android.support.v7.widget.toolbar类未显示在我的任何新项目中？

我已经输入了Toolbar和IntelliSense给我类参考

import android.widget.Toolbar但不显示
android.support.v7.widget.toolbar

我已经创建了多个新项目，但仍然无法工作。我以前使用的
android.support.v7.widget.toolbar的项目运行良好

我最近从SDK管理器中添加了安卓N包。这可能是一个原因

梯度（项目）设置：

// 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:1.5.0'

        // 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
}

apply plugin: 'com.android.application'

android {
    compileSdkVersion 23
    buildToolsVersion "23.0.2"

    defaultConfig {
        applicationId "harry.com.myapplication"
        minSdkVersion 15
        targetSdkVersion 23
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:appcompat-v7:23.2.1'
}

Gradle应用程序设置：

// 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:1.5.0'

        // 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
}

apply plugin: 'com.android.application'

android {
    compileSdkVersion 23
    buildToolsVersion "23.0.2"

    defaultConfig {
        applicationId "harry.com.myapplication"
        minSdkVersion 15
        targetSdkVersion 23
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:appcompat-v7:23.2.1'
}

调用
compile'com.android.support:appcompat-v7:23.0.0'
set classpath
com.android.tools.build:gradle:2.0.0-beta7
我收到此错误
警告：需要gradle版本2.10。目前的版本是2.8。如果使用gradle包装器，请尝试在/Volumes/BOOTCAMP/Android_Projects/MyApplication2/gradle/wrapper/gradle-wrapper.properties中编辑gradle-2.10-all.zip的distributionUrl，但仍无法使用gradle 2.12