Android 弄明白了主要的问题是什么，甚至我下载了aapt2-3.2.1-4818971-windows.jar，但是这个文件应该粘贴到哪里呢？

确保build.gradle文件中有google（）存储库

Could not find com.android.tools.build:aapt2:3.2.1-4818971.
Searched in the following locations:
    file:/C:/Users/Anand/AppData/Local/Android/Sdk/extras/m2repository/com/android/tools/build/aapt2/3.2.1-4818971/aapt2-3.2.1-4818971.pom
    file:/C:/Users/Anand/AppData/Local/Android/Sdk/extras/m2repository/com/android/tools/build/aapt2/3.2.1-4818971/aapt2-3.2.1-4818971-windows.jar
    file:/C:/Users/Anand/AppData/Local/Android/Sdk/extras/google/m2repository/com/android/tools/build/aapt2/3.2.1-4818971/aapt2-3.2.1-4818971.pom
    file:/C:/Users/Anand/AppData/Local/Android/Sdk/extras/google/m2repository/com/android/tools/build/aapt2/3.2.1-4818971/aapt2-3.2.1-4818971-windows.jar
    file:/C:/Users/Anand/AppData/Local/Android/Sdk/extras/android/m2repository/com/android/tools/build/aapt2/3.2.1-4818971/aapt2-3.2.1-4818971.pom
    file:/C:/Users/Anand/AppData/Local/Android/Sdk/extras/android/m2repository/com/android/tools/build/aapt2/3.2.1-4818971/aapt2-3.2.1-4818971-windows.jar
    https://jcenter.bintray.com/com/android/tools/build/aapt2/3.2.1-4818971/aapt2-3.2.1-4818971.pom
    https://jcenter.bintray.com/com/android/tools/build/aapt2/3.2.1-4818971/aapt2-3.2.1-4818971-windows.jar
Required by:
    project :slideMenuLibrary

buildscript{
存储库{
google（）//那不是依赖关系，那是存储库。但是，不要使用alpha版本。使用gradle的最新稳定版本：
3.2.1
buildscript {
  repositories {
      google() // <----
      jcenter()
  }
  dependencies {
      classpath 'com.android.tools.build:gradle:3.2.1'
  }
} 
allprojects {
  repositories {
      google() // <----
      jcenter()
}