Error:Execution failed for task ':app:processDebugResources'.
> com.android.ide.common.process.ProcessException: Failed to execute aapt

android {
    compileSdkVersion 25
    buildToolsVersion "25.0.2"
    defaultConfig {
        ...
        minSdkVersion 15
        targetSdkVersion 25
    }
}

compileSdkVersion 'android-O'
buildToolsVersion '26.0.0-rc1'
minSdkVersion 'O'

android {
  compileSdkVersion 'android-O'
  buildToolsVersion '26.0.0-rc1'

  defaultConfig {
    targetSdkVersion 'O'
  }
  ...
}

dependencies {
  compile 'com.android.support:appcompat-v7:26.0.0-alpha1'
}