Android Studio 3.0: buildToolsVersion not found in gradle files

Question

I recently installed new stable version of Android Studio (v3.0). Then created a new project and there was not any problem. But saw there is no buildToolsVersion field in the app-level build.gradle file. Even I searched all project files (CtrlShiftF), but didn't find anything!

What does this mean? And how can I determine what is the version of Build Tools in my app module?

---

build.gradle (Project):

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {

    repositories {
        google()
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.0.0'


        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        google()
        jcenter()
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

build.gradle (Module: app):

apply plugin: 'com.android.application'

android {
    compileSdkVersion 26
    defaultConfig {
        applicationId "ir.e900.androidstudio30"
        minSdkVersion 15
        targetSdkVersion 26
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'com.android.support:appcompat-v7:26.1.0'
    implementation 'com.android.support.constraint:constraint-layout:1.0.2'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.1'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
}

Answer 1

With the new android gradle plugin 3.x you no longer need to specify a version for the build tools (so, you can now remove the android.buildToolsVersion property).
By default, the plugin automatically uses the minimum required build tools version for the version of Android plugin you're using.

You can read more here.