title: How to change build tools version in Android Studio 3.0.1?
body: <p>I just upgraded my Android studio from 2.3 to 3.0.1. But I get this error message(I have already installed API 27 ) and don't know how to fix it, because I couldn't find the the build tools version in new version of android studio!</p>
  
  <pre><code>Error:Failed to find Build Tools revision 26.0.2 &lt;a href="install.build.tools"&gt;Install Build Tools 26.0.2 and sync project&lt;/a&gt;
  </code></pre>
  
  <p>The gradle files are changed, also the project structure has only one tab!</p>
  
  <p>Edit:
      this is the content of `app/build.gradle:</p>
  
  <pre><code>apply plugin: 'com.android.application'
  
  android {
      compileSdkVersion 27
      defaultConfig {
          applicationId "com.m.finalocr"
          minSdkVersion 21
          targetSdkVersion 27
          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-v7:27.0.2'
      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'
  }
  </code></pre>
  
  <p>As you can see, there is no <code>buildToolsVersion</code> in it. So, why my android studio looks for this specific version(26) of that when I have the 27 version installed on my computer? Also, where can I see the <code>buildToolsVersion "26.0.2" and change it to</code>buildToolsVersion "27.0.3" ` ?</p>