单击单选按钮后，如何更新 Firebase 中的数据？

Question

我正在设计一个票应用程序来获取票。每个餐厅都包含三个派对大小的票号。单选按钮是选项。

我尝试更新 Firebase。

如果用户点击了btnPartSize1_2，希望将QueueA“0”改为1

然而，它不能。我想知道代码中存在一些问题，我正在尝试修改 btnPartySize 按钮部分，以便我不需要重复三次相同的代码。

请帮忙。

The image show the data structure in Firebase

public class Queue extends AppCompatActivity {

    RadioGroup radioGroup;
    RadioButton btnPartySize1_2, btnPartySize3_4, btnPartySize5_6;
    Button buttonQueue;

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

        buttonQueue = (Button) findViewById(R.id.btnQueue);
        btnPartySize1_2 = (RadioButton) findViewById(R.id.btnPartySize1_2);
        btnPartySize3_4 = (RadioButton) findViewById(R.id.btnPartySize3_4);
        btnPartySize5_6 = (RadioButton) findViewById(R.id.btnPartySize5_6);
        final RadioGroup radioGroup = (RadioGroup) findViewById(R.id.radioGroup);

        FirebaseDatabase database = FirebaseDatabase.getInstance();
        final DatabaseReference table_user = database.getReference("Restaurant");
        final DatabaseReference QueueA = FirebaseDatabase.getInstance().getReference("QueueA");
        final DatabaseReference QueueB = FirebaseDatabase.getInstance().getReference("QueueB");
        final DatabaseReference QueueC = FirebaseDatabase.getInstance().getReference("QueueC");

        buttonQueue.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
              if(btnPartySize1_2.isChecked()) {

                            ValueEventListener eventListener = new ValueEventListener() {
                                @Override
                                public void onDataChange(DataSnapshot dataSnapshot) {
                                    int QueueA = dataSnapshot.child("QueueA").getValue(Integer.class);
                                    QueueA++;
                                    this.child("QueueA").setValue(QueueA);
                                    Toast.makeText(Queue.this, "You have collected", Toast.LENGTH_SHORT).show();
                                }

                                @Override
                                public void onCancelled(DatabaseError databaseError) {

                                }
                            };
                            QueueA.addListenerForSingleValueEvent(eventListener);
                        } else if (btnPartySize3_4.isChecked()) {


                            ValueEventListener eventListener = new ValueEventListener() {
                                @Override
                                public void onDataChange(DataSnapshot dataSnapshot) {
                                    int counter = dataSnapshot.child("counter").getValue(Integer.class);
                                    counter++;
                                    QueueB.child("counter").setValue(counter);
                                    Toast.makeText(Queue.this, "You have collected", Toast.LENGTH_SHORT).show();
                                }

                                @Override
                                public void onCancelled(DatabaseError databaseError) {

                                }
                            };
                            QueueB.addListenerForSingleValueEvent(eventListener);

                        } else if (btnPartySize5_6.isChecked()) {


                            ValueEventListener eventListener = new ValueEventListener() {
                                @Override
                                public void onDataChange(DataSnapshot dataSnapshot) {
                                    int counter = dataSnapshot.child("counter").getValue(Integer.class);
                                    counter++;
                                    QueueC.child("counter").setValue(counter);
                                    Toast.makeText(Queue.this, "You have collected", Toast.LENGTH_SHORT).show();
                                }

                                @Override
                                public void onCancelled(DatabaseError databaseError) {

                                }
                            };
                            QueueC.addListenerForSingleValueEvent(eventListener);

                        } else {

                            Toast.makeText(Queue.this, "Please choose party size", Toast.LENGTH_SHORT).show();
                        }


            }
        });

}

有人可以帮忙吗？ 真诚希望您的帮助！！

Answer 1

为使其更简单，请更改代码的逻辑。创建一个 ValueEventListener 对象并在 onDataChange() 方法中添加有关单选按钮的逻辑。

if(btnPartySize1_2.isChecked()) {
    int QueueA = dataSnapshot.child("QueueA").getValue(Integer.class);
    QueueA++;
    this.child("QueueA").setValue(QueueA);
} else if () {
    int counter = dataSnapshot.child("counter").getValue(Integer.class);
    counter++;
    QueueB.child("counter").setValue(counter);
}
// and so on.

Answer 2

引用有误，需要修改：

目前这是您的参考：

 FirebaseDatabase database = FirebaseDatabase.getInstance();
    final DatabaseReference table_user = database.getReference("Restaurant");
    final DatabaseReference QueueA = FirebaseDatabase.getInstance().getReference("QueueA");
    final DatabaseReference QueueB = FirebaseDatabase.getInstance().getReference("QueueB");
    final DatabaseReference QueueC = FirebaseDatabase.getInstance().getReference("QueueC");

现在你有：

 rootnode
     Category
     Restaurant
         01
           Key:value
           key:value //one of those is QueueA

所以试试这个：

       FirebaseDatabase database = FirebaseDatabase.getInstance();
       final DatabaseReference ref=database.getReference().child("Restaurant").child("01").child("QueueA");

你必须按顺序从上到下，否则参考将是错误的。