모듈(앱 수준) Gradle 파일(일반적으로 <project>/<app-module>/build.gradle.kts 또는 <project>/<app-module>/build.gradle)에서 Android용 Firebase Authentication 라이브러리의 종속 항목을 추가합니다. 라이브러리 버전 관리 제어에는 Firebase Android BoM을 사용하는 것이 좋습니다.
dependencies{// Import the BoM for the Firebase platformimplementation(platform("com.google.firebase:firebase-bom:34.2.0"))// Add the dependency for the Firebase Authentication library// When using the BoM, you don't specify versions in Firebase library dependenciesimplementation("com.google.firebase:firebase-auth")}
Firebase BoM을 사용하지 않도록 선택한 경우에는 종속 항목 줄에 각 Firebase 라이브러리 버전을 지정해야 합니다.
앱에서 여러 Firebase 라이브러리를 사용하는 경우 모든 버전이 호환되도록 BoM을 사용하여 라이브러리 버전을 관리하는 것이 좋습니다.
dependencies{// Add the dependency for the Firebase Authentication library// When NOT using the BoM, you must specify versions in Firebase library dependenciesimplementation("com.google.firebase:firebase-auth:24.0.1")}
publicoverridefunonStart(){super.onStart()// Check if user is signed in (non-null) and update UI accordingly.valcurrentUser=auth.currentUserupdateUI(currentUser)}
@OverridepublicvoidonStart(){super.onStart();// Check if user is signed in (non-null) and update UI accordingly.FirebaseUsercurrentUser=mAuth.getCurrentUser();updateUI(currentUser);}
사용자가 앱에 로그인하면 사용자의 로그인 인증 정보(예: 사용자 이름과 비밀번호)를 인증 서버로 전송하세요. 서버가 사용자 인증 정보를 확인하여 정보가 유효하면 커스텀 토큰을 반환합니다.
인증 서버에서 커스텀 토큰을 받은 후 다음과 같이 이 토큰을 signInWithCustomToken에 전달하여 사용자를 로그인 처리합니다.
Kotlin
customToken?.let{auth.signInWithCustomToken(it).addOnCompleteListener(this){task->
if(task.isSuccessful){// Sign in success, update UI with the signed-in user's informationLog.d(TAG,"signInWithCustomToken:success")valuser=auth.currentUserupdateUI(user)}else{// If sign in fails, display a message to the user.Log.w(TAG,"signInWithCustomToken:failure",task.exception)Toast.makeText(baseContext,"Authentication failed.",Toast.LENGTH_SHORT,).show()updateUI(null)}}}
mAuth.signInWithCustomToken(mCustomToken).addOnCompleteListener(this,newOnCompleteListener<AuthResult>(){@OverridepublicvoidonComplete(@NonNullTask<AuthResult>task){if(task.isSuccessful()){// Sign in success, update UI with the signed-in user's informationLog.d(TAG,"signInWithCustomToken:success");FirebaseUseruser=mAuth.getCurrentUser();updateUI(user);}else{// If sign in fails, display a message to the user.Log.w(TAG,"signInWithCustomToken:failure",task.getException());Toast.makeText(CustomAuthActivity.this,"Authentication failed.",Toast.LENGTH_SHORT).show();updateUI(null);}}});
로그인이 성공하면 AuthStateListener에서 getCurrentUser 메서드로 사용자의 계정 데이터를 가져올 수 있습니다.
다음 단계
사용자가 처음으로 로그인하면 신규 사용자 계정이 생성되고 사용자가 로그인할 때 사용한 사용자 인증 정보(사용자 이름과 비밀번호, 전화번호 또는 인증 제공업체 정보)에 연결됩니다. 이 신규 계정은 Firebase 프로젝트의 일부로 저장되며 사용자의 로그인 방법에 관계없이 프로젝트 내 모든 앱에서 사용자를 식별하는 데 사용될 수 있습니다.
[[["이해하기 쉬움","easyToUnderstand","thumb-up"],["문제가 해결됨","solvedMyProblem","thumb-up"],["기타","otherUp","thumb-up"]],[["필요한 정보가 없음","missingTheInformationINeed","thumb-down"],["너무 복잡함/단계 수가 너무 많음","tooComplicatedTooManySteps","thumb-down"],["오래됨","outOfDate","thumb-down"],["번역 문제","translationIssue","thumb-down"],["샘플/코드 문제","samplesCodeIssue","thumb-down"],["기타","otherDown","thumb-down"]],["최종 업데이트: 2025-09-04(UTC)"],[],[],null,["You can integrate Firebase Authentication with a custom authentication system by\nmodifying your authentication server to produce custom signed tokens when a user\nsuccessfully signs in. Your app receives this token and uses it to authenticate\nwith Firebase.\n\nBefore you begin\n\n1. If you haven't already, [add Firebase to your Android project](/docs/android/setup).\n2. In your **module (app-level) Gradle file** (usually `\u003cproject\u003e/\u003capp-module\u003e/build.gradle.kts` or `\u003cproject\u003e/\u003capp-module\u003e/build.gradle`), add the dependency for the Firebase Authentication library for Android. We recommend using the [Firebase Android BoM](/docs/android/learn-more#bom) to control library versioning. \n\n ```carbon\n dependencies {\n // Import the BoM for the Firebase platform\n implementation(platform(\"com.google.firebase:firebase-bom:34.2.0\"))\n\n // Add the dependency for the Firebase Authentication library\n // When using the BoM, you don't specify versions in Firebase library dependencies\n implementation(\"com.google.firebase:firebase-auth\")\n }\n ```\n\n By using the [Firebase Android BoM](/docs/android/learn-more#bom),\n your app will always use compatible versions of Firebase Android libraries.\n *(Alternative)*\n Add Firebase library dependencies *without* using the BoM\n\n If you choose not to use the Firebase BoM, you must specify each Firebase library version\n in its dependency line.\n\n **Note that if you use *multiple* Firebase libraries in your app, we strongly\n recommend using the BoM to manage library versions, which ensures that all versions are\n compatible.** \n\n ```groovy\n dependencies {\n // Add the dependency for the Firebase Authentication library\n // When NOT using the BoM, you must specify versions in Firebase library dependencies\n implementation(\"com.google.firebase:firebase-auth:24.0.1\")\n }\n ```\n3. Get your project's server keys:\n 1. Go to the [Service Accounts](https://console.firebase.google.com/project/_/settings/serviceaccounts/adminsdk) page in your project's settings.\n 2. Click *Generate New Private Key* at the bottom of the *Firebase Admin SDK* section of the *Service Accounts* page.\n 3. The new service account's public/private key pair is automatically saved on your computer. Copy this file to your authentication server.\n\nAuthenticate with Firebase\n\n1. In your sign-in activity's `onCreate` method, get the shared instance of the `FirebaseAuth` object: \n\n Kotlin \n\n ```kotlin\n private lateinit var auth: FirebaseAuth\n // ...\n // Initialize Firebase Auth\n auth = Firebase.auth \n https://github.com/firebase/snippets-android/blob/b694d4dbd411d31be39655f47691c3e9f3529b03/auth/app/src/main/java/com/google/firebase/quickstart/auth/kotlin/CustomAuthActivity.kt#L27-L28\n ```\n\n Java \n\n ```java\n private FirebaseAuth mAuth;\n // ...\n // Initialize Firebase Auth\n mAuth = FirebaseAuth.getInstance();https://github.com/firebase/snippets-android/blob/b694d4dbd411d31be39655f47691c3e9f3529b03/auth/app/src/main/java/com/google/firebase/quickstart/auth/CustomAuthActivity.java#L48-L49\n ```\n2. When initializing your Activity, check to see if the user is currently signed in: \n\n Kotlin \n\n ```kotlin\n public override fun onStart() {\n super.onStart()\n // Check if user is signed in (non-null) and update UI accordingly.\n val currentUser = auth.currentUser\n updateUI(currentUser)\n }https://github.com/firebase/snippets-android/blob/b694d4dbd411d31be39655f47691c3e9f3529b03/auth/app/src/main/java/com/google/firebase/quickstart/auth/kotlin/CustomAuthActivity.kt#L33-L38\n ```\n\n Java \n\n ```java\n @Override\n public void onStart() {\n super.onStart();\n // Check if user is signed in (non-null) and update UI accordingly.\n FirebaseUser currentUser = mAuth.getCurrentUser();\n updateUI(currentUser);\n }https://github.com/firebase/snippets-android/blob/b694d4dbd411d31be39655f47691c3e9f3529b03/auth/app/src/main/java/com/google/firebase/quickstart/auth/CustomAuthActivity.java#L54-L60\n ```\n3. When users sign in to your app, send their sign-in credentials (for example, their username and password) to your authentication server. Your server checks the credentials and returns a [custom token](/docs/auth/admin/create-custom-tokens) if they are valid.\n4. After you receive the custom token from your authentication server, pass it to `signInWithCustomToken` to sign in the user: \n\n Kotlin \n\n ```kotlin\n customToken?.let {\n auth.signInWithCustomToken(it)\n .addOnCompleteListener(this) { task -\u003e\n if (task.isSuccessful) {\n // Sign in success, update UI with the signed-in user's information\n Log.d(TAG, \"signInWithCustomToken:success\")\n val user = auth.currentUser\n updateUI(user)\n } else {\n // If sign in fails, display a message to the user.\n Log.w(TAG, \"signInWithCustomToken:failure\", task.exception)\n Toast.makeText(\n baseContext,\n \"Authentication failed.\",\n Toast.LENGTH_SHORT,\n ).show()\n updateUI(null)\n }\n }\n }https://github.com/firebase/snippets-android/blob/b694d4dbd411d31be39655f47691c3e9f3529b03/auth/app/src/main/java/com/google/firebase/quickstart/auth/kotlin/CustomAuthActivity.kt#L44-L63\n ```\n\n Java \n\n ```java\n mAuth.signInWithCustomToken(mCustomToken)\n .addOnCompleteListener(this, new OnCompleteListener\u003cAuthResult\u003e() {\n @Override\n public void onComplete(@NonNull Task\u003cAuthResult\u003e task) {\n if (task.isSuccessful()) {\n // Sign in success, update UI with the signed-in user's information\n Log.d(TAG, \"signInWithCustomToken:success\");\n FirebaseUser user = mAuth.getCurrentUser();\n updateUI(user);\n } else {\n // If sign in fails, display a message to the user.\n Log.w(TAG, \"signInWithCustomToken:failure\", task.getException());\n Toast.makeText(CustomAuthActivity.this, \"Authentication failed.\",\n Toast.LENGTH_SHORT).show();\n updateUI(null);\n }\n }\n });https://github.com/firebase/snippets-android/blob/b694d4dbd411d31be39655f47691c3e9f3529b03/auth/app/src/main/java/com/google/firebase/quickstart/auth/CustomAuthActivity.java#L65-L82\n ```\n If sign-in succeeds, the `AuthStateListener` you can use the `getCurrentUser` method to get the user's account data.\n\nNext steps\n\nAfter a user signs in for the first time, a new user account is created and\nlinked to the credentials---that is, the user name and password, phone\nnumber, or auth provider information---the user signed in with. This new\naccount is stored as part of your Firebase project, and can be used to identify\na user across every app in your project, regardless of how the user signs in.\n\n- In your apps, you can get the user's basic profile information from the\n [`FirebaseUser`](/docs/reference/android/com/google/firebase/auth/FirebaseUser) object. See [Manage Users](/docs/auth/android/manage-users).\n\n- In your Firebase Realtime Database and Cloud Storage\n [Security Rules](/docs/database/security/user-security), you can\n get the signed-in user's unique user ID from the `auth` variable,\n and use it to control what data a user can access.\n\nYou can allow users to sign in to your app using multiple authentication\nproviders by [linking auth provider credentials to an\nexisting user account.](/docs/auth/android/account-linking)\n\nTo sign out a user, call [`signOut`](/docs/reference/android/com/google/firebase/auth/FirebaseAuth#signOut()): \n\nKotlin \n\n```kotlin\nFirebase.auth.signOut()https://github.com/firebase/snippets-android/blob/b694d4dbd411d31be39655f47691c3e9f3529b03/auth/app/src/main/java/com/google/firebase/quickstart/auth/kotlin/MainActivity.kt#L415-L415\n```\n\nJava \n\n```java\nFirebaseAuth.getInstance().signOut();https://github.com/firebase/snippets-android/blob/b694d4dbd411d31be39655f47691c3e9f3529b03/auth/app/src/main/java/com/google/firebase/quickstart/auth/MainActivity.java#L501-L501\n```"]]
