Caused by: android.view.InflateException: Binary XML file line #0: Error inflating class android.support.v7.widget.ActionBarContextView

这个错误很摸不到头脑：

其实就是gradle 导包问题；

保证

implementation 'com.android.support:appcompat-v7:26.1.0'

和你用的控件一致：

compile 'com.android.support:recyclerview-v7:26.1.0'
dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])

    implementation 'com.android.support:appcompat-v7:26.1.0'
    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'
    compile 'com.android.support:recyclerview-v7:26.1.0'

}