如何将单个firebase节点添加到listview中？

Question

我想在列表视图中添加名称节点，如何在listview中添加单个壁炉节点？我尝试了几件事，但无法做到，请有人告诉我该怎么做，这是我的代码，我收到错误 txt_one。的setText（tecnames）;它说它应该是char

这是我的火力库数据库：

代码

public class Technician extends Activity {
    private DatabaseReference mDatabase;
    ListView listView;
    ArrayList<String> tecnames = new ArrayList<>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_technician);
        ImageButton Back_Btn = (ImageButton) findViewById(R.id.back);
        Back_Btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent i = new Intent(Technician.this, Skills.class);
                startActivity(i);
                finish();
            }
        });
        FirebaseDatabase database = FirebaseDatabase.getInstance();
        DatabaseReference myRef = database.getReference("user").child("name");
        myRef.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                // This method is called once with the initial value and again
                // whenever data at this location is updated.
                String value = dataSnapshot.getValue(String.class);
                Pojo pojo=new Pojo();
                tecnames.add(pojo.getName(value));
            }

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


        listView = (ListView) findViewById(R.id.list_item);
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {


                Intent intent = new Intent(Technician.this, Book_Now.class);
                startActivity(intent);
                finish();
            }
        });

        Technician.CostumAdapter costumAdapter = new Technician.CostumAdapter();
        listView.setAdapter(costumAdapter);

    }
}

这是我的BaseAdapter

private class CostumAdapter extends BaseAdapter {


    @Override
    public int getCount() {
        return tecnames.size();
    }

    @Override
    public Object getItem(int i) {
        return null;
    }

    @Override
    public long getItemId(int i) {
        return 0;
    }

    @Override
    public View getView(int i, View view, ViewGroup viewGroup) {

        view = getLayoutInflater().inflate(R.layout.cuctom_listview, null);
        TextView txt_one = (TextView) view.findViewById(R.id.skill_txt);
        txt_one.setText(tecnames);
        return view;
    }

}

Answer 1

当您使用database.getReference("user").child("name")附加监听器时，它会将监听器附加到/user/name。从您分享的屏幕截图中，该位置不存在。

如果您知道要收听的用户的UID，则可以附加一个监听器：

DatabaseReference myRef = database.getReference("user").child(uid).child("name");
myRef.addValueEventListener(new ValueEventListener() {

或更短：

DatabaseReference myRef = database.getReference("user/"+uid+"/name");
myRef.addValueEventListener(new ValueEventListener() {

另一方面，如果您不知道UID，则必须侦听整个/user节点，然后导航到{{{}中的正确用户及其name属性。 1}}回调：

onDataChange

需要DatabaseReference myRef = database.getReference("user"); myRef.addValueEventListener(new ValueEventListener() { @Override public void onDataChange(DataSnapshot dataSnapshot) { for (DataSnapshot childSnapshot: dataSnapshot.getChildren()) { String value = childSnapshot.getValue(String.class); Pojo pojo=new Pojo(); tecnames.add(pojo.getName(value)); } } @Override public void onCancelled(DatabaseError error) { // Failed to read value Log.w(TAG, "Failed to read value.", error.toException()); } }); 以上的循环，因为dataSnapshot.getChildren()下可能有多个用户。在这种情况下，快照包含这些用户节点的列表。