app下build.gradle文件添加代码红色标记如下
dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation 'com.android.support:appcompat-v7:+'
implementation 'com.android.support.constraint:constraint-layout:1.1.3'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'com.android.support.test:runner:1.0.2'
androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
implementation 'com.jakewharton:butterknife:8.8.1'
annotationProcessor'com.jakewharton:butterknife-compiler:8.8.1'
}
下载更新之后即可