将 firebase 值与整数进行比较

Question

我正在尝试将 firebase 数据与整数进行比较，但应用程序崩溃了。 这是代码：

 Firebase myfirebase; int result = 500;

 @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    final TextView mytextview = (TextView) findViewById(R.id.textView);
    Firebase.setAndroidContext(getApplicationContext());
    myfirebase = new Firebase("https://analog-85958.firebaseio.com/number");
    myfirebase.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {

            String mychildtext = dataSnapshot.getValue(String.class);
            mytextview.setText(mychildtext);

            int num = Integer.parseInt(mychildtext);
            if (num == result)
            {
                Toast.makeText(getApplicationContext(),"success",Toast.LENGTH_SHORT).show();
            }
            else
            {
                Toast.makeText(getApplicationContext(),"fail",Toast.LENGTH_SHORT).show();
            }

        }

        @Override
        public void onCancelled(FirebaseError firebaseError) {

数据库结构：

Answer 1

您正在尝试获取一个 String 并且您的数据库中有一个 int：

  @Override
        public void onDataChange(DataSnapshot dataSnapshot) {

            String mychildtext = dataSnapshot.getValue(String.class); //here
            mytextview.setText(mychildtext);

            int num = Integer.parseInt(mychildtext); 

首先得到这样的值：

int mychildtext = Integer.valueOf(dataSnapShot.getValue().toString());

你也可以试试这个来获取值：

int mychildtext = dataSnapshot.getValue(Integer.class);

然后：

mytextview.setText(mychildtext);

最后一部分在这里使用你的值：

int num = mychildtext;

     if (num == result)
                {
                    Toast.makeText(getApplicationContext(),"success",Toast.LENGTH_SHORT).show();
                }
                else
                {
                    Toast.makeText(getApplicationContext(),"fail",Toast.LENGTH_SHORT).show();
                }

编辑：我认为你的参考是错误的，这样改变它：

String url = "https://analog-85958.firebaseio.com/number";
DatabaseReference ref = FirebaseDatabase.getInstance().getReferenceFromUrl(url);
              

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    final TextView mytextview = (TextView) findViewById(R.id.textView);
    Firebase.setAndroidContext(getApplicationContext());
    ref.addValueEventListener(new ValueEventListener() { ....