片段中的 NoSuchMethodError 与 Cardview 和 RecyclerView 连接到 Firebase

Question

我正在尝试创建一个连接到 firebase 的事件报告应用程序，每当我在应用程序中创建事件时，它都会显示在 Firebase 数据库中，并以 Cardview 和 RecyclerView 的形式显示在应用程序本身中。我的应用程序已经可以在 Firebase 中显示输出，现在我正在尝试完成 CardView 和 RecyclerView。

但是，当我现在运行我的应用程序时，每当我尝试单击允许我输入事件的片段时，应用程序就会崩溃并显示此错误：

java.lang.NoSuchMethodError：Lcom/google/firebase/FirebaseApp 类中没有虚拟方法 zzbox()Z；或其超类（“com.google.firebase.FirebaseApp”的声明出现在 /data/app/com.example.samuel.a4-CppiMKcbuMktQgH7RUO1XA==/split_lib_dependencies_apk.apk 中）

假定的错误是我片段中的这一行：

mDatabase = FirebaseDatabase.getInstance().getReference().child("Incidents");

请记住，这是在片段中，而我观看的教程是在普通课堂上。

这是我输入事件的片段

package com.example.samuel.a4;

import android.content.Intent;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;
import android.widget.Toolbar;

import com.firebase.ui.database.FirebaseRecyclerAdapter;
import com.github.clans.fab.FloatingActionButton;
import com.github.clans.fab.FloatingActionMenu;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;

import org.w3c.dom.Text;


public class IncmanFragment extends Fragment {

private RecyclerView mBlogList;
private DatabaseReference mDatabase;

FloatingActionButton fab;

@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable 
ViewGroup container, @Nullable Bundle savedInstanceState) {
//        return inflater.inflate(R.layout.fragment_incman, container, 
false);
     //i moved this up from just ontop of fab to here
    View myView = inflater.inflate(R.layout.fragment_incman, container, 
false);
   // getFragmentManager().findFragmentById(R.id.fragment_container);
    mDatabase = 
FirebaseDatabase.getInstance().getReference().child("Incidents");
    mDatabase.keepSynced(true);

    mBlogList=(RecyclerView) myView.findViewById(R.id.recyclerview);
    mBlogList.setHasFixedSize(true);
    mBlogList.setLayoutManager(new LinearLayoutManager(getActivity()));


    fab = (FloatingActionButton) myView.findViewById(R.id.fabIncident);
    fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            FragmentTransaction fragmentTransaction = 
getFragmentManager().beginTransaction();
            fragmentTransaction.replace(R.id.fragment_container, new 
ReportFragment());
            fragmentTransaction.addToBackStack(null);
          /*  Toast.makeText(getActivity(), "toast successful", 
Toast.LENGTH_SHORT).show();*/
            fragmentTransaction.commit();

        }

    });

    return myView;
}

@Override
public void onStart() {
    super.onStart();
    FirebaseRecyclerAdapter<IncmanFirebaseName, IncmanViewHolder> 
    firebaseRecyclerAdapter = new 
    FirebaseRecyclerAdapter<IncmanFirebaseName, 
    IncmanViewHolder>
            (IncmanFirebaseName.class, R.layout.incidentdesign, 
      IncmanViewHolder.class, mDatabase) {
        @Override
        protected void populateViewHolder(IncmanViewHolder viewHolder, 

            viewHolder.setTitle(model.getTitle());
            viewHolder.setDetails(model.getDetailsId());
            viewHolder.setRemarks(model.getRemarksId());
            viewHolder.setLocation(model.getLocationId());
            viewHolder.setDate(model.getDate());
            viewHolder.setUrgency(model.getUrgencyId());

        }
    };

    mBlogList.setAdapter(firebaseRecyclerAdapter);

}

    public static class IncmanViewHolder extends RecyclerView.ViewHolder
    {
        View mView;
        public IncmanViewHolder(View itemView)
        {
            super(itemView);
            mView = itemView;
        }
        public void setTitle(String title)
        {
            TextView tvtitledesign = 
    (TextView)mView.findViewById(R.id.tvtitledesign);
            tvtitledesign.setText(title);
        }
        public void setDetails(String detailsId)
        {
            TextView tvdetailsdesign = 
    (TextView)mView.findViewById(R.id.tvdetailsdesign);
            tvdetailsdesign.setText(detailsId);
        }
        public void setRemarks(String remarksId)
        {
            TextView tvremarksdesign = 
    (TextView)mView.findViewById(R.id.tvremarksdesign);
            tvremarksdesign.setText(remarksId);
        }
        public void setLocation(String locationId)
        {
            TextView tvlocationdesign = (TextView) 
    mView.findViewById(R.id.tvlocationdesign);
            tvlocationdesign.setText(locationId);

        }
        public void setDate (String date)
        {
            TextView tvdatedesign = 
     (TextView)mView.findViewById(R.id.tvdatedesign);
            tvdatedesign.setText(date);
        }
        public void setUrgency(String urgencyId)
        {
            TextView tvurgencydesign = 
     (TextView)mView.findViewById(R.id.tvurgencydesign);
            tvurgencydesign.setText(urgencyId);
        }
    }
}

这是构造函数以及get和set方法所在的类

 package com.example.samuel.a4;

    public class IncmanFirebaseName {

    private String date;
    private String detailsId;
    private String locationId;
    private String remarksId;
    private String reportedById;
    private String splocationId;
    private String typeId;
    private String urgencyId;
    private String title;

    public IncmanFirebaseName(String date, String detailsId, String 
    remarksId/*String reportedById*/ /* String typeId*/, String urgencyId, 
    String 
    title) {
        this.date = date;
        this.detailsId = detailsId;
      /*  this.locationId = locationId;*/
        this.remarksId = remarksId;
        /*this.reportedById = reportedById;*/
        this.splocationId = splocationId;
        /*this.typeId = typeId;*/
        this.urgencyId = urgencyId;
        this.title=title;
    }

    public String getDate() {
        return date;
    }

    public void setDate(String date) {
        this.date = date;
    }

    public String getDetailsId() {
        return detailsId;
    }

    public void setDetailsId(String detailsId) {
        this.detailsId = detailsId;
    }

    public String getLocationId() {
        return locationId;
    }

    public void setLocationId(String locationId) {
        this.locationId = locationId;
    }

    public String getRemarksId() {
        return remarksId;
    }

    public void setRemarksId(String remarksId) {
        this.remarksId = remarksId;
    }

    /*public String getReportedById() {
        return reportedById;
    }

    public void setReportedById(String reportedById) {
        this.reportedById = reportedById;
    }*/

    /* public String getSplocationId() {
        return splocationId;
    }

    public void setSplocationId(String splocationId) {
        this.splocationId = splocationId;
    }*/

     /*   public String getTypeId() {
        return typeId;
    }

    public void setTypeId(String typeId) {
        this.typeId = typeId;
    }*/

    public String getUrgencyId() {
        return urgencyId;
    }

    public void setUrgencyId(String urgencyId) {
        this.urgencyId = urgencyId;
    }

    public String getTitle(){
        return title;
    }
    public void setTitle() {
        this.title = title;
    }
    public IncmanFirebaseName()
    {

    }
    }

Database Structure

现在我不确定为什么 logcat 在我的代码中将该行显示为错误，因为我在另一个片段中有类似的行并且它工作得非常好；这是片段：“ package com.example.samuel.a4;

    import android.app.DatePickerDialog;
    import android.app.ProgressDialog;
    import android.content.Intent;
    import android.graphics.Bitmap;
    import android.graphics.Color;
    import android.graphics.drawable.ColorDrawable;
    import android.media.Image;
    import android.net.Uri;
    import android.os.Bundle;
    import android.provider.MediaStore;
    import android.support.annotation.NonNull;
    import android.support.annotation.Nullable;
    import android.support.v4.app.Fragment;
    import android.text.TextUtils;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.AdapterView;
    import android.widget.ArrayAdapter;
    import android.widget.Button;
    import android.widget.DatePicker;
    import android.widget.EditText;
    import android.widget.ImageView;
    import android.widget.Spinner;
    import android.widget.TextView;
    import android.widget.Toast;

    import com.google.android.gms.tasks.OnCompleteListener;
    import com.google.android.gms.tasks.OnFailureListener;
    import com.google.android.gms.tasks.OnSuccessListener;
    import com.google.android.gms.tasks.Task;
    import com.google.firebase.database.DatabaseReference;
    import com.google.firebase.database.FirebaseDatabase;
    import com.google.firebase.storage.FirebaseStorage;
    import com.google.firebase.storage.OnProgressListener;
    import com.google.firebase.storage.StorageReference;
    import com.google.firebase.storage.UploadTask;

    import org.w3c.dom.Text;

    import java.io.IOException;
    import java.util.Calendar;
    import java.util.Date;
    import java.util.UUID;

    import static android.app.Activity.RESULT_OK;

    public class ReportFragment extends Fragment implements 
    AdapterView.OnItemSelectedListener{

    private Button btnChoose,btnUpload;
    private ImageView imageView;
    private Uri filePath;
    private final int PICK_IMAGE_REQUEST = 71;
    private TextView mDisplayDate;
    private DatePickerDialog.OnDateSetListener mDateSetListener;

    private EditText reportedBy;
    private TextView date; //upstairs declare alr as mDisplayDate
    private Spinner spinner; //downstairs declare alr as spinner3
    private EditText location;
    private Spinner spinner2; //downstairs declare alr as spinner2
    private EditText details;
    private Spinner spinner3; //downstairs declare alr as spinner1
    private EditText remarks;
    private EditText title;
    private Button submitIncident;

    DatabaseReference databaseIncidents;
    FirebaseStorage storage;
    StorageReference storageReference;

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable 
    ViewGroup container, @Nullable Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.fragment_report, container, 
false);

          databaseIncidents = 
    FirebaseDatabase.getInstance().getReference("Incidents");
        storage = FirebaseStorage.getInstance();
        storageReference = storage.getReference();

        btnChoose = (Button) v.findViewById(R.id.btnChoose);
        btnUpload = (Button) v.findViewById(R.id.btnUpload);
        imageView = (ImageView) v.findViewById(R.id.imgView);

        reportedBy = (EditText) v.findViewById(R.id.etreportedby);
    //        Below have already line 151
    //        date = (TextView) v.findViewById(R.id.tvdate);
        location = (EditText) v.findViewById(R.id.etlocation);
        details = (EditText) v.findViewById(R.id.etdetails);
        remarks = (EditText) v.findViewById(R.id.etremarks);
        title = (EditText) v.findViewById(R.id.ettitle);
        submitIncident = (Button) v.findViewById(R.id.btnSubmit);


        btnChoose.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                chooseImage();
            }
        });
        btnUpload.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                uploadImage();
            }
        });

        submitIncident.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                incidentSubmit();
            }
        });

        return v;


    }

    private void incidentSubmit(){
        String reportedname = reportedBy.getText().toString().trim();
        String location1 = location.getText().toString();
        String details1 = details.getText().toString();
        String remarks1 = remarks.getText().toString();
        String urgency1 = spinner.getSelectedItem().toString();
        String type1 = spinner2.getSelectedItem().toString();
        String splocation1 = spinner3.getSelectedItem().toString();
        String date1 = mDisplayDate.getText().toString();
        String title1 = title.getText().toString();

        if(!TextUtils.isEmpty(reportedname)) {

            String incidentId = databaseIncidents.push().getKey();
            Incident incident = new 

  Incident(reportedname,location1,details1,remarks1,urgency1,type1,splocation1,date1,title1);
            databaseIncidents.child(incidentId).setValue(incident);

            Toast.makeText(getActivity(), "Incident Added", 
    Toast.LENGTH_LONG).show();
        } else {
            Toast.makeText(getActivity(), "All fields must be 
    entered",Toast.LENGTH_LONG).show();
        }

    }


    @Override
    public void onItemSelected(AdapterView<?> parent, View view, int position, 
    long id) {
        String text = parent.getItemAtPosition(position).toString();
        Toast.makeText(parent.getContext(), text, Toast.LENGTH_SHORT).show();
    }

    @Override
    public void onNothingSelected(AdapterView<?> parent) {

    }

    }

真诚感谢任何帮助。谢谢！

Answer 1

好的，从您的评论和代码来看，我认为您在设置对数据库的引用和实际检索值之间感到困惑。

下面的代码行，只是在您的 Firebase 数据库中设置了对 Incidents 子项的引用。

mDatabase = FirebaseDatabase.getInstance().getReference().child("Incidents");

要从数据库中检索值，您必须使用eventListeners，在this answer 中阅读有关eventListeners 的更多信息。

我给你一个示例代码来检索你的数据库的locationId 节点的第一个唯一ID 的值。它看起来像这样：

mDatabase.child("LR9j...").addListenerForSingleValueEvent(new ValueEventListener() {
// in the child("LR9j..") you have to put the whole first id from your image
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                String locId = dataSnapshot.child("locationId").getValue(String.class);
            }

            @Override
            public void onCancelled(DatabaseError databaseError) {
                Log.d(TAG, "onCancelled", databaseError.toException());
            }


        });

上面的代码会将第一个唯一 ID 的 locationId 的值存储在变量 locId 中。此外，您必须了解 Firebase 异步检索值，因此它只能在 eventListener 内部工作。

在this answer 中了解有关 Firebase 异步行为的更多信息。

还可以在文档中阅读有关 Firebase 的更多信息。