Android 为什么我无法从Firebase检索该值

我能够构建apk，我有LoginActivity.java、SignupActivity.java、StoreNameAndType.java和User.java、RetrieveDataActivity.java

我还能够将apk部署到我的android手机中，应用程序与layout loginactivity、signupactivity、StoreName和TypeActivity完美配合

retrieveDataActivity的布局是在我在登录布局中完成登录之后。但是，当它移动到layout retrievedataactivity时，它将在10秒内显示布局UI，并崩溃

为什么我不能从firebase的用户那里检索到一堆数据？我在YouTube上看了教程，但是布局崩溃了。我的密码有问题吗

我以用户身份登录（3wgmOhWlUUcyoBQXKZWnhw3K7Ik2）

这是我的数据库树。我想从用户id（yKlWu19vhqQXfL2tDlBNfMSduMe2）检索所有信息

这是我的规则

{
  "rules": {
      ".read": "auth != null",
      ".write": "auth != null"
  }
}

这里是我的RetrieveDataActivity.java

public class RetrieveDataActivity extends AppCompatActivity implements 
  ValueEventListener {

    private DatabaseReference databaseReference, mNameReference, 
      mTypeReference, mLocationReference, mLatReference, mLongReference;
    private TextView mNameView, mTypeView, mLatView, mLongView;

    @Override
    public void onCreate( Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_retrievedata);

    databaseReference = FirebaseDatabase.getInstance().getReference().child("yKlWu19vhqQXfL2tDlBNfMSduMe2");
    mNameReference = databaseReference.child("name");
    mTypeReference = databaseReference.child("type");
    mLocationReference = databaseReference.child("location");
    mLatReference = mLocationReference.child("latitude");
    mLongReference = mLocationReference.child("longitude");
    mNameView = (TextView) findViewById(R.id.textViewName);
    mTypeView = (TextView) findViewById(R.id.textViewType);
    mLatView = (TextView) findViewById(R.id.textViewLat);
    mLongView = (TextView) findViewById(R.id.textViewLong);

}

    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
    if(dataSnapshot.getValue(String.class)!=null)
    {
        String key = dataSnapshot.getKey();

        if(key.equals("name"))
        {
            String name = dataSnapshot.getValue(String.class);
            mNameView.setText(name);

        }else if(key.equals("type"))
        {
            String type = dataSnapshot.getValue(String.class);
            mTypeView.setText(type);

        }else if(key.equals("latitude"))
        {

            String lat = dataSnapshot.getValue(String.class);
            mLatView.setText(lat);

        }else if(key.equals("longitude"))
        {

            String log = dataSnapshot.getValue(String.class);
            mLongView.setText(log);

        }


    }

}

@Override
public void onCancelled(DatabaseError databaseError) {

}

@Override
protected void onStart() {
    super.onStart();
    mNameReference.addValueEventListener(this);
    mTypeReference.addValueEventListener(this);
    mLatReference.addValueEventListener(this);
    mLongReference.addValueEventListener(this);

}
}

---

你的应用程序崩溃了吗？如果是这样，请编辑您的问题，以包括logcat中显示的完整堆栈跟踪。u表示所有代码？您没有描述您遇到的问题。如果您收到崩溃或错误消息，请在问题中包含该错误的堆栈跟踪。它将在Android Studio的logcat窗口中打印。如果某件事情没有如预期的那样起作用，请解释你所看到的情况。了解数据库的安全规则也会很有帮助。好的，我将详细介绍。可以吗，先生？这个链接显示了在Android Studio中找到堆栈跟踪的位置。错误消息应该帮助您理解问题，并且您应该在问题中包含错误消息，以便其他人帮助您。

public class RetrieveDataActivity extends AppCompatActivity implements 
  ValueEventListener {

    private DatabaseReference databaseReference, mNameReference, 
      mTypeReference, mLocationReference, mLatReference, mLongReference;
    private TextView mNameView, mTypeView, mLatView, mLongView;

    @Override
    public void onCreate( Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_retrievedata);

    databaseReference = FirebaseDatabase.getInstance().getReference().child("yKlWu19vhqQXfL2tDlBNfMSduMe2");
    mNameReference = databaseReference.child("name");
    mTypeReference = databaseReference.child("type");
    mLocationReference = databaseReference.child("location");
    mLatReference = mLocationReference.child("latitude");
    mLongReference = mLocationReference.child("longitude");
    mNameView = (TextView) findViewById(R.id.textViewName);
    mTypeView = (TextView) findViewById(R.id.textViewType);
    mLatView = (TextView) findViewById(R.id.textViewLat);
    mLongView = (TextView) findViewById(R.id.textViewLong);

}

    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
    if(dataSnapshot.getValue(String.class)!=null)
    {
        String key = dataSnapshot.getKey();

        if(key.equals("name"))
        {
            String name = dataSnapshot.getValue(String.class);
            mNameView.setText(name);

        }else if(key.equals("type"))
        {
            String type = dataSnapshot.getValue(String.class);
            mTypeView.setText(type);

        }else if(key.equals("latitude"))
        {

            String lat = dataSnapshot.getValue(String.class);
            mLatView.setText(lat);

        }else if(key.equals("longitude"))
        {

            String log = dataSnapshot.getValue(String.class);
            mLongView.setText(log);

        }


    }

}

@Override
public void onCancelled(DatabaseError databaseError) {

}

@Override
protected void onStart() {
    super.onStart();
    mNameReference.addValueEventListener(this);
    mTypeReference.addValueEventListener(this);
    mLatReference.addValueEventListener(this);
    mLongReference.addValueEventListener(this);

}
}