Question

我有4个片段。以下是导航流程

[片段1]-> [片段2]-> [片段3]

[片段4]-> [片段3]

如果用户在按回[Fragment 3]时从4转到片段3（即[Fragment 4]-> [Fragment 3]），则应该转到[Fragment 1]。

我认为，如果我能够找到先前的片段，那么将很容易重定向到[fragment 1]。有什么办法可以找到以前被替换的片段？

我尝试了fragmentManager.getBackStackEntryAt（fragmentManager.backStackEntryCount-1），但是只显示了当前片段的一个条目。

片段管理器看起来像这样。

onBackPressed of Fragment 3中，我做了这样的事情。

override fun onBackPressed(): Boolean {
    args.host.hideKeyboard()

    if (redirectToProductList) {
        args.host.activity?.let {
            if (it.supportFragmentManager.popBackStackImmediate(null, FragmentManager.POP_BACK_STACK_INCLUSIVE)) {
                openFirstFragment(it, SupportFragment(MainActivity.SalesRepProduct))
                return true
            }
        }
    }
    return args.host.childFragmentManager.popBackStackImmediate()
}

Answer 1

我已经发布了此问题，请在此处找到答案

来源：

Link

# project/vuedj/settings.py
BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
PROJECT_PATH = os.path.realpath(os.path.dirname(__file__))
SECRET_KEY = persisted_settings.SECRET_KEY
DEBUG = True
ALLOWED_HOSTS = ['127.0.0.1', 'localhost']
CORS_ORIGIN_ALLOW_ALL = True
CORS_URLS_REGEX = r'^/api/.*$'
CORS_ALLOW_CREDENTIALS = True

# Application definition

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'django.contrib.sites',
    'rest_framework',
    'rest_framework.authtoken',
    'corsheaders',
    'allauth',
    'allauth.account',
    'allauth.socialaccount',
    'allauth.socialaccount.providers.github',
    'rest_auth',
    'rest_auth.registration',
    'sceneries',
    'accounts',
    'api',
    'app',
]

EMAIL_BACKEND = 'django.core.mail.backends.filebased.EmailBackend'
EMAIL_FILE_PATH = 'app-messages'
SITE_ID = 1

AUTH_USER_MODEL = 'accounts.User'
ACCOUNT_USER_MODEL_USERNAME_FIELD = 'username'
ACCOUNT_AUTHENTICATION_METHOD = 'username_email'

ACCOUNT_EMAIL_REQUIRED = True
ACCOUNT_EMAIL_VERIFICATION = 'none'
ACCOUNT_UNIQUE_EMAIL = True
ACCOUNT_USERNAME_REQUIRED = True
ACCOUNT_USER_EMAIL_FIELD = 'email'
ACCOUNT_LOGOUT_ON_GET = True
ACCOUNT_FORMS = {"login": "accounts.forms.UserLoginForm"}
LOGIN_REDIRECT_URL = 'home'
LOGIN_URL = 'api/v1/accounts/login/'

CSRF_COOKIE_NAME = "csrftoken"

REST_AUTH_SERIALIZERS = {
    "USER_DETAILS_SERIALIZER": "accounts.serializers.CustomUserDetailsSerializer",
    "LOGIN_SERIALIZER": "accounts.serializers.CustomUserLoginSerializer",
    "PASSWORD_RESET_SERIALIZER": "accounts.serializers.CustomPasswordResetSerializer"
}

REST_AUTH_REGISTER_SERIALIZERS = {
    "REGISTER_SERIALIZER": "accounts.serializers.CustomRegisterSerializer",
}

# Following is added to enable registration with email instead of username
AUTHENTICATION_BACKENDS = (
    # Needed to login by username in Django admin, regardless of `allauth`
    "django.contrib.auth.backends.ModelBackend",
    # `allauth` specific authentication methods, such as login by e-mail
    "allauth.account.auth_backends.AuthenticationBackend",
)

MIDDLEWARE = [
    'corsheaders.middleware.CorsMiddleware',
    'django.middleware.security.SecurityMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.common.CommonMiddleware',
    'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
    'django.middleware.clickjacking.XFrameOptionsMiddleware',
]

ROOT_URLCONF = 'vuedj.urls'

TEMPLATES = [
    {
        'BACKEND': 'django.template.backends.django.DjangoTemplates',
        'DIRS': [
            'templates/',
            'templates/emails/'
        ],
        'APP_DIRS': True,
        'OPTIONS': {
            'context_processors': [
                'django.template.context_processors.debug',
                'django.template.context_processors.request',
                'django.contrib.auth.context_processors.auth',
                'django.contrib.messages.context_processors.messages',
            ],
        },
    },
]

WSGI_APPLICATION = 'vuedj.wsgi.application'

try:
        DATABASES = persisted_settings.DATABASES
except AttributeError:
        DATABASES = {
                'default': {
                        'ENGINE': 'django.db.backends.sqlite3',
                        'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),
                }
        }

REST_FRAMEWORK = {
    'DEFAULT_AUTHENTICATION_CLASSES': [
        'rest_framework.authentication.TokenAuthentication',
    ],
    'DEFAULT_PERMISSION_CLASSES': [
        'rest_framework.permissions.IsAuthenticated',
    ]
}

AUTH_PASSWORD_VALIDATORS = [
    {
        'NAME': 'django.contrib.auth.password_validation.UserAttributeSimilarityValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.MinimumLengthValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.CommonPasswordValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.NumericPasswordValidator',
    },
]

LANGUAGE_CODE = 'en-us'
TIME_ZONE = 'UTC'
USE_I18N = True
USE_L10N = True
USE_TZ = True

STATICFILES_DIRS = (
    os.path.join(BASE_DIR, 'static'),
)
STATIC_ROOT = os.path.join(BASE_DIR, '../staticfiles/static')
MEDIA_ROOT = os.path.join(BASE_DIR, '../staticfiles/mediafiles')
STATIC_URL = '/static/'
MEDIA_URL = '/media/'

TEST_RUNNER = 'django_nose.NoseTestSuiteRunner'

NOSE_ARGS = [
    '--with-coverage',
    '--cover-package=app',  # For multiple apps use '--cover-package=foo, bar'
]

Answer 2

我解决了这个问题。我没有在片段中添加片段。

fragmentManager.beginTransaction()
            .addToBackStack(newFragment.javaClass.name)
            .commit()

然后我找到了以前的片段，像这样。

override fun onBackPressed(): Boolean {
    args.host.hideKeyboard()
    val index = args.host.fragmentManager.backStackEntryCount - 2
    if (index >= 0) {
        val prevFrag = args.host.fragmentManager.getBackStackEntryAt(index)
        if (prevFrag.name == SearchContainerPresenter::class.java.name)
            args.host.activity?.let {
                if (it.supportFragmentManager.popBackStackImmediate(null, FragmentManager.POP_BACK_STACK_INCLUSIVE)) {
                    openFirstFragment(it, SupportFragment(MainActivity.SalesRepProduct))
                    return true
                }
            }
        else
            return args.host.childFragmentManager.popBackStackImmediate()
    }
    return args.host.childFragmentManager.popBackStackImmediate()
}

Answer 3

您可以像这样使用监听器

supportFragmentManager.addOnBackStackChangedListener {
    val fragment = supportFragmentManager.findFragmentById(R.id.container)
    //Write your logic here
}

查找先前的活动片段

3 个答案: