Firebase 未解析的外部符号

Question

When I run my app in cocos2d, it prints the error:

2> Creating library C:\\Users\\Will\\Documents\\Projects\\Home\\proj.win32\\Debug.win32\\Home.lib and object C:\\Users\\Will\\Documents\\Projects\\Home\\proj.win32\\Debug.win32\\Home.exp 2>AppDelegate.obj : error LNK2001: unresolved external symbol "void * firebase::g_admob_initializer" (?g_admob_initializer@firebase@@3PAXA) 2>C:\\Users\\Will\\Documents\\Projects\\Home\\proj.win32\\Debug.win32\\Home.exe : fatal error LNK1120: 1 unresolved externals ========== Build: 1 succeeded, 1 failed, 4 up-to-date, 0 skipped ==========

I have no idea why. My app is literally the default cocos2d app, with the addition of the information in the firebase tutorial. All I did was include firebase\\admob.h and it causes the error. It doesn't cause the error when I include firebase\\app.h for some reason.

cocos2d verison: 3.15.1

NDK: v15

SDK: 26.0.0

It's saying unresolved external symbol, so I'm guessing that it has something to do with linking, but in my Android.mk, I link it.

app\\jni\\Android.mk

LOCAL_PATH := $(call my-dir)

# The path to the Firebase C++ SDK, in the project's root directory.
FIREBASE_CPP_SDK_DIR := ../../../firebase_cpp_sdk

APP_ABI := armeabi-v7a x86
STL := $(firstword $(subst _, ,$(APP_STL)))
FIREBASE_LIBRARY_PATH := $(FIREBASE_CPP_SDK_DIR)/libs/android/$(TARGET_ARCH_ABI)/$(STL)

include $(CLEAR_VARS)
LOCAL_MODULE := firebase_app
LOCAL_SRC_FILES := $(FIREBASE_LIBRARY_PATH)/libapp.a
LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH)/$(FIREBASE_CPP_SDK_DIR)/include
include $(PREBUILT_STATIC_LIBRARY)

include $(CLEAR_VARS)
LOCAL_MODULE := firebase_admob
LOCAL_SRC_FILES := $(FIREBASE_LIBRARY_PATH)/libadmob.a
LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH)/$(FIREBASE_CPP_SDK_DIR)/include
include $(PREBUILT_STATIC_LIBRARY)

include $(CLEAR_VARS)

$(call import-add-path,$(LOCAL_PATH)/../../../cocos2d)
$(call import-add-path,$(LOCAL_PATH)/../../../cocos2d/external)
$(call import-add-path,$(LOCAL_PATH)/../../../cocos2d/cocos)
$(call import-add-path,$(LOCAL_PATH)/../../../cocos2d/cocos/audio/include)

LOCAL_MODULE := MyGame_shared
LOCAL_MODULE_FILENAME := libMyGame

LOCAL_SRC_FILES := hellocpp/main.cpp \
               ../../../Classes/AppDelegate.cpp \
               ../../../Classes/HelloWorldScene.cpp

LOCAL_C_INCLUDES := $(LOCAL_PATH)/../../../Classes

# _COCOS_HEADER_ANDROID_BEGIN
# _COCOS_HEADER_ANDROID_END

LOCAL_STATIC_LIBRARIES := cocos2dx_static
LOCAL_STATIC_LIBRARIES += firebase_app
LOCAL_STATIC_LIBRARIES += firebase_admob

# _COCOS_LIB_ANDROID_BEGIN
# _COCOS_LIB_ANDROID_END

include $(BUILD_SHARED_LIBRARY)

$(call import-module,.)

# _COCOS_LIB_IMPORT_ANDROID_BEGIN
# _COCOS_LIB_IMPORT_ANDROID_END

build.gradle

import org.apache.tools.ant.taskdefs.condition.Os

apply plugin: 'com.android.application'

android {
    compileSdkVersion 22
    buildToolsVersion "25.0.0"

    defaultConfig {
        applicationId "com.call.home"
        minSdkVersion 14
        targetSdkVersion PROP_TARGET_SDK_VERSION
        versionCode 1
        versionName "1.0"

        externalNativeBuild {
            ndkBuild {
                if (!project.hasProperty("PROP_NDK_MODE") || PROP_NDK_MODE.compareTo('none') != 0) {
                    // skip the NDK Build step if PROP_NDK_MODE is none
                    targets 'MyGame'
                    arguments 'NDK_TOOLCHAIN_VERSION=4.9'
                    arguments 'APP_PLATFORM=android-'+PROP_TARGET_SDK_VERSION

                    def module_paths = [project.file("../../cocos2d").absolutePath,
                                        project.file("../../cocos2d/cocos").absolutePath,
                                        project.file("../../cocos2d/external").absolutePath]
                    if (Os.isFamily(Os.FAMILY_WINDOWS)) {
                        // should use '/'
                        module_paths = module_paths.collect {it.replaceAll('\\\\', '/')}
                        arguments 'NDK_MODULE_PATH=' + module_paths.join(";")
                    }
                    else {
                        arguments 'NDK_MODULE_PATH=' + module_paths.join(':')
                    }

                    arguments '-j' + Runtime.runtime.availableProcessors()
                    abiFilters.addAll(PROP_APP_ABI.split(':').collect{it as String})
                }
            }
        }
    }

    sourceSets.main {
        java.srcDir "src"
        res.srcDir "res"
        manifest.srcFile "AndroidManifest.xml"
        assets.srcDir "../../Resources"
    }

    externalNativeBuild {
        ndkBuild {
            if (!project.hasProperty("PROP_NDK_MODE") || PROP_NDK_MODE.compareTo('none') != 0) {
                // skip the NDK Build step if PROP_NDK_MODE is none
                path "jni/Android.mk"
            }
        }
    }

    signingConfigs {

       release {
            if (project.hasProperty("RELEASE_STORE_FILE")) {
                storeFile file(RELEASE_STORE_FILE)
                storePassword RELEASE_STORE_PASSWORD
                keyAlias RELEASE_KEY_ALIAS
                keyPassword RELEASE_KEY_PASSWORD
            }
        }
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
            if (project.hasProperty("RELEASE_STORE_FILE")) {
                signingConfig signingConfigs.release
            }

            externalNativeBuild {
                ndkBuild {
                    arguments 'NDK_DEBUG=0'
                }
            }
        }

        debug {
            externalNativeBuild {
                ndkBuild {
                    arguments 'NDK_DEBUG=1'
                }
            }
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile project(':libcocos2dx')
    compile 'com.google.firebase:firebase-ads:11.4.0'
}

apply plugin: 'com.google.gms.google-services'

Just to note, this is only in Visual Studio. Compiling it in command prompt or Android Studio doesn't create this problem.

Also noting, when I remove the line that says FIREBASE_APP_REGISTER_CALLBACKS_REFERENCE(admob) from the admob.h file, it works. However, I'm worried that it'd screw something up down the line so I'll hold of on that solution.

Answer 1

This is the error that results when you haven't added the firebase libraries to your project. You should verify by right-clicking on your project, then navigate to

Properties / Configuration Properties / Linker / Input / Additional Dependencies

and make sure you have (-d prefix for debug): firebase_admob-d.lib and any other firebase_***-d.lib that it depends on.