从Firebase数据库接收数字数据

问题描述

我想在TextView中显示分数的数值，但是应用程序始终关闭。

这是我的代码

FirebaseDatabase database = FirebaseDatabase.getInstance();
        FirebaseUser currentFirebaseUser = FirebaseAuth.getInstance().getCurrentUser();
        DatabaseReference myRef = database.getReference("users").child(currentFirebaseUser.getUid());

        // Read from the database
        myRef.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                String valuePoints = dataSnapshot.child("current_points").getValue(String.class);
                mTextViewPoints = findViewById(R.id.current_points);
                mTextViewPoints.setText(valuePoints);
            }

            @Override
            public void onCancelled(DatabaseError error) {
                // Failed to read value
                // Log.w(TAG,"Failed to read value.",error.toException());
            }
        });
    }```

Other values that contain letters are numbers he displays,but when it comes only to numbers he closes.
Where am I going wrong?

解决方法

Vanderclin Rocha亲爱的

最初，无法在回调ValueEventListener中定义TextView，应在启动视图时定义您。

代码textView中的问题返回null，您可以进行调试并查看它。 这是获取数据并将其设置为TextView的当前方法。

FirebaseDatabase database = FirebaseDatabase.getInstance();
    FirebaseUser currentFirebaseUser = FirebaseAuth.getInstance().getCurrentUser();
    DatabaseReference myRef = database.getReference("users").child(currentFirebaseUser.getUid());

TextView mTextViewPoints = findViewById（R.id.current_points）;

    // Read from the database
    myRef.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            String valuePoints = dataSnapshot.child("current_points").getValue(String.class);
            mTextViewPoints.setText(valuePoints);
        }

        @Override
        public void onCancelled(DatabaseError error) {
            // Failed to read value
            // Log.w(TAG,"Failed to read value.",error.toException());
        }
    });
}

我希望这对您有帮助