获取"java.lang.NullPointerException:无法为child()中的参数'pathString'传递null".在Firebase中 [英] Getting "java.lang.NullPointerException: Can't pass null for argument 'pathString' in child()" in Firebase
本文介绍了获取"java.lang.NullPointerException:无法为child()中的参数'pathString'传递null".在Firebase中的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我真的不知道这是怎么回事，我能够添加其他活动的数据.我收到错误消息"java.lang.NullPointerException:无法为child()中的参数'pathString'传递null"，并且不知道如何解决.还有3个其他类，只有另一个类正在将数据添加到Firebase实时数据库存储中.
I don't really know what's wrong here, I am able to add data on the other activity. I am getting error "java.lang.NullPointerException: Can't pass null for argument 'pathString' in child()" and don't know how to fix. There are 3 other classes created only one other is adding data to firebase realtime database storage.
package com.example.akshay.katiroll.FirstScreen;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import com.example.akshay.katiroll.R;
import com.example.akshay.katiroll.SecondScreen.welcome;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
public class Profile extends AppCompatActivity {
EditText fName, lName, PhNo, BDay, Zip;
Button svBtn;
DatabaseReference mDataReference;
String keyUser;
String fNameStr, lNameStr, PhNoStr, BDayStr, ZipStr;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_profile);
keyUser = getIntent().getStringExtra("USER_KEY");
mDataReference = FirebaseDatabase.getInstance().getReference().child("Users").child(keyUser);//error in this line
fName = (EditText) findViewById(R.id.fName);
lName = (EditText) findViewById(R.id.lName);
PhNo = (EditText) findViewById(R.id.phno);
BDay = (EditText) findViewById(R.id.bday);
Zip = (EditText) findViewById(R.id.zip);
svBtn = (Button) findViewById(R.id.svBtn);
svBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
fNameStr = fName.getText().toString();
lNameStr = lName.getText().toString();
PhNoStr = PhNo.getText().toString();
BDayStr = BDay.getText().toString();
ZipStr = Zip.getText().toString();
if(!TextUtils.isEmpty(fNameStr) && !TextUtils.isEmpty(lNameStr) && !TextUtils.isEmpty(PhNoStr)) {
DatabaseReference mDataRef = mDataReference.child("Users").push();
mDataRef.child("firstName").setValue(""+fNameStr);
mDataRef.child("lastName").setValue(""+lNameStr);
mDataRef.child("phoneNumber").setValue(""+PhNoStr);
mDataRef.child("isVerified").setValue("verified");
if(!TextUtils.isEmpty(BDayStr)){
mDataRef.child("birthday").setValue(""+BDayStr);
}else{
mDataRef.child("birthday").setValue("null");
}
if(!TextUtils.isEmpty(ZipStr)){
mDataRef.child("zipcode").setValue("ZipStr");
}else{
mDataRef.child("zipcode").setValue("null");
}
Toast.makeText(Profile.this, "User profile added", Toast.LENGTH_LONG).show();
startActivity(new Intent(Profile.this, welcome.class));
}else{
Toast.makeText(Profile.this, "Failed to create User Account", Toast.LENGTH_LONG).show();
}
}
});
}
}
package com.example.akshay.katiroll.FirstScreen;
import android.content.Intent;
import android.graphics.Color;
import android.support.annotation.NonNull;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.TextUtils;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import com.example.akshay.katiroll.R;
import com.example.akshay.katiroll.SecondScreen.welcome;
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.Task;
import com.google.firebase.auth.AuthResult;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;
import java.util.Iterator;
public class katiRoll extends AppCompatActivity {
EditText userEdit;
EditText passEdit;
String sUser, sPass;
Button sign;
Button reg;
Boolean signInVLogIn;
FirebaseAuth mAuth;
FirebaseAuth.AuthStateListener mAuthListener;
DatabaseReference mDatabaseRef;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_kati_roll);
float Re = 255;
float Gr = 148;
float Bl = 0;
userEdit = (EditText)findViewById(R.id.user);
passEdit = (EditText)findViewById(R.id.pass);
sign = (Button) findViewById(R.id.sign);
reg = (Button) findViewById(R.id.reg);
userEdit.setTextColor(Color.rgb(Re,Gr,Bl));
passEdit.setTextColor(Color.rgb(Re,Gr,Bl));
sign.setTextColor(Color.rgb(Re,Gr,Bl));
reg.setTextColor(Color.rgb(Re,Gr,Bl));
mAuth = FirebaseAuth.getInstance();
mDatabaseRef = FirebaseDatabase.getInstance().getReference().child("Users");
mAuthListener = new FirebaseAuth.AuthStateListener() {
@Override
public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
FirebaseUser user = firebaseAuth.getCurrentUser();
if(!TextUtils.isEmpty(sUser) && !TextUtils.isEmpty(sPass)){
signInVLogIn = true;
}else{
signInVLogIn = false;
}
if(user != null && signInVLogIn) {
}else{
//Toast.makeText(katiRoll.this, "Log In Failed", Toast.LENGTH_LONG).show();
}
}
};
sign.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
sUser = userEdit.getText().toString().trim();
sPass = passEdit.getText().toString().trim();
if(!TextUtils.isEmpty(sUser) && !TextUtils.isEmpty(sPass))
{
mAuth.signInWithEmailAndPassword(sUser, sPass).addOnCompleteListener(new OnCompleteListener<AuthResult>() {
@Override
public void onComplete(@NonNull Task<AuthResult> task) {
if(task.isSuccessful()){
mDatabaseRef.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
checkUserValidation(dataSnapshot, sUser);
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}else{
Toast.makeText(katiRoll.this, "User Login Doesn't Exist" , Toast.LENGTH_LONG).show();
}
}
});
}
}
});
reg.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
startActivity(new Intent(katiRoll.this, signUp.class));
}
});
}
private void checkUserValidation(DataSnapshot dataSnapshot, String emailForVer) {
Iterator iterator = dataSnapshot.getChildren().iterator();
while (iterator.hasNext())
{
DataSnapshot dataUser = (DataSnapshot)iterator.next();
if (dataUser.child("emailUser").getValue().toString().equals(emailForVer)){
if(dataUser.child("isVerified").getValue().toString().equals("unverified"))
{
Intent in = new Intent(katiRoll.this, Profile.class);
in.putExtra("USER KEY", dataUser.child("userKey").getValue().toString());
startActivity(in);
Log.d("USERKEY",dataUser.child("userKey").getValue().toString());
}
else{
startActivity(new Intent(katiRoll.this, welcome.class));
}
}
}
}
@Override
protected void onStart() {
super.onStart();
mAuth.addAuthStateListener(mAuthListener);
}
@Override
protected void onStop() {
super.onStop();
if(mAuthListener !=null){
mAuth.removeAuthStateListener(mAuthListener);
}
}
}
package com.example.akshay.katiroll.FirstScreen;
import android.content.Intent;
import android.graphics.Color;
import android.graphics.drawable.Drawable;
import android.support.annotation.NonNull;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.InputType;
import android.text.TextUtils;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.ImageView;
import android.widget.Toast;
import com.example.akshay.katiroll.SecondScreen.welcome;
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.Task;
import com.google.firebase.auth.AuthResult;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.example.akshay.katiroll.R;
import com.google.firebase.database.ValueEventListener;
import java.util.Iterator;
public class signUp extends AppCompatActivity {
EditText nUser, nPass;
Button registerBtn, backToMain;
ImageButton passVis;
FirebaseAuth mAuth;
FirebaseAuth.AuthStateListener mAuthListener;
DatabaseReference mDatabaseRef, mUserCheckData;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_sign_up);
nUser = (EditText) findViewById(R.id.nUser);
nPass = (EditText) findViewById(R.id.nPass);
registerBtn = (Button) findViewById(R.id.registerBtn);
backToMain = (Button) findViewById(R.id.backToMain);
passVis = (ImageButton)findViewById(R.id.passVis);
passVis.setImageResource(R.drawable.open);
passVis.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Drawable drawable = passVis.getDrawable();
if(drawable.getConstantState().equals(getResources().getDrawable(R.drawable.open,null).getConstantState())){
passVis.setImageResource(R.drawable.closed);
nPass.setInputType(InputType.TYPE_CLASS_TEXT | InputType.TYPE_TEXT_VARIATION_VISIBLE_PASSWORD);
}else{
passVis.setImageResource(R.drawable.open);
nPass.setInputType(InputType.TYPE_CLASS_TEXT | InputType.TYPE_TEXT_VARIATION_WEB_PASSWORD);
}
}
});
float Re = 255;
float Gr = 148;
float Bl = 0;
nUser.setTextColor(Color.rgb(Re, Gr, Bl));
nPass.setTextColor(Color.rgb(Re, Gr, Bl));
registerBtn.setTextColor(Color.rgb(Re, Gr, Bl));
backToMain.setTextColor(Color.rgb(Re, Gr, Bl));
mAuth = FirebaseAuth.getInstance();
mDatabaseRef = FirebaseDatabase.getInstance().getReference();
mUserCheckData = FirebaseDatabase.getInstance().getReference().child("User");
mAuthListener = new FirebaseAuth.AuthStateListener() {
@Override
public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
FirebaseUser user = firebaseAuth.getCurrentUser();
if (user != null) {
final String emailForVer = user.getEmail();
mUserCheckData.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
checkForValidation(dataSnapshot, emailForVer);
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
} else {
Log.d("TAG", "onAuthStateChanged:signed_out");
}
}
};
registerBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
final String nUserString, nPassString;
nUserString = (nUser.getText().toString().trim());
nPassString = (nPass.getText().toString().trim());
if(nPassString.length()>=6){
if (!TextUtils.isEmpty(nUserString) && !TextUtils.isEmpty(nPassString)) {
mAuth.createUserWithEmailAndPassword(nUserString, nPassString).addOnCompleteListener(new OnCompleteListener<AuthResult>() {
@Override
public void onComplete(@NonNull Task<AuthResult> task) {
if (task.isSuccessful()) {
DatabaseReference mChildDatabase = mDatabaseRef.child("Users").push();
String key_user = mChildDatabase.getKey();
mChildDatabase.child("isVerified").setValue("unverified");
mChildDatabase.child("userKey").setValue(key_user);
mChildDatabase.child("EmailUser").setValue(nUserString);
mChildDatabase.child("PasswordUser").setValue(nPassString);
Toast.makeText(signUp.this, "User Account Created, Check Email For Confirmation", Toast.LENGTH_LONG).show();
FirebaseUser user = mAuth.getCurrentUser();
if (user != null) {
user.sendEmailVerification();
}
startActivity(new Intent(signUp.this, Profile.class));
} else {
Toast.makeText(signUp.this, "Failed to create User Account", Toast.LENGTH_LONG).show();
}
}
});
} else {
Toast.makeText(signUp.this, "Failed to create User Account", Toast.LENGTH_LONG).show();
}
}else {
Toast.makeText(signUp.this, "Failed to create User Account", Toast.LENGTH_LONG).show();
}
}
});
backToMain.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
startActivity(new Intent(signUp.this, katiRoll.class));
}
});
}
private void checkForValidation(DataSnapshot dataSnapshot, String emailForVer) {
Iterator iterator = dataSnapshot.getChildren().iterator();
while (iterator.hasNext())
{
DataSnapshot dataUser = (DataSnapshot)iterator.next();
if (dataUser.child("emailUser").getValue().toString().equals(emailForVer)){
if(dataUser.child("isVerified").getValue().toString().equals("unverified"))
{
Intent in = new Intent(signUp.this, Profile.class);
in.putExtra("USER KEY", dataUser.child("userKey").getValue().toString());
startActivity(in);
Log.d("USERKEY",dataUser.child("userKey").getValue().toString());
}
else{
startActivity(new Intent(signUp.this, welcome.class));
}
}
}
}
protected void onStart() {
super.onStart();
mAuth.addAuthStateListener(mAuthListener);
}
@Override
protected void onStop() {
super.onStop();
if(mAuthListener !=null){
mAuth.removeAuthStateListener(mAuthListener);
}
}
}
package com.example.akshay.katiroll.SecondScreen;
import android.content.Intent;
import android.graphics.Color;
import android.support.annotation.NonNull;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import com.example.akshay.katiroll.FirstScreen.katiRoll;
import com.example.akshay.katiroll.R;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
public class welcome extends AppCompatActivity {
Button logOutBtn;
FirebaseAuth mAuth;
FirebaseAuth.AuthStateListener mAuthListener;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_welcome);
float Re = 255;
float Gr = 148;
float Bl = 0;
logOutBtn = (Button)findViewById(R.id.logOutBtn);
logOutBtn.setTextColor(Color.rgb(Re,Gr,Bl));
mAuth = FirebaseAuth.getInstance();
mAuthListener = new FirebaseAuth.AuthStateListener() {
@Override
public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
FirebaseUser user = firebaseAuth.getCurrentUser();
if(user !=null) {
}else{
}
}
};
logOutBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
mAuth.signOut();
finish();
startActivity(new Intent(welcome.this, katiRoll.class));
}
});
}
@Override
protected void onStart() {
super.onStart();
mAuth.addAuthStateListener(mAuthListener);
}
@Override
protected void onStop() {
super.onStop();
mAuth.removeAuthStateListener(mAuthListener);
}
}
推荐答案
告诉您的问题是引用做错了，您正在尝试在Firebase Database中获取不存在的内容
The problem that is telling to you is that you are doing wrong the reference, you are trying to get something inside Firebase Database that is not there
此行告诉您child("Users").child(KeyUser);在您当前的数据库结构中不存在
This line is telling you that the child("Users").child(KeyUser); does not exist in your current DB structure
要解决此问题，您应该查看数据库结构，然后重做参考.
To fix this you should see your databse structure and then redo your reference.
如果您发布Firebase数据库的照片，我将很高兴根据您的需求重构代码.
if you post a photo of your Firebase DB i will be glad to refactor your code to your needs.
在这里，您也弄错了USER_KEY
keyUser = getIntent().getStringExtra("USER_KEY");
要解决此问题，可以这样做
To fix this a short way would be doing this
keyUser = getIntent().getExtras().getString("USER_KEY");
您从哪里得到意图?如果您试图从另一个Activity中获取putExtra，则说明您做错了，请在此处设置额外的("USER_KEY");
you are geting an intent from where? if you are trying to get a putExtra from another Activity, you are doing it wrong, post where you are seting the extra ("USER_KEY");
Intent.getStringExtra()和Intent.getExtras()如果没有多余内容，则返回null，因此您需要在调用getString()
Intent.getStringExtra() and Intent.getExtras() returns null if there are no extras, so you need to check for that before trying to call getString()
一个快速检查附加内容的快速示例就是这个
one quick example to check for extras first would be this
String keyUser;
Bundle extras = getIntent().getExtras();
if(extras == null) {
Log.e("keyUser is null","");
} else {
keyUser= extras.getString("USER_KEY");
}
快乐的编码
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