java - 我需要将所有工作概述保存在一个数组列表中，抱歉，如果有一个明显的答案，我对 java 和 android 很陌生

Question

数据库

我尝试过使用 orderByChild 和嵌套 for 循环，但我不确定如何使用哪种方法或如何使用它。目的是在JOBOVERVIEW中显示各种字符串的卡片。各位 stackoverflowrians 有答案吗？我已经被困了一段时间，不知道从哪里开始。

干杯，请不要讨厌。

package com.example.sherwin.todo;

import java.util.ArrayList;

public class JobList extends Fragment {

    public JobList() {
    }
    public static JobList newInstance() {
        JobList fragment = new JobList();

        return fragment;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View rootView =  inflater.inflate(R.layout.fragment_job_list, container, false);
        final RecyclerView recyclerView = (RecyclerView)rootView.findViewById(R.id.job_list_recycler_view);

        LinearLayoutManager llm = new LinearLayoutManager(getContext());
        recyclerView.setLayoutManager(llm);
        final ArrayList<JobClass> joblistclass  = new ArrayList<>();

        final DatabaseReference myRef = FirebaseDatabase.getInstance().getReference("USERS/04950F4AE53F80/JOBS");



        myRef.addValueEventListener(new ValueEventListener() {

            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                    for (DataSnapshot data:dataSnapshot.getChildren()
                            ) {
                        if (data.getChildren().equals("JOBOVERVIEW")){
                            JobClass jblst = data.getValue(JobClass.class);
                            joblistclass.add(jblst);
                        }
                    }

                final JobListRecyclerAdapter adapterb = new JobListRecyclerAdapter(joblistclass);
                recyclerView.setAdapter(adapterb);

            }



            @Override
            public void onCancelled(DatabaseError error) {
                // Failed to read value
                Log.w("TAG:", "Failed to read value.", error.toException());
            }
        });


        return rootView;
    }

}

Answer 1

要实现此目的，请使用以下代码:

DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference jobsRef = rootRef
        .child("USERS")
        .child("04950F4AE53F80")
        .child("JOBS");
ValueEventListener eventListener = new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        for(DataSnapshot ds : dataSnapshot.getChildren()) {
            String jobDate = ds.child("JOBOVERVIEW").child("jobDate").getValue(String.class);
            Log.d("TAG", jobDate);
        }
    }

    @Override
    public void onCancelled(DatabaseError databaseError) {}
};
jobsRef.addListenerForSingleValueEvent(eventListener);

输出将是:

29/09
2/2
//and so on