Question

我正在尝试从Firebase数据库中检索数据，并使用片段在我的时间轴上显示数据。它没有显示错误，但是当我运行应用程序时，它崩溃了

我尝试评论这一点[mInterestList.setAdapter(firebaseRecyclerAdapter); ]它没有崩溃工作

public class TimeLineFragment extends Fragment {

private DatabaseReference mDatabase;

private RecyclerView mInterestList;



@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {


    mDatabase = FirebaseDatabase.getInstance().getReference().child("Interest");
    View rootView = inflater.inflate(R.layout.fragment_timeline, container, false);
    mInterestList = (RecyclerView) rootView.findViewById(R.id.interest_list);
    mInterestList.setHasFixedSize(true);
    mInterestList.setLayoutManager(new LinearLayoutManager(getActivity()));

    return rootView;


}


@Override
public void onStart() {

    super.onStart();

    FirebaseRecyclerAdapter<InterestActivity.Interest,InterestViewHolder > firebaseRecyclerAdapter = new FirebaseRecyclerAdapter<InterestActivity.Interest, InterestViewHolder>(


            InterestActivity.Interest.class,
            R.layout.interest_row,
            InterestViewHolder.class,
            mDatabase



    ) {
        @Override
        protected void populateViewHolder(InterestViewHolder viewHolder, InterestActivity.Interest model, int position) {


            viewHolder.setTitle(model.getTitle());
            viewHolder.setDesc(model.getDescription());
        }

    };


        mInterestList.setAdapter(firebaseRecyclerAdapter);


}


public static class InterestViewHolder extends RecyclerView.ViewHolder {

    View mView;

    public InterestViewHolder(View itemView) {
        super(itemView);
        mView = itemView;
    }

    public void setTitle(String title) {

        TextView interest_title = (TextView) mView.findViewById(R.id.Interest_Title);
        interest_title.setText(title);

    }
    public void setDesc(String desc) {

        TextView interest_Description = (TextView) mView.findViewById(R.id.interest_Description);
        interest_Description.setText(desc);
    }



}

}

这是我的InterestActivity Class

public class InterestActivity {

public class Interest {

    private String title;
    private String description;
    private String image;
    private String uid;

    public Interest(){

    }


    public Interest(String title, String description, String image, String uid) {
        this.title = title;
        this.description = description;
        this.image = image;
        this.uid = uid;
    }

    public String getTitle() {
        return title;
    }

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

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public String getImage() {
        return image;
    }

    public void setImage(String image) {
        this.image = image;
    }

    public String getUid() {
        return uid;
    }

    public void setUid(String uid) {
        this.uid = uid;
    }
}

}

它没有显示错误，但是当我运行应用程序时它崩溃了。我试着评论这一点[mInterestList.setAdapter(firebaseRecyclerAdapter); ]它没有崩溃。当它崩溃时，我收到以下错误信息。

dRuntime: FATAL EXCEPTION: main
                  Process: com.example.amaobimills.interestmee, PID: 4350
                  com.google.firebase.database.DatabaseException: Class com.example.amaobimills.interestmee.InterestActivity$Interest is missing a constructor with no arguments
                      at com.google.android.gms.internal.zzalq$zza.zze(Unknown Source)
                      at com.google.android.gms.internal.zzalq$zza.zzcc(Unknown Source)
                      at com.google.android.gms.internal.zzalq.zzd(Unknown Source)
                      at com.google.android.gms.internal.zzalq.zzb(Unknown Source)
                      at com.google.android.gms.internal.zzalq.zza(Unknown Source)
                      at com.google.firebase.database.DataSnapshot.getValue(Unknown Source)
                      at com.firebase.ui.database.FirebaseRecyclerAdapter.parseSnapshot(FirebaseRecyclerAdapter.java:147)
                      at com.firebase.ui.database.FirebaseRecyclerAdapter.getItem(FirebaseRecyclerAdapter.java:136)
                      at com.firebase.ui.database.FirebaseRecyclerAdapter.onBindViewHolder(FirebaseRecyclerAdapter.java:176)
                      at android.support.v7.widget.RecyclerView$Adapter.onBindViewHolder(RecyclerView.java:6067)
                      at android.support.v7.widget.RecyclerView$Adapter.bindViewHolder(RecyclerView.java:6100)
                      at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5282)
                      at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5158)
                      at android.support.v7.widget.LinearLayoutManager$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:3379)
                      at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:3188)
                      at android.support.v7.widget.RecyclerView.consumePendingUpdateOperations(RecyclerView.java:1595)
                      at android.support.v7.widget.RecyclerView$1.run(RecyclerView.java:323)
                      at android.view.Choreographer$CallbackRecord.run(Choreographer.java:767)
                      at android.view.Choreographer.doCallbacks(Choreographer.java:580)
                      at android.view.Choreographer.doFrame(Choreographer.java:549)
                      at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:753)
                      at android.os.Handler.handleCallback(Handler.java:739)
                      at android.os.Handler.dispatchMessage(Handler.java:95)
                      at android.os.Looper.loop(Looper.java:135)
                      at android.app.ActivityThread.main(ActivityThread.java:5254)
                      at java.lang.reflect.Method.invoke(Native Method)
                      at java.lang.reflect.Method.invoke(Method.java:372)
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)}

Answer 1

阅读错误消息

com.google.firebase.database.DatabaseException：类com.example.amaobimills.interestmee.InterestActivity $兴趣缺少一个没有参数的构造函数 ...

为Interest类提供一个空构造函数

public Interest() {

}

另外，在Interest中声明static为InterestActivity类，如此

public static class Interest {
    ...

Answer 2

经过一些尝试，这就是我想出的：

1-在一个单独的文件中创建兴趣类。 2-使用InterestActivity.Interest

更改TimeLineFragment类中的每个Interest

这应该有效

setAdapter（firebaseRecyclerAdapter）崩溃我的程序

2 个答案: