ButterKnife 8.0.1 not working

问题

I am using butterknife 8.0.1, but a nullpointerexception is appearing.

This line is on my build.grade file: compile 'com.jakewharton:butterknife:8.0.1'

this is my Main Class: (I wrote the includes properly)

import butterknife.BindView;
import butterknife.ButterKnife;

public class MainActivity extends BaseActivity {

    @BindView(R.id.MainScreenTextView) TextView mainText;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        ButterKnife.bind(this);

        **mainText.setText("Butter knife is working fine");**
    }

and this is MainActivity.xml:

<android.support.design.widget.AppBarLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:theme="@style/AppTheme.AppBarOverlay">

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:background="?attr/colorPrimary"
        app:popupTheme="@style/AppTheme.PopupOverlay" />

</android.support.design.widget.AppBarLayout>

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center_vertical"
    android:orientation="vertical">

    <TextView
        android:id="@+id/MainScreenTextView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="This is the Main Screen"
        android:textColor="#000000"
        android:background="#666666"
        android:padding="5dp"
        android:textSize="20dp"/>
</LinearLayout>

<android.support.design.widget.FloatingActionButton
    android:id="@+id/fab"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="bottom|end"
    android:layout_margin="@dimen/fab_margin"
    android:src="@android:drawable/ic_dialog_email" />

回答1:

Per the readme, you need to include the butterknife-compiler in order for the generated code to be produced automatically:

buildscript {
  repositories {
    mavenCentral()
   }
  dependencies {
    classpath 'com.neenbedankt.gradle.plugins:android-apt:1.8'
  }
}

apply plugin: 'com.neenbedankt.android-apt'

dependencies {
  compile 'com.jakewharton:butterknife:8.0.1'
  apt 'com.jakewharton:butterknife-compiler:8.0.1'
}

Without this there is no generated code to be loaded and thus none of the fields get set.

You can verify ButterKnife is working by calling ButterKnife.setDebug(true) and looking in Logcat.

回答2:

I used this library in Fragment and has NPE. My code was:

ButterKnife.bind(view);

But it was wrong. Library need to know two objects:
1) Target - with annotations @BindView
2) Source - with views

It will be right to write:

ButterKnife.bind(this, view);

When this - your fragment, and view - view of this fragment.

回答3:

App Level(build.gradle)

apply plugin: 'android-apt'
dependencies {
    compile fileTree(include: ['*.jar'], dir: 'libs')
    compile 'com.android.support:appcompat-v7:24.2.1'
    testCompile 'junit:junit:4.12'
    compile 'com.jakewharton:butterknife:8.4.0'
    apt 'com.jakewharton:butterknife-compiler:8.4.0'
}


Project Level(build.gradle)

buildscript {
    repositories {
        jcenter()
    }
    dependencies {

        classpath 'com.neenbedankt.gradle.plugins:android-apt:1.8'
        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

回答4:

for me the problem was that I was using

annotationProcessor 'com.jakewharton:butterknife-compiler:8.7.0'

instead of

 apt 'com.jakewharton:butterknife-compiler:8.7.0

回答5:

Config Butterknife on build.gradle file like this,

compile("com.jakewharton:butterknife:8.5.1")
annotationProcessor "com.jakewharton:butterknife-compiler:8.5.1"

It works for me.

回答6:

I had this issue too, just because I've added butterknife from Android Studio's Dependency management and not by copy-pasting gradle lines from Butterknife website. So I had to add compile 'com.jakewharton:butterknife:8.5.1' annotationProcessor 'com.jakewharton:butterknife-compiler:8.5.1' instead of just compile 'com.jakewharton:butterknife:8.5.1'

回答7:

If you use kotlin:

make sure to use this dependency in module app:

dependencies {
   implementation 'com.jakewharton:butterknife:10.0.0'
   kapt 'com.jakewharton:butterknife-compiler:10.0.0'
}

回答8:

From JakeWharton

Yes that plugin is no longer needed. You're already using annotationProcessor for the 'butterknife-compiler' artifact which is built-in to the Android Gradle plugin.

Then the solution is delete apt classpath 'com.neenbedankt.gradle.plugins:android-apt:1.8'

回答9:

I have just faced this problem, after updating my project to Gradle version 3.0.1. I was able to fix it by just including in Gradle app file the line:

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

The final result was:

    dependencies {
        compile fileTree(include: ['*.jar'], dir: 'libs')
        androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
            exclude group: 'com.android.support', module: 'support-annotations'
        })

        ...

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

I hope this helps somebody, although this question being old.

回答10:

Add annotationProcessor 'com.jakewharton:butterknife-compiler:8.6.0' In your gradle file it worked for me

来源：https://stackoverflow.com/questions/37013619/butterknife-8-0-1-not-working

标签

android

nullpointerexception

butterknife