Android Studio:如何使用片段正确登录Firebase [英] Android Studio: how to propperly sign in Firebase using fragments
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问题描述
我已经搜索了几个StackOverflow问题，例如:
I have searched several StackOverflow questions such as:
需要吗?在Android Firebase的每个活动中添加AuthStateListener?
应用程序崩溃，并出现java.lang.NullPointerException
FirebaseAuth.getCurrentUser()返回空值
android- java.lang.NullPointerException使用getCurrentUser firebase auth
应用程序在首次启动时崩溃使用FirebaseAuthentication
什么是NullPointerException，我该怎么办?修复吗?
最后是与我面临的问题最接近的问题:
And finally the closest question regarding to the problem I am facing:
在getCurrentUser()上获取空对象引用.getUid()
我还没有找到答案.在最后一个链接中，StackOverflow成员解释了 NullPointerException 的发生是因为在 getCurrentUser().getUid()== null的情况下，应用程序以某种方式忽略了从MainActivity到LoginActivity的重定向.并执行ChatFragment，其中发生 NullPointerException .
I have not found an answer yet. In the last link, a StackOverflow member explained that the NullPointerException happens because somehow the app ignores the redirection from the MainActivity to the LoginActivity in the case of getCurrentUser().getUid() == null and executes the ChatFragment, where the NullPointerException occurs.
我的应用程序在一开始就在Emulator上遇到了此类问题，但在某种程度上它在Emulator上可以正常工作.
My app had this kind of problem at the beginning on the Emulator, but somehow it works fine on the Emulator.
但是，现在，我尝试在物理设备中安装该应用程序，并且该应用程序崩溃了.我收到 NullPointerException ，因为该用户尚未登录.
But now, I tried to install the app in my physical device and the app is crashing. I get the NullPointerException because the user is not yet signed in.
我的应用程序类似于WhatsApp ChatApp.它具有带两个片段的滑动TabLayout.我的应用程序启动了MainActivity，在首次使用该应用程序时，应将AppUser重定向到LoginActivity.
My app is similar to WhatsApp ChatApp. It has sliding TabLayout with two fragments. My app launchs the MainActivity which should redirect the AppUser to LoginActivity in case of first use of the app.
这是我的MainActivity
Here is my MainActivity
public class MainPageActivity extends AppCompatActivity implements GroupListAdapter.DataChangeListener {
public static final int PERMISSIONS_MULTIPLE_REQUEST = 123;
private Toolbar mToolBar;
private ViewPager mViewPager;
private TabLayout mTabLayout;
private TabsAccessAdapter mTabsAcessAdapter;
private FirebaseAuth mAuth;
private DatabaseReference RootRef;
private String currentUserID;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_page);
FirebaseApp.initializeApp(this);
mAuth = FirebaseAuth.getInstance();
RootRef = FirebaseDatabase.getInstance().getReference();
mToolBar = (Toolbar) findViewById(R.id.main_page_toolbar);
setSupportActionBar(mToolBar);
getSupportActionBar().setTitle("MyApp");
mViewPager = (ViewPager) findViewById(R.id.tabs_pager);
mTabsAcessAdapter = new TabsAccessAdapter(getSupportFragmentManager());
mViewPager.setAdapter(mTabsAcessAdapter);
mTabLayout = (TabLayout) findViewById(R.id.tablayout);
mTabLayout.setupWithViewPager(mViewPager);
getPermissions();
}
private void getPermissions() {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
requestPermissions(new String[]{Manifest.permission.WRITE_CONTACTS,Manifest.permission.READ_CONTACTS,
Manifest.permission.WRITE_EXTERNAL_STORAGE,Manifest.permission.READ_EXTERNAL_STORAGE},PERMISSIONS_MULTIPLE_REQUEST);
}
}
@Override
protected void onStart() {
super.onStart();
Log.i("debinf mainpage", "onStart");
FirebaseAuth.getInstance().addAuthStateListener(new FirebaseAuth.AuthStateListener() {
@Override
public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
FirebaseUser currentUser = firebaseAuth.getCurrentUser();
if (currentUser == null) {
//Here is the place to redirect the AppUser to LoginActivity
sendUserToLoginActivity();
}else {
VerifyUserExistance();
}
}
});
}
private void VerifyUserExistance() {
String currentUserID = mAuth.getCurrentUser().getUid();
RootRef.child("user").child(currentUserID).addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
Toast.makeText(MainPageActivity.this, "Bem vindo(a)!", Toast.LENGTH_SHORT).show();
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
}
});
}
// Dealing with MENU > starts here
@Override
public boolean onCreateOptionsMenu(Menu menu) {
super.onCreateOptionsMenu(menu);
getMenuInflater().inflate(R.menu.options_menu,menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
super.onOptionsItemSelected(item);
if (item.getItemId() == R.id.main_logout_option) {
mAuth.signOut();
sendUserToLoginActivity();
}
if (item.getItemId() == R.id.main_settings_option) {
//sendUserToSettingsActivity();
Toast.makeText(this, "Settings from MainAct", Toast.LENGTH_SHORT).show();
}
return false;
}
private void sendUserToLoginActivity() {
Intent loginIntent = new Intent(MainPageActivity.this,LoginActivity.class);
loginIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
startActivity(loginIntent);
}
@Override
public void onDataSetChanged(String groupKeyFromSender, boolean addToCall) {
String tag = "android:switcher:" + R.id.tabs_pager + ":" + 1;
CallFragment rf = (CallFragment) getSupportFragmentManager().findFragmentByTag(tag);
rf.getDataFromGroupFragment(groupKeyFromSender, addToCall);
}
}
这是我的LoginActivity，第一次使用时应由MainActivity调用，但不是.
Here is my LoginActivity which should be called by MainActivity in the first usage, but it isn't.
public class LoginActivity extends AppCompatActivity {
private EditText mPhoneNumber, mCode;
private Button mSend;
private PhoneAuthProvider.OnVerificationStateChangedCallbacks mCallbacks;
String mVerificationId;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
FirebaseApp.initializeApp(this);
userIsLoggedIn();
mPhoneNumber = findViewById(R.id.phoneNumber);
mCode = findViewById(R.id.code);
mSend = findViewById(R.id.send);
mSend.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (mVerificationId != null) {
verifyPhoneNumberWithCode();
} else {
startPhoneNumberVerification();
}
}
});
mCallbacks = new PhoneAuthProvider.OnVerificationStateChangedCallbacks() {
@Override
public void onVerificationCompleted(PhoneAuthCredential phoneAuthCredential) {
sighInWithPhoneAuthCredential(phoneAuthCredential);
}
@Override
public void onVerificationFailed(FirebaseException e) {
}
@Override
public void onCodeSent(String verificationId, PhoneAuthProvider.ForceResendingToken forceResendingToken) {
super.onCodeSent(verificationId, forceResendingToken);
mVerificationId = verificationId;
mSend.setText("Enviar codigo");
}
};
}
private void verifyPhoneNumberWithCode(){
PhoneAuthCredential credential = PhoneAuthProvider.getCredential(mVerificationId, mCode.getText().toString());
sighInWithPhoneAuthCredential(credential);
}
private void sighInWithPhoneAuthCredential(PhoneAuthCredential phoneAuthCredential) {
FirebaseAuth.getInstance().signInWithCredential(phoneAuthCredential).addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
@Override
public void onComplete(@NonNull Task<AuthResult> task) {
if (task.isSuccessful()) {
//userIsLoggedIn();
final FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();
// I think add child named user and inside other child named userId = user.getUid()
if (user != null) {
// Do not forget to add database implementation in the gradle (module app)
final DatabaseReference mUserDB = FirebaseDatabase.getInstance().getReference().child("user").child(user.getUid());
mUserDB.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
if (!dataSnapshot.exists()) {
// if user has never loged in, add a new user
Map<String, Object> userMap = new HashMap<>();
userMap.put("phone", user.getPhoneNumber());
//userMap.put("name", user.getPhoneNumber());
userMap.put("name", "babaloo");
mUserDB.updateChildren(userMap);
}
userIsLoggedIn();
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
}
});
}
}
}
});
}
private void userIsLoggedIn() {
FirebaseAuth.getInstance().addAuthStateListener(new FirebaseAuth.AuthStateListener() {
@Override
public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
FirebaseUser user = firebaseAuth.getCurrentUser();
if (user != null) {
startActivity(new Intent(getApplicationContext(), MainPageActivity.class));
finish();
return;
}
}
});
}
private void startPhoneNumberVerification() {
PhoneAuthProvider.getInstance().verifyPhoneNumber(
mPhoneNumber.getText().toString(),60,
TimeUnit.SECONDS, this, mCallbacks);
}
}
这是发生 NullPointerException 的GroupFragment的onCreateView.
And here is the onCreateView of the GroupFragment where the NullPointerException happens.
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
view = inflater.inflate(R.layout.group_fragment, container, false);
groupTablePath = getContext().getFilesDir().getPath()+"/GroupDataBase/";
rootPath = Environment.getExternalStorageDirectory() + "/";
mAuth = FirebaseAuth.getInstance();
currentUser = mAuth.getCurrentUser().getUid();
GroupRef = FirebaseDatabase.getInstance().getReference().child("Group");
UserRef = FirebaseDatabase.getInstance().getReference().child("user");
StoreRef = FirebaseStorage.getInstance().getReference();
FloatingActionButton findUser = (FloatingActionButton) view.findViewById(R.id.addContact);
findUser.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
startActivity(new Intent(view.getContext(), FindUserActivity.class));
}
});
//getPermissions();
CreateRootFolder();
initializeRecyclerView();
loadGroupListDatabase();
populateTeamTableInternet();
OwnerGroupUploadClientListTable();
updateClientListInternet();
// Inflate the layout for this fragment
return view;
}
这部分错误
at com.example.aliton.myapp.Fragments.GroupFragment.onCreateView(GroupFragment.java:107)
对应于GroupFragment的onCreateView中的这一行代码:
corresponds to this line of the code in the onCreateView of the GroupFragment:
currentUser = mAuth.getCurrentUser().getUid();
这是致命错误:
02-09 20:24:10.950 24837-24837/com.example.aliton.myapp E/AndroidRuntime: FATAL EXCEPTION: main
java.lang.NullPointerException
at com.example.aliton.myapp.Fragments.GroupFragment.onCreateView(GroupFragment.java:107)
at android.support.v4.app.Fragment.performCreateView(Fragment.java:2439)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1460)
at android.support.v4.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1784)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1852)
at android.support.v4.app.BackStackRecord.executeOps(BackStackRecord.java:802)
at android.support.v4.app.FragmentManagerImpl.executeOps(FragmentManager.java:2625)
at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2411)
at android.support.v4.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManager.java:2366)
at android.support.v4.app.FragmentManagerImpl.execSingleAction(FragmentManager.java:2243)
at android.support.v4.app.BackStackRecord.commitNowAllowingStateLoss(BackStackRecord.java:654)
at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:146)
at android.support.v4.view.ViewPager.populate(ViewPager.java:1244)
at android.support.v4.view.ViewPager.populate(ViewPager.java:1092)
at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1622)
at android.view.View.measure(View.java:15294)
at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:665)
at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:447)
at android.view.View.measure(View.java:15294)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4818)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:143)
at android.view.View.measure(View.java:15294)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4818)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1421)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:712)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:605)
at android.view.View.measure(View.java:15294)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4818)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at android.view.View.measure(View.java:15294)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4818)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1421)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:712)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:605)
at android.view.View.measure(View.java:15294)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4818)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2432)
at android.view.View.measure(View.java:15294)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1872)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1115)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1296)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1013)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4245)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:725)
at android.view.Choreographer.doCallbacks(Choreographer.java:555)
at android.view.Choreographer.doFrame(Choreographer.java:525)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:711)
at android.os.Handler.handleCallback(Handler.java:615)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:153)
at android.app.ActivityThread.main(ActivityThread.java:5076)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:790)
at com.
感谢您的帮助.
推荐答案
这里有3个问题
- Auth侦听器是异步的，因此可以使用片段适配器创建竞争条件
- 您将在onCreate之后在onStart之后将auth侦听器附加到onStart上
- 如果未登录用户，则将使主逻辑屏幕成为入口点，然后它将返回登录状态.应该是向后的，您应该使登录名允许用户前进到下一个活动.
要修复1和2，您必须重构代码.
For fixing 1 and 2 you will have to refactor your code.
对于固定编号3，您应该在清单中将登录设置为默认活动.
For fixing number 3 you should set login as default activity in the manifest.
要修复您现在拥有的内容，请将其添加到主菜单的onCreate方法中
For fixing what you have now, add this in the onCreate method of the main
FirebaseApp.initializeApp(this);
mAuth = FirebaseAuth.getInstance();
RootRef = FirebaseDatabase.getInstance().getReference();
if (mAuth.getCurrentUser() == null) return;
返回该点将使代码跳转到onStary，在此您可以使用auth侦听器来使逻辑正常工作
Returning in that point will make the code jump to onStary where you have the auth listener making your logic work
这篇关于Android Studio:如何使用片段正确登录Firebase的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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