java - 由于将空值传递给 FirebaseDatabase.getReference() 导致应用程序崩溃
问题描述
希望你能帮助我解决我的错误。我仍在开发我的登录应用程序,尽管有一些小错误,但到目前为止,该应用程序运行良好。现在,用户可以登录、登录和更改他的个人资料信息。在最后的步骤中,我还实现了删除用户信息的功能。同时,删除功能也起作用,以便从 FirebaseAuth 和 FirebaseRealtimeDatabase 中删除用户信息。删除用户信息后出现问题;应用程序崩溃。
日志猫:
09-17 16:56:31.108 19975-19975/com.example.login E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.login, PID: 19975
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.login/com.example.login.ProfileActivity}: java.lang.NullPointerException: Can't pass null for argument 'pathString' in FirebaseDatabase.getReference()
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2464)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2524)
at android.app.ActivityThread.access$900(ActivityThread.java:154)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1391)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:234)
at android.app.ActivityThread.main(ActivityThread.java:5526)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.NullPointerException: Can't pass null for argument 'pathString' in FirebaseDatabase.getReference()
at com.google.firebase.database.FirebaseDatabase.getReference(com.google.firebase:firebase-database@@19.0.0:164)
at com.example.login.ProfileActivity.onCreate(ProfileActivity.java:49)
at android.app.Activity.performCreate(Activity.java:6285)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1108)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2417)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2524)
at android.app.ActivityThread.access$900(ActivityThread.java:154)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1391)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:234)
at android.app.ActivityThread.main(ActivityThread.java:5526)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
简介活动:
public class ProfileActivity extends AppCompatActivity {
private TextView profilVorname,profilNachname,profilStrasse,profilHNr,profilPlz,profilStadt,profilLand;
private Button profilUpdate,PasswortUpdate;
private FirebaseAuth firebaseAuth;
private FirebaseDatabase firebaseDatabase;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_profile);
profilVorname= findViewById(R.id.textViewPVorname);
profilNachname=findViewById(R.id.textViewPNachname);
profilUpdate=findViewById(R.id.buttonProfilUpdate);
profilStrasse=findViewById(R.id.textViewPStrasse);
profilHNr=findViewById(R.id.textViewPHNr);
profilPlz=findViewById(R.id.textViewPPlz);
profilStadt=findViewById(R.id.textViewPStadt);
profilLand=findViewById(R.id.textViewPLand);
PasswortUpdate=findViewById(R.id.buttonPasswordUpdate);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setDisplayShowTitleEnabled(false);
firebaseAuth=FirebaseAuth.getInstance();
firebaseDatabase= FirebaseDatabase.getInstance();
DatabaseReference databaseReference= firebaseDatabase.getReference(firebaseAuth.getUid());
databaseReference.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
UserProfil userProfil=dataSnapshot.getValue(UserProfil.class);
profilVorname.setText(userProfil.getVorname());
profilNachname.setText(userProfil.getNachname());
profilStrasse.setText(userProfil.getStrasse());
profilHNr.setText(userProfil.getHnr());
profilPlz.setText(userProfil.getPlz());
profilStadt.setText(userProfil.getStadt());
profilLand.setText(userProfil.getLand());
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
Toast.makeText(ProfileActivity.this,"Database Error",Toast.LENGTH_SHORT).show();
}
});
profilUpdate.setOnClickListener(new View.OnClickListener(){
@Override
public void onClick(View view){
startActivity(new Intent(ProfileActivity.this,UpdateProfilActivity.class));
}
});
PasswortUpdate.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
startActivity(new Intent(ProfileActivity.this,UpdatePasswortActivity.class));
}
});
}
@Override
public boolean onOptionsItemSelected(@NonNull MenuItem item) {
switch(item.getItemId()){
case android.R.id.home:
onBackPressed();
}
return super.onOptionsItemSelected(item);
}
@Override
public void onBackPressed() {
super.onBackPressed();
startActivity(new Intent(ProfileActivity.this, NavActivity.class));
}
更新ProfilActivity:
public class UpdateProfilActivity extends AppCompatActivity {
private EditText newUserVorname, newUserNachname,newUserStrasse,newUserHnr,newUserPlz,newUserStadt,newUserLand;
private Button speichern;
private FirebaseAuth firebaseAuth;
private FirebaseDatabase firebaseDatabase;
private TextView loeschen;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_update_profil);
newUserVorname=findViewById(R.id.editTextVornameUpdate);
newUserNachname=findViewById(R.id.editTextNachnameUpdate);
newUserStrasse=findViewById(R.id.editTextStrasse);
newUserHnr=findViewById(R.id.editTextHNr);
newUserPlz=findViewById(R.id.editTextPlz);
newUserStadt=findViewById(R.id.editTextStadt);
newUserLand=findViewById(R.id.editTextLand);
speichern=findViewById(R.id.buttonSpeichern);
loeschen=findViewById(R.id.textViewLoeschen);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setDisplayShowTitleEnabled(false);
firebaseAuth= FirebaseAuth.getInstance();
firebaseDatabase= FirebaseDatabase.getInstance();
final DatabaseReference databaseReference= firebaseDatabase.getReference(firebaseAuth.getUid());
databaseReference.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
UserProfil userProfil=dataSnapshot.getValue(UserProfil.class);
newUserVorname.setText(userProfil.getVorname());
newUserNachname.setText(userProfil.getNachname());
newUserStrasse.setText(userProfil.getStrasse());
newUserHnr.setText(userProfil.getHnr());
newUserPlz.setText(userProfil.getPlz());
newUserStadt.setText(userProfil.getStadt());
newUserLand.setText(userProfil.getLand());
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
Toast.makeText(UpdateProfilActivity.this,"Database Error",Toast.LENGTH_SHORT).show();
}
});
speichern.setOnClickListener(new View.OnClickListener(){
@Override
public void onClick(View view){
String Vorname = newUserVorname.getText().toString();
String Nachname = newUserNachname.getText().toString();
String Strasse = newUserStrasse.getText().toString();
String HNr = newUserHnr.getText().toString();
String Plz = newUserPlz.getText().toString();
String Stadt = newUserStadt.getText().toString();
String Land = newUserLand.getText().toString();
UserProfil userProfil=new UserProfil(Vorname,Nachname,Strasse,HNr,Plz,Stadt,Land);
databaseReference.setValue(userProfil);
finish();
}
});
loeschen.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
FirebaseUser user= FirebaseAuth.getInstance().getCurrentUser();
String uid=firebaseAuth.getCurrentUser().getUid();
DatabaseReference databaseReference =firebaseDatabase.getReference(uid);
databaseReference.removeValue();
user.delete().addOnCompleteListener(new OnCompleteListener<Void>() {
@Override
public void onComplete(@NonNull Task<Void> task) {
if(task.isSuccessful()){
firebaseAuth.signOut();
startActivity(new Intent(UpdateProfilActivity.this, MainActivity.class));
finish();
}
}
});
}
});
}
@Override
public boolean onOptionsItemSelected(@NonNull MenuItem item) {
switch(item.getItemId()){
case android.R.id.home:
onBackPressed();
}
return super.onOptionsItemSelected(item);
}
}
解决方案
错误信息的核心是这样的:
所以看起来你在打电话getReference(null)
,这是不允许的。
在您共享的代码中,有两个调用getReference()
:
DatabaseReference databaseReference= firebaseDatabase.getReference(firebaseAuth.getUid());
和:
String uid=firebaseAuth.getCurrentUser().getUid();
DatabaseReference databaseReference =firebaseDatabase.getReference(uid);
在其中一种情况下,您传入的getReference(...)
值为null
. 我无法从您提供的信息中真正弄清楚哪个是,事实上我很惊讶第一个编译,因为FirebaseAuth
该类似乎没有getUid()
方法。
推荐阅读
- angular - 组件不加载 ng 属性 ionic
- android - 如何测量手机与被摄物体之间的距离?
- google-cloud-platform - 在 Google Cloud DataProc 上安排 cron 作业
- jquery - 如何在 jQuery 中从 JSON 文件中读取单个数据?
- php - Laravel 自定义控制器出现 404 错误
- ios - 如何确认来自 Firestore 的数据被快速附加?
- excel - 如何在excel中使用vba关闭特定名称的pdf文档
- angular - RxJs 订阅者不会在商店更改后立即更新
- linux - 如何启用/禁用/编辑 Alsa Audio 的 32 个通道?
- c++ - 这个构造函数是做什么的?