50 chat messages.
  266.          */
  267.     
  268.     
  269.         RecyclerView recyclerView;
  270.     
  271.         @Override
  272.         protected void onCreate(@Nullable Bundle savedInstanceState) {
  273.             super.onCreate ( savedInstanceState );
  274.             setContentView ( R.layout.barber_view );
  275.     
  276.             recyclerView =findViewById ( R.id.list_jobs );
  277.             recyclerView.setHasFixedSize ( false );
  278.             recyclerView.setLayoutManager ( new LinearLayoutManager ( this ) );
  279.     
  280.             ref =  FirebaseDatabase.getInstance ( ).getReference ( );
  281.             Query query = ref.child ( &quot;gregs-281717&quot; );
  282.     
  283.             final FirebaseRecyclerOptions&lt;Book&gt; options=new FirebaseRecyclerOptions.Builder&lt;Book&gt; ( )
  284.                     .setQuery ( query, Book.class )
  285.                     .setLifecycleOwner ( this )
  286.                     .build ( );
  287.     
  288.             adapter = new MyViewHolder ( options );
  289.             recyclerView.setAdapter ( adapter );
  290.     
  291.             query.addValueEventListener ( new ValueEventListener ( ) {
  292.                 @Override
  293.                 public void onDataChange(@NonNull DataSnapshot snapshot) {
  294.                     for (DataSnapshot mdatasnapshot: snapshot.getChildren()) {
  295.                         Book mbook =new Book();
  296.                         mbook.setTime( mdatasnapshot.getValue ( ).toString () );
  297.                         mbook.setDates( mdatasnapshot.getValue ( ).toString () );
  298.                         mbook.setPayDone( mdatasnapshot.getValue ( ).toString () );
  299.                         mbook.setCutDone( mdatasnapshot.getValue ( ).toString () );
  300.                         mbook.setUser_id( mdatasnapshot.getValue ( ).toString () );
  301.                         books.add(mbook);
  302.                     }
  303.                     adapter = new MyViewHolder (options );
  304.                     adapter.notifyDataSetChanged();
  305.     
  306.                     }
  307.     
  308.                 @Override
  309.                 public void onCancelled(@NonNull DatabaseError error) {
  310.     
  311.                 }
  312.             });
  313.     
  314.         }
  315.     
  316.         @Override
  317.         public void onStart() {
  318.             super.onStart ( );
  319.             adapter.startListening ();
  320.             adapter.notifyDataSetChanged();
  321.     
  322.         }
  323.     
  324.         @Override
  325.         protected void onStop() {
  326.             super.onStop ( );
  327.             adapter.startListening ();
  328.             adapter.notifyDataSetChanged();
  329.     
  330.         }
  331.     }
  336. **ViewHolder**
  339.             
  340.     
  341.     
  342.     public class MyViewHolder extends FirebaseRecyclerAdapter&lt;Book, MyViewHolder.Holder&gt; {
  343.     
  344.     
  345.         /**
  346.          * Initialize a {@link RecyclerView.Adapter} that listens to a Firebase query. See
  347.          * {@link FirebaseRecyclerOptions} for configuration options.
  348.          *
  349.          * @param options
  350.          */
  351.         public MyViewHolder(@NonNull FirebaseRecyclerOptions&lt;Book&gt; options) {
  352.             super ( options );
  353.         }
  354.     
  355.         @Override
  356.         protected void onBindViewHolder(@NonNull Holder holder, int position, @NonNull Book book) {
  357.             holder.list_u.setText ( book.getUser_id () );
  358.             holder.list_c.setText ( book.getCutDone () );
  359.             holder.list_d.setText ( book.getDates () );
  360.             holder.list_t.setText ( book.getTime () );
  361.             holder.list_p.setText ( book.getPayDone () );
  362.         }
  363.     
  364.         @NonNull
  365.         @Override
  366.         public Holder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
  367.             View view = LayoutInflater.from ( parent.getContext ( ) )
  368.                     .inflate ( R.layout.list_item, parent, false );
  369.             return new Holder ( view );
  370.         }
  371.     
  372.     
  373.         class Holder extends RecyclerView.ViewHolder{
  374.             public TextView list_u, list_p, list_d, list_t, list_c;
  375.     
  376.             public Holder(@NonNull View itemView) {
  377.               super(itemView);
  378.             list_u = itemView.findViewById ( R.id.list_user );
  379.             list_p = itemView.findViewById ( R.id.list_price );
  380.             list_d = itemView.findViewById ( R.id.list_date );
  381.             list_t = itemView.findViewById ( R.id.list_time );
  382.             list_c = itemView.findViewById ( R.id.list_cut );
  383.         }}
  384.     
  385.       }
  388. **Model**
  390.     import com.google.firebase.database.IgnoreExtraProperties;
  391.     
  392.     import org.jetbrains.annotations.NotNull;
  393.     
  394.     @IgnoreExtraProperties
  395.     
  396.     public class Book {
  397.         public String time;
  398.         public String dates;
  399.         public String payDone;
  400.         public String cutDone;
  401.         public String user_id;
  402.     
  403.         public Book() {
  404.         }
  405.     
  406.         @NotNull
  407.         @Override
  408.         public String toString() {
  409.             return &quot;Book{&quot; +
  410.                     &quot;time=&#39;&quot; + time + &#39;\&#39;&#39; +
  411.                     &quot;, dates=&#39;&quot; + dates + &#39;\&#39;&#39; +
  412.                     &quot;, payDone=&#39;&quot; + payDone + &#39;\&#39;&#39; +
  413.                     &quot;, cutDone=&#39;&quot; + cutDone + &#39;\&#39;&#39; +
  414.                     &quot;, user_id=&#39;&quot; + user_id + &#39;\&#39;&#39; +
  415.                     &#39;}&#39;;
  416.         }
  417.     
  418.         public Book(String time, String dates, String cutDone, String payDone, String user_id) {
  419.             this.time = time;
  420.             this.dates = dates;
  421.             this.payDone = payDone;
  422.             this.cutDone = cutDone;
  423.             this.user_id = user_id;
  424.         }
  425.     
  426.         public String getTime() {
  427.             return time;
  428.         }
  429.     
  430.         public void setTime(String time) {
  431.             this.time = time;
  432.         }
  433.     
  434.         public String getDates() {
  435.             return dates;
  436.         }
  437.     
  438.         public void setDates(String dates) {
  439.             this.dates = dates;
  440.         }
  441.     
  442.         public String getPayDone() {
  443.             return payDone;
  444.         }
  445.     
  446.         public void setPayDone(String payDone) {
  447.             this.payDone = payDone;
  448.         }
  449.     
  450.         public String getCutDone() {
  451.             return cutDone;
  452.         }
  453.     
  454.         public void setCutDone(String cutDone) {
  455.             this.cutDone = cutDone;
  456.         }
  457.     
  458.         public String getUser_id() {
  459.             return user_id;
  460.         }
  461.     
  462.         public void setUser_id(String user_id) {
  463.             this.user_id = user_id;
  464.         }
  465.     }
  468. **RecyelerView.xml**
  470.             
  471.     &lt;?xml version=&quot;1.0&quot; encoding=&quot;utf-8&quot;?&gt;
  472.     &lt;androidx.constraintlayout.widget.ConstraintLayout
  473.         xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
  474.         xmlns:app=&quot;http://schemas.android.com/apk/res-auto&quot;
  475.         xmlns:tools=&quot;http://schemas.android.com/tools&quot;
  476.         android:layout_width=&quot;match_parent&quot;
  477.         android:layout_height=&quot;match_parent&quot;
  478.         tools:context=&quot;.BarberView&quot;&gt;
  479.     
  480.         &lt;androidx.recyclerview.widget.RecyclerView
  481.             android:layout_width=&quot;match_parent&quot;
  482.             android:layout_height=&quot;match_parent&quot;
  483.             android:id=&quot;@+id/list_jobs&quot;/&gt;
  484.     &lt;/androidx.constraintlayout.widget.ConstraintLayout&gt;
  487. **List.XML**
  488.             
  489.     
  490.     &lt;?xml version=&quot;1.0&quot; encoding=&quot;utf-8&quot;?&gt;
  491.     &lt;androidx.constraintlayout.widget.ConstraintLayout
  492.         xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
  493.         xmlns:app=&quot;http://schemas.android.com/apk/res-auto&quot;
  494.         xmlns:tools=&quot;http://schemas.android.com/tools&quot;
  495.         android:layout_width=&quot;match_parent&quot;
  496.         android:layout_height=&quot;wrap_content&quot;
  497.         android:padding=&quot;16dp&quot;
  498.         android:id=&quot;@+id/list_books&quot;&gt;
  499.     
  500.     
  501.         &lt;TextView
  502.             android:textColor=&quot;#000000&quot;
  503.             android:id=&quot;@+id/list_cut&quot;
  504.             android:layout_width=&quot;wrap_content&quot;
  505.             android:layout_height=&quot;wrap_content&quot;
  506.             android:text=&quot;TextView&quot;
  507.             app:layout_constraintBottom_toBottomOf=&quot;parent&quot;
  508.             app:layout_constraintStart_toStartOf=&quot;parent&quot;
  509.             app:layout_constraintTop_toTopOf=&quot;parent&quot; /&gt;
  510.     
  511.         &lt;TextView
  512.             android:id=&quot;@+id/list_price&quot;
  513.             android:layout_width=&quot;62dp&quot;
  514.             android:layout_height=&quot;19dp&quot;
  515.             android:text=&quot;TextView&quot;
  516.             android:textSize=&quot;14sp&quot;
  517.             android:textColor=&quot;#000000&quot;
  518.             app:layout_constraintBottom_toBottomOf=&quot;parent&quot;
  519.             app:layout_constraintEnd_toStartOf=&quot;@+id/list_date&quot;
  520.             app:layout_constraintStart_toEndOf=&quot;@+id/list_cut&quot;
  521.             app:layout_constraintTop_toTopOf=&quot;parent&quot; /&gt;
  522.     
  523.         &lt;TextView
  524.             android:id=&quot;@+id/list_time&quot;
  525.             android:layout_width=&quot;wrap_content&quot;
  526.             android:layout_height=&quot;wrap_content&quot;
  527.             android:text=&quot;TextView&quot;
  528.             android:textColor=&quot;#000000&quot;
  529.             app:layout_constraintBottom_toBottomOf=&quot;parent&quot;
  530.             app:layout_constraintEnd_toEndOf=&quot;parent&quot;
  531.             app:layout_constraintTop_toTopOf=&quot;parent&quot;
  532.             tools:ignore=&quot;MissingConstraints&quot; /&gt;
  533.     
  534.         &lt;TextView
  535.             android:id=&quot;@+id/list_date&quot;
  536.             android:layout_width=&quot;wrap_content&quot;
  537.             android:layout_height=&quot;wrap_content&quot;
  538.             android:text=&quot;TextView&quot;
  539.             android:textColor=&quot;#000000&quot;
  540.             app:layout_constraintBottom_toBottomOf=&quot;parent&quot;
  541.             app:layout_constraintEnd_toEndOf=&quot;parent&quot;
  542.             app:layout_constraintStart_toStartOf=&quot;parent&quot;
  543.             app:layout_constraintTop_toTopOf=&quot;parent&quot; /&gt;
  544.     
  545.         &lt;TextView
  546.             android:id=&quot;@+id/list_user&quot;
  547.             android:layout_width=&quot;wrap_content&quot;
  548.             android:layout_height=&quot;wrap_content&quot;
  549.             android:text=&quot;TextView&quot;
  550.             android:textColor=&quot;#000000&quot;
  551.             app:layout_constraintBottom_toBottomOf=&quot;parent&quot;
  552.             app:layout_constraintEnd_toStartOf=&quot;@+id/list_time&quot;
  553.             app:layout_constraintStart_toEndOf=&quot;@+id/list_date&quot;
  554.             app:layout_constraintTop_toTopOf=&quot;parent&quot; /&gt;
  556.     
  557. **gregs-281717.jason Firebase realtime database**
  559.             
  560.     {
  561.       &quot;Book&quot; : {
  562.         &quot;cutDone&quot; : &quot;cut1&quot;,
  563.         &quot;dates&quot; : &quot;11/9/2020&quot;,
  564.         &quot;payDone&quot; : &quot;20.00&quot;,
  565.         &quot;time&quot; : &quot;03:36AM&quot;,
  566.         &quot;user_id&quot; : &quot;notme@badcode.com&quot;
  567.       }
  568.     }
  570. </details>
  573. # 答案1
  574. **得分**: 0
  576. 你应该在从Firebase加载数据后，在你的主活动中设置适配器，就像这样：
  578. ```java
  579. public class BarberView extends AppCompatActivity {
  580.     private ArrayList<Book> books;
  581.     private List<String> key;
  582.     private Context mContext;
  583.     private static final String TAG = "RealtimeDatabaseDemo";
  584.     private MyViewHolder adapter;
  585.     private TextView list_u, list_p, list_d, list_t, list_c;
  586.     DatabaseReference ref;
  588.     private FirebaseRecyclerOptions<Book> options;
  590.     RecyclerView recyclerView;
  592.     @Override
  593.     protected void onCreate(@Nullable Bundle savedInstanceState) {
  594.         super.onCreate(savedInstanceState);
  595.         setContentView(R.layout.barber_view);
  597.         recyclerView = findViewById(R.id.list_jobs);
  598.         recyclerView.setHasFixedSize(false);
  599.         recyclerView.setLayoutManager(new LinearLayoutManager(this));
  601.         ref = FirebaseDatabase.getInstance().getReference();
  602.         Query query = ref.child("gregs-281717");
  604.         final FirebaseRecyclerOptions<Book> options = new FirebaseRecyclerOptions.Builder<Book>()
  605.                 .setQuery(query, Book.class)
  606.                 .setLifecycleOwner(this)
  607.                 .build();
  609.         query.addValueEventListener(new ValueEventListener() {
  610.             @Override
  611.             public void onDataChange(@NonNull DataSnapshot snapshot) {
  612.                 for (DataSnapshot mdatasnapshot : snapshot.getChildren()) {
  613.                     Book mbook = new Book();
  614.                     mbook.setTime(mdatasnapshot.child("Book").getValue(true).toString());
  615.                     mbook.setDates(mdatasnapshot.getValue(true).toString());
  616.                     mbook.setPayDone(mdatasnapshot.getValue(true).toString());
  617.                     mbook.setCutDone(mdatasnapshot.getValue(true).toString());
  618.                     mbook.setUser_id(mdatasnapshot.getValue(true).toString());
  619.                 }
  620.                 adapter = new MyViewHolder(options);
  621.                 recyclerView.setAdapter(adapter);
  622.                 adapter.notifyDataSetChanged();
  623.             }
  625.             @Override
  626.             public void onCancelled(@NonNull DatabaseError error) {
  628.             }
  629.         });
  630.     }
  632.     @Override
  633.     public void onStart() {
  634.         super.onStart();
  635.         recyclerView.setAdapter(adapter);
  636.     }
  638.     @Override
  639.     protected void onStop() {
  640.         super.onStop();
  641.         recyclerView.setAdapter(adapter);
  642.     }
  643. }
英文:

You should set your adapter after loading data from firebase in your main activity

like this :-

  2. public  class BarberView extends AppCompatActivity {
  3. private ArrayList&lt;Book&gt; books ;
  4. private List&lt;String&gt; key;
  5. private Context mContext;
  6. private static final String TAG = &quot;RealtimeDatabaseDemo&quot;;
  7. private MyViewHolder adapter;
  8. private TextView list_u, list_p, list_d, list_t, list_c;
  9. DatabaseReference ref;
  10. private FirebaseRecyclerOptions&lt;Book&gt; options;
  11. /**
  12. * Get the last 50 chat messages.
  13. */
  14. RecyclerView recyclerView;
  15. @Override
  16. protected void onCreate(@Nullable Bundle savedInstanceState) {
  17. super.onCreate ( savedInstanceState );
  18. setContentView ( R.layout.barber_view );
  19. recyclerView =findViewById ( R.id.list_jobs );
  20. recyclerView.setHasFixedSize ( false );
  21. recyclerView.setLayoutManager ( new LinearLayoutManager ( this ) );
  22. ref =  FirebaseDatabase.getInstance ( ).getReference ( );
  23. Query query = ref.child ( &quot;gregs-281717&quot; );
  24. final FirebaseRecyclerOptions&lt;Book&gt; options=new FirebaseRecyclerOptions.Builder&lt;Book&gt; ( )
  25. .setQuery ( query, Book.class )
  26. .setLifecycleOwner ( this )
  27. .build ( );
  28. query.addValueEventListener ( new ValueEventListener ( ) {
  29. @Override
  30. public void onDataChange(@NonNull DataSnapshot snapshot) {
  31. for (DataSnapshot mdatasnapshot: snapshot.getChildren()) {
  32. Book mbook =new Book();
  33. mbook.setTime( mdatasnapshot.child ( &quot;Book&quot; ).getValue ( true).toString () );
  34. mbook.setDates( mdatasnapshot.getValue (true ).toString () );
  35. mbook.setPayDone( mdatasnapshot.getValue ( true).toString () );
  36. mbook.setCutDone( mdatasnapshot.getValue (true ).toString () );
  37. mbook.setUser_id( mdatasnapshot.getValue ( true).toString () );
  38. }
  39. adapter = new MyViewHolder (options );
  40. recyclerView.setAdapter(adapter);
  41. adapter.notifyDataSetChanged();
  42. }
  43. @Override
  44. public void onCancelled(@NonNull DatabaseError error) {
  45. }
  46. });
  47. }
  48. @Override
  49. public void onStart() {
  50. super.onStart ( );
  51. recyclerView.setAdapter(adapter);
  52. }
  53. @Override
  54. protected void onStop() {
  55. super.onStop ( );
  56. recyclerView.setAdapter(adapter);
  57. }
  58. }

huangapple
  • 本文由 发表于 2020年9月12日 01:42:20
  • 转载请务必保留本文链接：https://go.coder-hub.com/63851911.html
  • android
  • android-recyclerview
  • firebase
  • firebase-realtime-database
  • java
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