一切顺利。我尝试添加google_mobile_ads包到pubspec。添加此包后，每当我运行应用程序时，它都说minSdk版本不应小于19。
What went wrong:
Execution failed for task ':app:processDebugManifest'.
Manifest merger failed : uses-sdk:minSdkVersion 16 cannot be smaller than version 19 declared in library [:google_mobile_ads] D:AcademicMy WorkSoftware ProjectsMy Matesmy_matesbuildgoogle_mobile_adsintermediateslibrary_manifestdebugAndroidManifest.xml as the library might be using APIs not available in 16
Suggestion: use a compatible library with a minSdk of at most 16,
or increase this project's minSdk version to at least 19,
or use tools:overrideLibrary="io.flutter.plugins.googlemobileads" to force usage (may lead to runtime failures)
所以我更新了android/app/build中的minSdkVersion。从16岁到19岁。现在无论何时我运行代码它都会显示
A problem occurred evaluating root project 'firebase_auth'.
Could not find the firebase_core FlutterFire plugin, have you added it as a dependency in your pubspec?
虽然我已经更新了firebase_auth(^3.0.1),firebase_core (^ 1.4.0)升级到最新版本，但是没有任何效果。
看到很多相关的问题却没有解决方案，这很奇怪。任何遇到同样问题的人请分享如何克服它并成功重建应用程序。
在终端运行flutter clean
在此之后，再次运行flutter packages get以下载应用程序中的最新包。