java - 为什么 Firebase 中的数据没有显示在我的 TextView 中？

Question

我已将问题作为 json 问题数组发布在 Firebase 实时数据库上，并尝试将其从 Firebase 检索到我的应用程序，但我在 TextView 中看到与我在 xml 文件中设置为默认值相同的文本所以请帮忙我的数据库是一个包含问题类的json数组，其中有五个类别，每个类别有9个问题字段，其中有六个部分；问题、四个选项和正确答案(所有字符串)

public class Questions extends AppCompatActivity {
DatabaseReference dref;
DatabaseReference ref,ques;
TextView question,option1,option2,option3,option4;
ImageButton imageButton;

int val,correct,wrong,score;

public Questions() {
    this.val = 0;
    this.correct=0;
    this.wrong=0;
    this.score=0;
}

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_questions);
    question=findViewById(R.id.question);
    imageButton=findViewById(R.id.next);
    option1=findViewById(R.id.opt1);
    option2=findViewById(R.id.opt2);
    option3=findViewById(R.id.opt3);
    option4=findViewById(R.id.opt4);
    dref= FirebaseDatabase.getInstance().getReference();
    Intent intent=getIntent();
    Integer value=intent.getIntExtra("type",0);
   switch (value)
   {
       case 1:
           ref=dref.child("Questions").child("Bollywood");

            break;
       case 2:
           ref=dref.child("Questions").child("Sports");
           break;
       case 3:
           ref=dref.child("Questions").child("Technology");
           break;
       case 4:
           ref=dref.child("Questions").child("Entertainment");
           break;
       case 5:
           ref=dref.child("Questions").child("Miscellaneous");
           break;
           default:
               break;
   }
    ques = ref.child(String.valueOf(val));
    ques.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
            QAnswer qAnswer=dataSnapshot.getValue(QAnswer.class);
            question.setText(qAnswer.getQuestion());
            option1.setText(qAnswer.getOption1());
            option2.setText(qAnswer.getOption2());
            option3.setText(qAnswer.getOption3());
            option4.setText(qAnswer.getOption4());
        }

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

        }
    });
   imageButton.setOnClickListener(new View.OnClickListener() {
       @Override
       public void onClick(View v) {
           if(val>15)
           {

           }
           else {
               ques = ref.child(String.valueOf(++val));
               ques.addValueEventListener(new ValueEventListener() {
                   @Override
                   public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                       final QAnswer qAnswer=dataSnapshot.getValue(QAnswer.class);
                       Log.d("value",qAnswer.getQuestion()+qAnswer.getAnswer());
                       question.setText(qAnswer.getQuestion());
                       option1.setText(qAnswer.getOption1());
                       option2.setText(qAnswer.getOption2());
                       option3.setText(qAnswer.getOption3());
                       option4.setText(qAnswer.getOption4());
                       option1.setOnClickListener(new View.OnClickListener() {
                           @Override
                           public void onClick(View v) {
                               if(qAnswer.getOption1()==qAnswer.getAnswer())
                               {
                                   option1.setBackgroundColor(getResources().getColor(R.color.colorPrimary));
                                   correct++;
                               }
                               else {
                                   option1.setBackgroundColor(getResources().getColor(R.color.colorAccent));
                                   wrong++;

                               }
                           }
                       });
                       option2.setOnClickListener(new View.OnClickListener() {
                           @Override
                           public void onClick(View v) {

                           }
                       });
                       option3.setOnClickListener(new View.OnClickListener() {
                           @Override
                           public void onClick(View v) {

                           }
                       });
                       option4.setOnClickListener(new View.OnClickListener() {
                           @Override
                           public void onClick(View v) {

                           }
                       });
                   }

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

                   }
               });

           }
       }
   });


}
}

这是我的问题模型类:

public class QAnswer {
String question;
String option1;
String option2;
String option3;
String option4;
String answer;

public QAnswer(String question, String option1, String option2, String option3, String option4, String answer) {
    this.question = question;
    this.option1 = option1;
    this.option2 = option2;
    this.option3 = option3;
    this.option4 = option4;
    this.answer = answer;
}

public String getQuestion() {
    return question;
}

public void setQuestion(String question) {
    this.question = question;
}

public String getOption1() {
    return option1;
}

public void setOption1(String option1) {
    this.option1 = option1;
}

public String getOption2() {
    return option2;
}

public void setOption2(String option2) {
    this.option2 = option2;
}

public String getOption3() {
    return option3;
}

public void setOption3(String option3) {
    this.option3 = option3;
}

public String getOption4() {
    return option4;
}

public void setOption4(String option4) {
    this.option4 = option4;
}

public String getAnswer() {
    return answer;
}

public void setAnswer(String answer) {
    this.answer = answer;
}
 }

Answer 1

将其添加到您的问题模型类中

public QAnswer(){
}

在此之前

public QAnswer(String question, String option1, String option2, String option3, String option4, String answer) {
    this.question = question;
    this.option1 = option1;
    this.option2 = option2;
    this.option3 = option3;
    this.option4 = option4;
    this.answer = answer;
}