布局xml中的资源，但编译器错误，显示“未找到”

Question

I have had some success with trying to get a sound synthesizer app to work. It worked fine on simulator, but always crash on the 8th time on my mobile phone ( OS 7.0 , simulator OS 6.0 , API level 21 , or OS 5.0 ). The error message was convoluted. I only remember the red-highlighted lines with "AudioFlinger" , and an error code with "AudioTrack" and "-20" .

I saw some advices here about changing the API level of the app to 21, but Android Studio only did 22, so that was what I changed. And that corrupted the whole thing. I am getting AAPT error on compile. The thing will not even start the emulator for try-run.

So I scrapped the whole thing, copy out the source codes (and layouts and other resources) and started a new project fresh, and copied back these files.

Now again, there is a compile error. There are multiple objects on XML that the Java source code reference to. All those lines with R.id.textview . All the "R" are now red with error, with the error message,

error: resource style/Base.V26.Widget.AppCompat.Toolbar not found.

This seems to be something completely "background" issue that I have no idea how to resolve, nor can I find solutions here. Any help is greatly appreciated.

Answer 1

This can cause trouble when there is a need to make new files, so clearing 'caches will clear the oldcache` and make Android Studio faster. Going to Build > Clean Project

Answer 2

清理您的项目或重建并重新启动android studio