Android Studio中Firebase的onDataChange无限加载问题排查

架构老林

2026-7-28

Firebase Realtime Database onDataChange无限加载问题解决

问题背景

调用addListenerForSingleValueEvent()后，onDataChange()持续无限加载，无法从Firebase Realtime Database获取数据。该功能此前正常运行6个月，无征兆突然失效。已尝试重新安装google-services.json文件、检查数据库访问权限，均无效果。启用Firebase调试日志后，发现报错为com.google.firebase.database.tubesock.WebSocketException: unknown host: #####.firebaseio.com，问题与WiFi网络环境相关。

解决方法

在获取FirebaseDatabase实例后，添加goOffline()和goOnline()调用，重置数据库连接状态：

FirebaseDatabase database = FirebaseDatabase.getInstance();
// 重置数据库连接，解决WebSocket未知主机问题
database.goOffline();
database.goOnline();

DatabaseReference usersRef = database.getReference().child("users");

usersRef.addListenerForSingleValueEvent(new ValueEventListener() {
    @Override
    public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
        if (!dataSnapshot.child(userName).exists()) {
            Toast.makeText(LogInActivity.this,"Incorrect credentials were entered!", Toast.LENGTH_SHORT).show();
            return;
        }
        else if (!dataSnapshot.child(userName).child("password").getValue().toString().equals(et_enterPassword.getText().toString())) {
            Toast.makeText(LogInActivity.this,"Incorrect credentials were entered!", Toast.LENGTH_SHORT).show();
            return;
        }

        Intent homePageIntent = new Intent(LogInActivity.this, HomePageActivity.class);
        startActivity(homePageIntent);
    }
    @Override
    public void onCancelled(DatabaseError databaseError) {
       Toast.makeText(LogInActivity.this,"An error occurred!", Toast.LENGTH_SHORT).show();
    }
});