ButterKnife 8.x版本在AndroidStudio中的配置

按此方法配置，解决空指针。
1.Project的build.gradle文件中增加classpath

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:2.3.2'
        classpath 'com.neenbedankt.gradle.plugins:android-apt:1.8'

    }
}

allprojects {
    repositories {
        jcenter()
    }
}

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

2.在Module的build.gradle文件中增加plugin

apply plugin: ‘com.neenbedankt.android-apt’

3.在Module的build.gradle中的Dependencies中依赖包

compile ‘com.jakewharton:butterknife:8.6.0’
apt ‘com.jakewharton:butterknife-compiler:8.6.0’