not suppert

We face the same problem, this is probably related to https://developer.android.com/studio/preview/features/new-android-plugin-migration.html#variant_api

Error:FAILURE: Build failed with an exception.

• What went wrong:
  Execution failed for task ':app:javaPreCompileDebug'.

Annotation processors must now be declared explicitly. The following dependencies in the compile classpath are found to contain annotation processors. Please add them to the annotationProcessor configuration.
- butterknife-7.0.1.jar
Alternatively, set android.defaultConfig.javaCompileOptions.annotationProcessorOptions.includeCompileClasspath = true to continue with the previous behavior. Note that this option is deprecated and will be removed in the future.
See https://developer.android.com/r/tools/annotation-processor-error-message.html for more details.

• Try:
  Run with --stacktrace option to get the stack trace. Run with --debug option to get more log output.

I'm using the following, with the following error:
root build.gradle:

dependencies {
    classpath 'com.jakewharton:butterknife-gradle-plugin:8.6.0'
    ...
}

lib/build.gradle:

apply plugin: 'com.jakewharton.butterknife'
...
def butterknife = "8.6.0"
implementation "com.jakewharton:butterknife:${butterknife}" //woo new Gradle API!
annotationProcessor "com.jakewharton:butterknife-compiler:${butterknife}"

Stacktrace from gradlew:

Caused by: java.lang.NoSuchMethodError: com.android.build.gradle.api.BaseVariant.getOutputs()Ljava/util/List;
        at butterknife.plugin.ButterKnifePlugin$applyPlugin$1.execute(ButterKnifePlugin.kt:27)
        at butterknife.plugin.ButterKnifePlugin$applyPlugin$1.execute(ButterKnifePlugin.kt:15)
        ...

It looks like ButterKnifePlugin.kt #27 is the offending line - it calls variant.outputs.forEach, but the new Android Gradle 3.0 plugin requires variants.outputs.all (source)

I'm not really a Gradle expert - is that really the extent of the change that's necessary?

I've also tried the 8.6.1-SNAPSHOT - same issue

Did anyone find a workaround to this yet?

Add
maven {
url 'https://maven.google.com'
}

Then you'll got an update for alpha2.

I have found a workaround :
Using the 8.4.0 version ( classpath 'com.jakewharton:butterknife-gradle-plugin:8.4.0' )

But it doesn't resolve the compatibility issue with "Feature Module" :
Error:Butterknife plugin can only be applied to android projects

I understand the project can not depend on an unstable version of the gradle plugin (per comment on #964).

So, as far as I see, we could:

1. Fork the project until a new version address the problem.
2. Wait until the gradle plugin gets out of alpha, then beta and reach at least a RC version.

Any other option?

Moving the butterknife plugin locally into our projects buildSrc is working for me as a workaround

@denizmveli I tried your workaround, In my case, it did not work for "Feature Module"

@Aks-4125 It worked. Thanks

compile 'com.jakewharton:butterknife:8.8.1'
annotationProcessor 'com.jakewharton:butterknife-compiler:8.8.1'

It worked.Thanks

you can use gradle 2.3.3.My project can't work if I use gradle 3.0.0.But it works when I use gradle 2.3.3.

@AndSync @SaudM remove apply plugin: 'com.jakewharton.butterknife' may be worked，but there will be NullPointerException. eg.

yes i'm using Android studio 3.1 Canary 6. It can't find the butter knife jar though gradle.

Some additional info from our post-mortem after solving this bug, in case it may contain useful info to help someone else solve it as well:

Problem encountered when upgrading from Android Studio 2.3.2 to Android Studio 3.0.1:

TL;DR:
Don't upgrade to Android Studio 3.0, unless also add this to your app/build.gradle file:

android {
    defaultConfig {
        javaCompileOptions {
            annotationProcessorOptions {
                includeCompileClasspath true // NB! see doc below
            }
        }
    }

Alternatively, you could instead upgrade the ButterKnife library, but for us that entailed a lot of refactor renaming, and an unknown amount of extra upgrade work, so it was not desirable at this time.

Problem:

• App crashes on Android mobiles on startup.
  Line 577 in our TimeLineUI.java gives a NullPointerException, because:
  Line 101 in our TimeLineUI.java uses @InjectView to instantiate dashboardBackground, but it is suddenly null at the time it is called.

NB: We didn't make any changes to the codebase. Only the automatic changes Android Studio made to the build.gradle when building in the new Android Studio version.

The stacktrace for the NullPointerException we got, similar to @ZQiang94 :

E/AndroidRuntime: FATAL EXCEPTION: main
                  Process: projectname.staging, PID: 6570
                  java.lang.RuntimeException: Unable to start activity ComponentInfo{projectname.staging/projectname.ui.TimeLineUI}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.RelativeLayout.setVisibility(int)' on a null object reference
                      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2924)
                      at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2985)
                      at android.app.ActivityThread.-wrap14(ActivityThread.java)
                      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1635)
                      at android.os.Handler.dispatchMessage(Handler.java:102)
                      at android.os.Looper.loop(Looper.java:154)
                      at android.app.ActivityThread.main(ActivityThread.java:6692)
                      at java.lang.reflect.Method.invoke(Native Method)
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1468)
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1358)
                   Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.RelativeLayout.setVisibility(int)' on a null object reference
                      at projectname.ui.TimeLineUI.toggleSplashScreen(TimeLineUI.java:577)
                      at projectname.ui.TimeLineUI.initSplashscreen(TimeLineUI.java:553)
                      at projectname.ui.TimeLineUI.onCreate(TimeLineUI.java:178)

Cause and explanation:

The @InjectView annotations in the source code is used by the ButterKnife library to instantiate objects.

If the instantiation isn't done properly then the app crashes on startup, on line 577.

ButterKnife used to instantiate these properly in Android Studio 2.3.2 (where the build would succeed).

We installed Android Studio 3.0 first, and tried to build. It made some changes to build.gradle:

build.gradle (Project: projectname) build script dependencies was upgraded:

-        classpath 'com.android.tools.build:gradle:2.3.3'
+        classpath 'com.android.tools.build:gradle:3.0.1'

Android Studio 3.0 needs annotation processors specifically defined, for annotations to work correctly:
https://developer.android.com/studio/build/gradle-plugin-3-0-0-migration.html?utm_source=android-studio#annotationProcessor_config

If we try to fix it by simply adding this dependency in the app/build.gradle, to match the butterknife version we use:
annotationProcessor 'com.jakewharton:butterknife-compiler:5.5.1'
Then we run into the issue that butterknife-compiler 5.5.1 JAR file doesn't exist (probably the same problem @configurer encountered), because ButterKnife didn't include butterknife-compiler until ButterKnife version 8.2.0.

We could upgrade to ButterKnife 8.2.0 or later.
But ButterKnife uses @BindView in the latest version, instead of @InjectView. So if we upgrade ButterKnife to 8.2.0 or later, then we have to rename all the instances of @InjectView to @BindView in 100+ places in 17+ files, and potentially have to make other changes too. The rename refactoring was attempted, but the upgrade entails we have to change other things in the codebase too. We are uncertain of the is uncertain of the size of the scope, and deems that it could take a while. So it is not worth it, at this time.

So the initial conclusion is that we:

• Postpone upgrading to Android Studio 3.0 and/or upgrading the ButterKnife library indefinitely, until we absolutely need to do it. If so, use the suggestion by songhaonangit: Android studio 3.0 butterknife error #963 (comment)

• Quick fix: Downloaded Android Studio 2.3.2 instead, and verified the build works there, when using classpath 'com.android.tools.build:gradle:2.3.2'

Solution:

Was actually able to use Android Studio 3.0 with this small change to the app/build.gradle file (to make it work like in Android Studio 2.3.2):

android {
...
    defaultConfig {
...
        javaCompileOptions {
            annotationProcessorOptions {
                // TODO:
                // includeCompileClasspath should be set to false in future versions, since this option is deprecated and will be removed.
                // This is to increase speed of compilation: https://developer.android.com/studio/build/gradle-plugin-3-0-0-migration.html?utm_source=android-studio#annotationProcessor_config
                // But when it's set to false be wary of any NullPointerException errors it may cause because of ButterKnife's @InjectView.
                includeCompileClasspath true
            }
        }
    }

Now this is why it's worth to regularly spend time on updating dependencies.

@AndSync any reason why the apply plugin: 'com.jakewharton.butterknife'caused the issue?

I found this solution
Change:
compile 'com.jakewharton:butterknife:8.+.+'
into
annotationProcessor 'com.jakewharton:butterknife:8.+.+'
it worked for me

pry(main)> "annotationProcessor 'com.jakewharton:butterknife:8.+.+'" == "annotationProcessor 'com.jakewharton:butterknife:8.+.+'"
=> true

🤔

I was solving the 'spot the difference' puzzle by user @bqhub30

But I am also stuck with unable to build ButterKnife !

Error:
Annotation processors must now be declared explicitly. The following dependencies in the compile classpath are found to contain annotation processors. Please add them to the annotationProcessor configuration.

I found this solution:

android {
        ...
        defaultConfig {
            ...
            //config
            javaCompileOptions { annotationProcessorOptions { includeCompileClasspath = true } }
    }
    ...
}

implementation 'com.jakewharton:butterknife:8.8.1'
annotationProcessor 'com.jakewharton:butterknife-compiler:8.8.1'

a workaround, tested.

Thanks work for me, Specs build gradle:

buildscript {
    repositories {
        google()
        jcenter()
        
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.4.2'
        
        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        google()
        jcenter()
        
    }
}

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

follow instruction for GitHub repository which worked for me 100% with the latest version here URL: https://github.com/JakeWharton/butterknife

No meu caso foi apenas o antivírus (KasperSky) que estava filtrando as conexões criptografadas, após desativar voltou ao normal.