Butterknife: Reports java.lang.NullPointerException after using 9.0.0-SNAPSHOT on gradle 3.0.1

[peter-zhijia-zheng]

the binded view is null after adding bindview in activity and fragment,

I'm using kotlin, so the code is as below in app gradle:
implementation "com.jakewharton:butterknife:$butterknife_version"
kapt "com.jakewharton:butterknife-compiler:$butterknife_version"

and as below in project gradle:
ext.butterknife_version = '9.0.0-SNAPSHOT'
dependencies {
classpath 'com.android.tools.build:gradle:3.0.1'
classpath "com.jakewharton:butterknife-gradle-plugin:$butterknife_version"
classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
}

[JakeWharton]

This is not enough information to diagnose a problem. Please provide a self-contained sample or failing test case.

[peter-zhijia-zheng]

Kotlin.zip
@JakeWharton

[peter-zhijia-zheng]

Anyone could help on this issue please? I haven't found the root cause, only me meet this issue?

[peter-zhijia-zheng]

this attached project doesn't popup NullPointerException, but still doesn't make sense, it must set version as 9.0.0-SNAPSHOT in project build.gradle, while must set version as 8.8.1 in app build.gradle, if all use 9.0.0-SNAPSHOT, the NullPointerException will happen, and if all use 8.8.1, the build error will happen
fuck.zip

[markproxy]

@zhijiazheng123 - You may be experiencing the same problem I reported on Stack Overflow: https://stackoverflow.com/q/48971092/315702

For us, the solution was to downgrade to Butterknife 8.5.1.

[peter-zhijia-zheng]

actually I've found the solution, no need to downgrade

[peter-zhijia-zheng]

done.zip

[peter-zhijia-zheng]

please help close this issue, thanks all!
@JakeWharton

[MohammadNsr]

@zhijiazheng123 what is the solution?

[hasnain-ahmad]

@zhijiazheng123 Kindly write down your solution. It will be helpful for the community.

[EdwardMuturi]

though this is closed, maybe it might help someone. It's a summary of @zhijiazheng123's solution

Bug cause : Mixing kotlin and java in the project (on my project)

on your project gradle:

buildscript {
    ext.kotlin_version = '1.3.31'
    ext.butterknife_version = '10.1.0'
    repositories {
        jcenter()
        mavenCentral()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.5.0-beta01'
        classpath 'com.google.gms:google-services:4.2.0'
        classpath "com.jakewharton:butterknife-gradle-plugin:$butterknife_version"
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

then on your gradle (app level)

dependencies {
//for java
 implementation 'com.jakewharton:butterknife:10.1.0'
    annotationProcessor 'com.jakewharton:butterknife-compiler:10.1.0'
//    kotlin 
    api "com.jakewharton:butterknife:$butterknife_version"
    kapt "com.jakewharton:butterknife-compiler:$butterknife_version"

this fixed my issue