我想从 firebase 数据库的单个 Textview 中获取完整的数据

Question

我创建了一个条形码扫描仪应用程序，它读取条形码 ID 并需要将输出作为语音输出。为了阅读所有内容，我需要在一个 TextView 中一起获取所有数据。我尽我所能从数据库中添加查询。但它只在TextView 中显示为com.google.firebase.database.Query@9fc9e4d，而我的应用程序TTS 引擎清楚地读取了它。但我需要将其设置为数据库中单个TextView 下的所有数据才能说出。请帮我？？？？这里只附上结果处理方法。

@Override 
public void handleResult(Result result) { final String scanResult = result.getText();

    databasefetch = FirebaseDatabase.getInstance().getReference("save");
    databasefetch.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(@NonNull DataSnapshot dataSnapshot) {



            setContentView(R.layout.activity_second);
            TextView text = (TextView) findViewById(R.id.textView3);
            String tst = databasefetch.child("save").orderByChild("id").equalTo(scanResult).toString();
            text.setText(tst);



            //text to speech
            String  toSpeak=text.getText().toString();
            //Toast.makeText(getApplicationContext(),toSpeak,Toast.LENGTH_SHORT).show();
            txt.speak(toSpeak,TextToSpeech.QUEUE_FLUSH,null);


        }

        @Override
        public void onCancelled(@NonNull DatabaseError databaseError) {

        }
    });
}

Answer 1

试试这样的

@Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        for (DataSnapshot postSnapshot: dataSnapshot.getChildren()) {
            // TODO: handle the post
            YourModelClass object = postSnapshot.getValue(YourModelClass.class);
            text.setText(object.getId().equalsIgnoreCase(scanResult) ? object.getDescription() : "");
        }
    }

Answer 2

无需运行多个查询来过滤基于id 的数据。检查以下：

databasefetch = FirebaseDatabase.getInstance().getReference("save");
databasefetch.orderByChild("id").equalTo(scanResult).addValueEventListener(new ValueEventListener() {
    @Override
    public void onDataChange(@NonNull DataSnapshot dataSnapshot) {

        String  toSpeak = "";

        for (DataSnapshot childSnapshot: dataSnapshot.getChildren()) {

            String name = childSnapshot.child("name").getValue(String.class);
            String price = childSnapshot.child("price").getValue(String.class);
            String details = childSnapshot.child("details").getValue(String.class);

            toSpeak = name + ", " + price + ", " + details;
        }

        text.setText(toSpeak);

        txt.speak(toSpeak, TextToSpeech.QUEUE_FLUSH,null);
    }

    @Override
    public void onCancelled(@NonNull DatabaseError databaseError) {

    }
});