从使用自定义适配器的Firebase数据库检索数据到多个文本视图显示没有错误/不显示任何内容？

Question

一直试图使用自定义适配器将来自Firebase数据库的所有数据加载到四个不同的文本视图中。让它与一个textview一起工作是相当直接的。

使它与自定义适配器一起工作证明要困难得多。该代码运行，但没有任何显示在界面中，并不能显示我们的原因，因为它也不会产生任何错误。任何想法为什么这不会产生错误或不显示数据？

下面是结构：

记录型号：

public class Record { 
    public String clicked; 
    public String date; 
    public String diff; 
    public String sync; 
    public String uid; 

    public Record(){ 

    } 

    public String getClicked() { 
     return clicked; 
    } 
    public String getDate() { 
     return date; 
    } 
    public String getDiff() { 
     return diff; 
    } 
    public String getSync() { 
     return sync; 
    } 
    public String getUid() { 
     return uid; 
    } 


    public void setClicked(String clicked){ 
     this.clicked = clicked; 
    } 
    public void setDate(String date){ 
     this.date = date; 
    } 
    public void setDiff(String diff){ 
     this.diff = diff; 
    } 
    public void setSync(String time){ 
     this.sync = sync; 
    } 
    public void setUid(String uid){ 
     this.uid = uid; 
    } 

    public Record(String sync, String clicked, String diff, String date, String uid) { 
     this.clicked = clicked; 
     this.date = date; 
     this.diff = diff; 
     this.sync = sync; 
     this.uid = uid; 
    } 

CustomAdapter：

public class CustomAdapter extends BaseAdapter{ 
    Context c; 
    ArrayList<Record> records; 
    public CustomAdapter(Context c, ArrayList<Record> records) { 
     this.c = c; 
     this.records = records; 
    } 
    @Override 
    public int getCount() { 
     return records.size(); 
    } 
    @Override 
    public Object getItem(int position) { 
     return records.get(position); 
    } 
    @Override 
    public long getItemId(int position) { 
     return position; 
    } 
    @Override 
    public View getView(int position, View convertView, ViewGroup parent) { 
     if(convertView==null) 
     { 
      convertView= LayoutInflater.from(c).inflate(R.layout.list_adapter_view,parent,false); 
     } 
     TextView timeTxt= (TextView) convertView.findViewById(R.id.texttime); 
     TextView clickedTxt= (TextView) convertView.findViewById(R.id.textclick); 
     TextView diffTxt= (TextView) convertView.findViewById(R.id.textdiff); 
     TextView dateTxt= (TextView) convertView.findViewById(R.id.textdate); 


     final Record s= (Record) this.getItem(position); 
     timeTxt.setText(s.getSync()); 
     clickedTxt.setText(s.getClicked()); 
     diffTxt.setText(s.getDiff()); 
     dateTxt.setText(s.getDate()); 

     return convertView; 
    } 
} 

活动：

public class UserProfileActivity extends AppCompatActivity { 
    private FirebaseAuth mFirebaseAuth; 
    private FirebaseUser mFirebaseUser; 
    private String mUserId; 
    CustomAdapter adapter; 
    DatabaseReference db; 
    ListView lv; 
    ArrayList<Record> records = new ArrayList<>(); 

    static final ArrayList<HashMap<String,String>> list = new ArrayList<HashMap<String,String>>(); 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_user_profile2); 

     getSupportActionBar().setDisplayUseLogoEnabled(true); 
     getSupportActionBar().setDisplayShowHomeEnabled(true); 
     getSupportActionBar().setIcon(R.mipmap.ic_launcher); 

     mFirebaseAuth = FirebaseAuth.getInstance(); 
     mFirebaseUser = mFirebaseAuth.getCurrentUser(); 


     if (mFirebaseUser == null) { 
      loadLogInView(); 
     } else { 
      mUserId = mFirebaseUser.getUid(); 
      lv = (ListView) findViewById(R.id.listView); 

      db = FirebaseDatabase.getInstance().getReference().child("users").child(mUserId).child("records"); 
      adapter = new CustomAdapter(this, retrieve()); 
      lv.setAdapter(adapter); 
     } 
    } 

    public ArrayList<Record> retrieve() 
    { 
     db.addChildEventListener(new ChildEventListener() { 
      @Override 
      public void onChildAdded(DataSnapshot dataSnapshot, String s) { 
       fetchData(dataSnapshot); 
      } 
      @Override 
      public void onChildChanged(DataSnapshot dataSnapshot, String s) { 
       fetchData(dataSnapshot); 
      } 
      @Override 
      public void onChildRemoved(DataSnapshot dataSnapshot) { 
      } 
      @Override 
      public void onChildMoved(DataSnapshot dataSnapshot, String s) { 
      } 
      @Override 
      public void onCancelled(DatabaseError databaseError) { 
      } 
     }); 
     return records; 
    } 

    private void fetchData(DataSnapshot dataSnapshot) 
    { 
     for (DataSnapshot ds : dataSnapshot.getChildren()){ 

      records.clear(); 
      Record record= dataSnapshot.getValue(Record.class); 
      records.add(record); 

     } 
    } 

activity_user_profile2.xml

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 

    android:layout_width="match_parent" 
    android:layout_height="match_parent"> 

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
     android:orientation="vertical" android:layout_width="match_parent" 
     android:layout_height="match_parent" 

     android:paddingTop="5sp"> 

     <ListView 
      android:layout_width="match_parent" 
      android:layout_height="wrap_content" 
      android:id="@+id/listView" /> 
    </LinearLayout> 


</RelativeLayout> 

list_adapter_view.xml

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 

    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:orientation="horizontal" 
    android:paddingTop="5sp" 
    android:layout_alignParentLeft="true" 
    android:layout_alignParentTop="true"> 

    <TextView 
     android:textStyle="bold" 
     android:paddingTop="20sp" 
     android:textSize="20sp" 
     android:layout_weight="1" 
     android:layout_width="wrap_content" 
     android:layout_height="match_parent" 
     android:id="@+id/texttime" 
     android:layout_alignParentTop="true" 
     android:layout_alignParentStart="true"/> 

    <TextView 
     android:textStyle="bold" 
     android:paddingTop="20sp" 
     android:textSize="20sp" 
     android:layout_weight="1" 
     android:layout_width="wrap_content" 
     android:layout_height="match_parent" 
     android:id="@+id/textclick" 
     android:layout_alignParentTop="true" 
     android:layout_alignParentStart="true"/> 

    <TextView 
     android:textStyle="bold" 
     android:paddingTop="20sp" 
     android:textSize="20sp" 
     android:layout_weight="1" 
     android:layout_width="wrap_content" 
     android:layout_height="match_parent" 
     android:id="@+id/textdiff" 
     android:layout_alignParentTop="true" 
     android:layout_alignParentStart="true"/> 

    <TextView 
     android:textStyle="bold" 
     android:paddingTop="20sp" 
     android:textSize="20sp" 
     android:layout_weight="1" 
     android:layout_width="wrap_content" 
     android:layout_height="match_parent" 
     android:id="@+id/textdate" 
     android:layout_alignParentTop="true" 
     android:layout_alignParentStart="true"/> 
</LinearLayout> 

Answer 1

的问题是一对情侣在活动班线没有在正确的地方。这是工作解决方案。

public class UserProfileActivity extends AppCompatActivity { 
    private FirebaseAuth mFirebaseAuth; 
    private FirebaseUser mFirebaseUser; 

    private String mUserId; 


    CustomAdapter adapter; 
    DatabaseReference db; 
    ListView lv; 
    ArrayList<Record> records = new ArrayList<>(); 



    static final ArrayList<HashMap<String,String>> list = new ArrayList<HashMap<String,String>>(); 



    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_user_profile2); 

     getSupportActionBar().setDisplayUseLogoEnabled(true); 
     getSupportActionBar().setDisplayShowHomeEnabled(true); 
     getSupportActionBar().setIcon(R.mipmap.ic_launcher); 

     mFirebaseAuth = FirebaseAuth.getInstance(); 
     mFirebaseUser = mFirebaseAuth.getCurrentUser(); 


     if (mFirebaseUser == null) { 
      loadLogInView(); 
     } else { 
      mUserId = mFirebaseUser.getUid(); 

      lv = (ListView) findViewById(R.id.listView); 

      db = FirebaseDatabase.getInstance().getReference().child("users").child(mUserId).child("records"); 


      retrieve(); 




     } 

    } 


    public ArrayList<Record> retrieve() 
    { 


     db.addChildEventListener(new ChildEventListener() { 
      @Override 
      public void onChildAdded(DataSnapshot dataSnapshot, String s) { 
       fetchData(dataSnapshot); 
      } 
      @Override 
      public void onChildChanged(DataSnapshot dataSnapshot, String s) { 
       fetchData(dataSnapshot); 
      } 
      @Override 
      public void onChildRemoved(DataSnapshot dataSnapshot) { 
      } 
      @Override 
      public void onChildMoved(DataSnapshot dataSnapshot, String s) { 
      } 
      @Override 
      public void onCancelled(DatabaseError databaseError) { 
      } 
     }); 
     return records; 
    } 

    private void fetchData(DataSnapshot dataSnapshot) 
    { 




      Record record= dataSnapshot.getValue(Record.class); 

      records.add(record); 



     adapter = new CustomAdapter(this,records); 
     lv.setAdapter(adapter); 
    } 



    private void loadLogInView() { 
     Intent intent = new Intent(this, LoginActivity.class); 
     intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK); 
     intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK); 
     startActivity(intent); 
    } 

    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 
     getMenuInflater().inflate(R.menu.menu_main, menu); 
     return true; 
    } 

    @Override 
    public boolean onOptionsItemSelected(MenuItem item) { 

     int id = item.getItemId(); 

     if (id == R.id.action_logout) { 
      mFirebaseAuth.signOut(); 
      loadLogInView(); 
     } 

     return super.onOptionsItemSelected(item); 
    } 

}