errors with gradle in android studio

Question

I am trying to build the project and run it in my google glass but when ever i am trying to build it is showing that

Error:(20, 0) Gradle DSL method not found: 'runProguard()' Possible causes:

The project 'gdk-stopwatch-sample' may be using a version of Gradle that does not contain the method. Gradle settings

The build file may be missing a Gradle plugin. Apply Gradle plugin

but i have installed the latest gradle plugin i.e 2.13, changed the classpath in build.gradle to 'com.android.tools.build:gradle:2.1.3', gradle-wrapper properties to (distributionUrl=https://services.gradle.org/distributions/gradle-2.13-all.zip), deleted the .gradle file in Users but it keeps on appearing again and again, and also in settings I marked as offline work, service directory path keeps on appearing though

Updated Manifest

<?xml version="1.0" encoding="utf-8"?>

<uses-sdk android:minSdkVersion="19" android:targetSdkVersion="19" />

<application>
    <uses-library android:name="android.test.runner" />
</application>

<instrumentation android:name="android.test.InstrumentationTestRunner"
                 android:targetPackage="com.google.android.glass.sample.stopwatch"
                 android:handleProfiling="false"
                 android:functionalTest="false"
                 android:label="Tests for com.google.android.glass.sample.stopwatch"/>

Answer 1

It happens because the gradle plugin for Android 2.1.3 doesn't exist.
Don't confuse the gradle version with the gradle plugin.

Use

buildscript {

    repositories {
        jcenter()
    }

    dependencies {
        classpath 'com.android.tools.build:gradle:2.1.0'
    }
}

About the runProguard change your script with:

release {
    minifyEnabled true 
    proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}