原因:无法找到带有哈希字符串“android-N"的目标

今天，我是 android studio 的新手.

Today, I'm newbie in android studio.

我已经更新了最新版本的andriod studio

I have updated the latest version of andriod studio

当我打开一个旧的项目并开始编译项目时，我检索了一个错误消息是原因:无法找到带有哈希字符串 'android-N' 的目标"

When I have opened an old projekct and started compiling the project I retrieve a error message that is "Cause: failed to find target with hash string 'android-N'"

What should I do in order to use this old project in the updated android studio?

谢谢！

来自文件 build.gradle 的源代码

Sourcecode from the file build.gradle

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

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:2.1.0'

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

allprojects {
    repositories {
        jcenter()
    }
}

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