com.google.firebase.database.DatabaseException: Failed to convert value of type java.lang.Long to String problem

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英文:

com.google.firebase.database.DatabaseException: Failed to convert value of type java.lang.Long to String problem

问题

public class QuestionsActivity extends AppCompatActivity {

    FirebaseDatabase database = FirebaseDatabase.getInstance();
    DatabaseReference myRef = database.getReference();

    private TextView question, noIndicator;
    private FloatingActionButton bookmarkbtn;
    private LinearLayout optioncontainer;
    private Button shareBtn, nextBtn;
    private int count = 0;
    private List<QuestionsModel> list;
    private int position = 0;
    private int score = 0;
    private int setNo;
    private String category;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_questions);
        Toolbar toolbar = findViewById(R.id.toolbar11);
        setSupportActionBar(toolbar);

        question = findViewById(R.id.question);
        noIndicator = findViewById(R.id.no_indicator);
        bookmarkbtn = findViewById(R.id.bookmark_btn);
        optioncontainer = findViewById(R.id.option_container);
        shareBtn = findViewById(R.id.share_btn);
        nextBtn = findViewById(R.id.next_btn);

        category = getIntent().getStringExtra("category");
        setNo = getIntent().getIntExtra("setNo", 1);

        list = new ArrayList<>();

        myRef.child("SETS").child(category).child("Questions").orderByChild("setNo").equalTo(setNo).addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
                    list.add(snapshot.getValue(QuestionsModel.class));
                }
                if (list.size() > 0) {

                    for (int i = 0; i < 4; i++) {
                        optioncontainer.getChildAt(i).setOnClickListener(new View.OnClickListener() {
                            @Override
                            public void onClick(View v) {
                                checkAnswer((Button) v);
                            }
                        });
                    }

                    playAnim(question, 0, list.get(position).getQuestion());
                    nextBtn.setOnClickListener(new View.OnClickListener() {
                        @Override
                        public void onClick(View v) {
                            nextBtn.setEnabled(false);
                            nextBtn.setAlpha(0.7f);
                            enableoption(true);
                            position++;
                            if (position == list.size()) {
                                return;
                            }
                            count = 0;
                            playAnim(question, 0, list.get(position).getQuestion());
                        }
                    });
                } else {
                    finish();
                    Toast.makeText(QuestionsActivity.this, "no questions", Toast.LENGTH_SHORT).show();
                }
            }

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {
                Toast.makeText(QuestionsActivity.this, databaseError.getMessage(), Toast.LENGTH_SHORT).show();
            }
        });
    }

    private void playAnim(final View view, final int value, final String data) {
        view.animate().alpha(value).scaleX(value).scaleY(value).setDuration(500).setStartDelay(100).setInterpolator(new DecelerateInterpolator()).setListener(new Animator.AnimatorListener() {
            @Override
            public void onAnimationStart(Animator animation) {
                if (value == 0 && count < 4) {
                    String option = "";
                    if (count == 0) {
                        option = list.get(position).getOptionA();
                    } else if (count == 1) {
                        option = list.get(position).getOptionB();
                    } else if (count == 2) {
                        option = list.get(position).getOptionC();
                    } else if (count == 3) {
                        option = list.get(position).getOptionD();
                    }
                    playAnim(optioncontainer.getChildAt(count), 0, option);
                    count++;
                }
            }

            @Override
            public void onAnimationEnd(Animator animation) {
                if (value == 0) {
                    try {
                        ((TextView) view).setText(data);
                        noIndicator.setText(position + 1 + "/" + list.size());
                    } catch (ClassCastException ex) {
                        ((Button) view).setText(data);
                    }
                    view.setTag(data);
                    playAnim(view, 1, data);
                }
            }

            @Override
            public void onAnimationCancel(Animator animation) {

            }

            @Override
            public void onAnimationRepeat(Animator animation) {

            }
        });
    }

    private void checkAnswer(Button selectedoption) {
        enableoption(false);
        nextBtn.setEnabled(true);
        nextBtn.setAlpha(1);
        if (selectedoption.getText().toString().equals(list.get(position).getCorrectAns())) {
            score++;
            selectedoption.setBackgroundTintList(ColorStateList.valueOf(Color.parseColor("#4CAF50")));
        } else {
            selectedoption.setBackgroundTintList(ColorStateList.valueOf(Color.parseColor("#ff0000")));
            Button correctoption = optioncontainer.findViewWithTag(list.get(position).getCorrectAns());
            correctoption.setBackgroundTintList(ColorStateList.valueOf(Color.parseColor("#4CAF50")));
        }
    }

    private void enableoption(boolean enable) {
        for (int i = 0; i < 4; i++) {
            optioncontainer.getChildAt(i).setEnabled(enable);
            if (enable) {
                optioncontainer.getChildAt(i).setBackgroundTintList(ColorStateList.valueOf(Color.parseColor("#989898")));
            }
        }
    }
}

public class QuestionsModel {

    private String optionA, optionB, optionC, optionD, correctAns;
    private int setNo;
    private String question;

    public QuestionsModel() {

    }

    public QuestionsModel(String question, String optionA, String optionB, String optionC, String optionD, String correctAns, int setNo) {
        this.setNo = setNo;
        this.question = question;
        this.optionA = optionA;
        this.optionB = optionB;
        this.optionC = optionC;
        this.optionD = optionD;
        this.correctAns = correctAns;
    }

    public String getQuestion() {
        return question;
    }

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

    public String getOptionA() {
        return optionA;
    }

    public void setOptionA(String optionA) {
        this.optionA = optionA;
    }

    public String getOptionB() {
        return optionB;
    }

    public void setOptionB(String optionB) {
        this.optionB = optionB;
    }

    public String getOptionC() {
        return optionC;
    }

    public void setOptionC(String optionC) {
        this.optionC = optionC;
    }

    public String getOptionD() {
        return optionD;
    }

    public void setOptionD(String optionD) {
        this.optionD = optionD;
    }

    public String getCorrectAns() {
        return correctAns;
    }

    public void setCorrectAns(String correctAns) {
        this.correctAns = correctAns;
    }

    public int getSetNo() {
        return setNo;
    }

    public void setSetNo(int setNo) {
        this.setNo = setNo;
    }
}
英文:

I have a quiz app
i add the Question on my firebase Realtie Database
when i want to see it show me this error

> com.google.firebase.database.DatabaseException: Failed to convert value of type java.lang.Long to String"

in this page :

> com.quiz.footwikiquiz.questions.QuestionsActivity$1.onDataChange(QuestionsActivity.java:72)

heres my code for QuestionsActivity :

public class QuestionsActivity extends AppCompatActivity {
FirebaseDatabase database = FirebaseDatabase.getInstance();
DatabaseReference myRef = database.getReference();
private TextView question,noIndicator;
private FloatingActionButton bookmarkbtn;
private LinearLayout optioncontainer;
private Button shareBtn,nextBtn;
private int count=0;
private List&lt;QuestionsModel&gt; list;
private int position =0;
private int score=0;
private int setNo;
private String category;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_questions);
Toolbar toolbar = findViewById(R.id.toolbar11);
setSupportActionBar(toolbar);
question = findViewById(R.id.question);
noIndicator = findViewById(R.id.no_indicator);
bookmarkbtn = findViewById(R.id.bookmark_btn);
optioncontainer = findViewById(R.id.option_container);
shareBtn = findViewById(R.id.share_btn);
nextBtn = findViewById(R.id.next_btn);
category = getIntent().getStringExtra(&quot;category&quot;);
setNo = getIntent().getIntExtra(&quot;setNo&quot;,1);
list = new ArrayList&lt;&gt;();
myRef.child(&quot;SETS&quot;).child(category).child(&quot;Questions&quot;).orderByChild(&quot;setNo&quot;).equalTo(setNo).addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
list.add(snapshot.getValue(QuestionsModel.class));
}
if (list.size() &gt; 0) {
for (int i=0 ; i&lt;4 ;i++) {
optioncontainer.getChildAt(i).setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
checkAnswer((Button)v);
}
});
}
playAnim(question,0,list.get(position).getQuestion());
nextBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
nextBtn.setEnabled(false);
nextBtn.setAlpha(0.7f);
enableoption(true);
position++;
if (position == list.size()) {
return;
}
count= 0;
playAnim(question,0,list.get(position).getQuestion());
}
});
}else {
finish();
Toast.makeText(QuestionsActivity.this, &quot;no questions&quot;, Toast.LENGTH_SHORT).show();
}
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
Toast.makeText(QuestionsActivity.this, databaseError.getMessage(), Toast.LENGTH_SHORT).show();
}
});
}
private void playAnim(final View view , final int value , final String data) {
view.animate().alpha(value).scaleX(value).scaleY(value).setDuration(500).setStartDelay(100).setInterpolator(new DecelerateInterpolator()).setListener(new Animator.AnimatorListener() {
@Override
public void onAnimationStart(Animator animation) {
if (value ==0 &amp;&amp; count&lt;4) {
String option =&quot;&quot;;
if (count == 0) {
option = list.get(position).getOptionA();
} else if (count == 1) {
option = list.get(position).getOptionB();
} else if (count == 2) {
option = list.get(position).getOptionC();
} else if (count == 3) {
option = list.get(position).getOptionD();
}
playAnim(optioncontainer.getChildAt(count),0,option);
count++;
}
}
@Override
public void onAnimationEnd(Animator animation) {
if (value ==0 ) {
try {
((TextView)view).setText(data);
noIndicator.setText(position+1+&quot;/&quot;+list.size());
}catch (ClassCastException ex){
((Button)view).setText(data);
}
view.setTag(data);
playAnim(view,1,data);
}
}
@Override
public void onAnimationCancel(Animator animation) {
}
@Override
public void onAnimationRepeat(Animator animation) {
}
});
}
private void checkAnswer(Button selectedoption) {
enableoption(false);
nextBtn.setEnabled(true);
nextBtn.setAlpha(1);
if (selectedoption.getText().toString().equals(list.get(position).getCorrectAns())) {
score++;
selectedoption.setBackgroundTintList(ColorStateList.valueOf(Color.parseColor(&quot;#4CAF50&quot;)));
} else {
selectedoption.setBackgroundTintList(ColorStateList.valueOf(Color.parseColor(&quot;#ff0000&quot;)));
Button correctoption = optioncontainer.findViewWithTag(list.get(position).getCorrectAns());
correctoption.setBackgroundTintList(ColorStateList.valueOf(Color.parseColor(&quot;#4CAF50&quot;)));
}
}
private void enableoption(boolean enable){
for (int i=0 ; i&lt;4 ;i++) {
optioncontainer.getChildAt(i).setEnabled(enable);
if (enable) {
optioncontainer.getChildAt(i).setBackgroundTintList(ColorStateList.valueOf(Color.parseColor(&quot;#989898&quot;)));
}
}
}
}

and this is the QuestionModel code :

public class QuestionsModel {
private String optionA, optionB, optionC, optionD, correctAns;
private int setNo;
private String question;
public QuestionsModel(){
}
public QuestionsModel(String question, String optionA, String optionB, String optionC, String optionD, String correctAns,int setNo) {
this.setNo = setNo;
this.question = question;
this.optionA = optionA;
this.optionB = optionB;
this.optionC = optionC;
this.optionD = optionD;
this.correctAns = correctAns;
}
public String getQuestion() {
return question;
}
public void setQuestion(String question) {
this.question = question;
}
public String getOptionA() {
return optionA;
}
public void setOptionA(String optionA) {
this.optionA = optionA;
}
public String getOptionB() {
return optionB;
}
public void setOptionB(String optionB) {
this.optionB = optionB;
}
public String getOptionC() {
return optionC;
}
public void setOptionC(String optionC) {
this.optionC = optionC;
}
public String getOptionD() {
return optionD;
}
public void setOptionD(String optionD) {
this.optionD = optionD;
}
public String getCorrectAns() {
return correctAns;
}
public void setCorrectAns(String correctAns) {
this.correctAns = correctAns;
}
public int getSetNo() {
return setNo;
}
public void setSetNo(int setNo) {
this.setNo = setNo;
}
}

this is my firebase

com.google.firebase.database.DatabaseException: Failed to convert value of type java.lang.Long to String problem

答案1

得分: 0

你将答案（optionA、optionB等）存储为 Question1 中的数字，但你尝试将它们转换为字符串。

如果你直接访问 DataSnapshot 值，可以通过以下方式获取对象：

myRef.child("SETS").child(category).child("Questions").orderByChild("setNo").equalTo(setNo).addListenerForSingleValueEvent(new ValueEventListener() {
    @Override
    public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
        for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
            Log.i("Database", snapshot.child("optionA").getValue());
        }
    }
});

如果你想将选项放入你的 Java 类中，唯一能够做到的方式是将所有答案声明为 Object：

public class QuestionsModel {

    private Object optionA, optionB, optionC, optionD, correctAns;
    private int setNo;
    private String question;

    public QuestionsModel(){

    }

    public QuestionsModel(String question, String optionA, String optionB, String optionC, String optionD, String correctAns,int setNo) {
        this.setNo = setNo;
        this.question = question;
        this.optionA = optionA;
        this.optionB = optionB;
        this.optionC = optionC;
        this.optionD = optionD;
        this.correctAns = correctAns;
    }

    public String getQuestion() {
        return question;
    }

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

    public Object getOptionA() {
        return optionA;
    }

    public void setOptionA(Object optionA) {
        this.optionA = optionA;
    }

    public Object getOptionB() {
        return optionB;
    }

    public void setOptionB(Object optionB) {
        this.optionB = optionB;
    }

    public Object getOptionC() {
        return optionC;
    }

    public void setOptionC(Object optionC) {
        this.optionC = optionC;
    }

    public Object getOptionD() {
        return optionD;
    }

    public void setOptionD(Object optionD) {
        this.optionD = optionD;
    }

    public Object getCorrectAns() {
        return correctAns;
    }

    public void setCorrectAns(Object correctAns) {
        this.correctAns = correctAns;
    }

    public int getSetNo() {
        return setNo;
    }

    public void setSetNo(int setNo) {
        this.setNo = setNo;
    }
}

但总的来说，我建议修复数据库中 Question1 的答案类型，将它们存储为字符串值。

英文:

You're storing the answers (optionA, optionB, etc) as numbers in Question1, but you are trying to cast them to a string.

If you're directly accessing the DataSnapshot value you can get the object with:

myRef.child(&quot;SETS&quot;).child(category).child(&quot;Questions&quot;).orderByChild(&quot;setNo&quot;).equalTo(setNo).addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
Log.i(&quot;Database&quot;, snapshot.child(&quot;optionA&quot;).getValue();
}

If you want to put the options into your Java class, the only way you can do that is by declaring all answers as Object:

public class QuestionsModel {
private Object optionA, optionB, optionC, optionD, correctAns;
private int setNo;
private String question;
public QuestionsModel(){
}
public QuestionsModel(String question, String optionA, String optionB, String optionC, String optionD, String correctAns,int setNo) {
this.setNo = setNo;
this.question = question;
this.optionA = optionA;
this.optionB = optionB;
this.optionC = optionC;
this.optionD = optionD;
this.correctAns = correctAns;
}
public String getQuestion() {
return question;
}
public void setQuestion(String question) {
this.question = question;
}
public Object getOptionA() {
return optionA;
}
public void setOptionA(Object optionA) {
this.optionA = optionA;
}
public Object getOptionB() {
return optionB;
}
public void setOptionB(Object optionB) {
this.optionB = optionB;
}
public Object getOptionC() {
return optionC;
}
public void setOptionC(Object optionC) {
this.optionC = optionC;
}
public Object getOptionD() {
return optionD;
}
public void setOptionD(Object optionD) {
this.optionD = optionD;
}
public Object getCorrectAns() {
return correctAns;
}
public void setCorrectAns(Object correctAns) {
this.correctAns = correctAns;
}
public int getSetNo() {
return setNo;
}
public void setSetNo(int setNo) {
this.setNo = setNo;
}
}

But in general I'd recommend fixing the type of the answers to Question1 in the database, and storing them as string values.

huangapple
  • 本文由 发表于 2020年9月16日 06:43:13
  • 转载请务必保留本文链接：https://go.coder-hub.com/63910777.html
  • android
  • firebase
  • firebase-realtime-database
  • java
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