dependencies添加
implementation 'com.jakewharton:butterknife:10.2.0'
annotationProcessor 'com.jakewharton:butterknife-compiler:10.2.0'

android{
    ...
compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
}

整体 apply plugin: 'com.android.application'
apply plugin: 'realm-android'
android {
compileSdkVersion 29
buildToolsVersion "29.0.2"
defaultConfig {
applicationId "com.ixuea.courses.myapplication"
minSdkVersion 16
targetSdkVersion 29
versionCode 1
versionName "1.0"
testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
}
}
compileOptions {
sourceCompatibility JavaVersion.VERSION_1_8
targetCompatibility JavaVersion.VERSION_1_8
}
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'androidx.appcompat:appcompat:1.1.0'
    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
    testImplementation 'junit:junit:4.12'

    implementation 'com.jakewharton:butterknife:10.2.0'
    annotationProcessor 'com.jakewharton:butterknife-compiler:10.2.0'

    androidTestImplementation 'androidx.test:runner:1.2.0'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
    implementation 'com.android.support:design:29'
}

之后在使用类添加上ButterKnife.bind(this);
查找控件
/**

• 登录按钮
  *
• 字段不能申明为private
  */

@BindView(R.id.bt_login)
Button bt_login;
绑定事件
/**

• 登录按钮点击
  */

@OnClick(R.id.bt_login)
public void bt_login() {
startActivity(LoginActivity.class);
}