Butter Knife

Field and method binding for Android views which uses annotation processing to generate boilerplate code for you.

• Eliminate findViewById calls by using @BindView on fields.
• Group multiple views in a list or array. Operate on all of them at once with actions, setters, or properties.
• Eliminate anonymous inner-classes for listeners by annotating methods with @OnClick and others.
• Eliminate resource lookups by using resource annotations on fields.

class ExampleActivity extends Activity {
  @BindView(R.id.user) EditText username;
  @BindView(R.id.pass) EditText password;

  @BindString(R.string.login_error) String loginErrorMessage;

  @OnClick(R.id.submit) void submit() {
    // TODO call server...
  }

  @Override public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.simple_activity);
    ButterKnife.bind(this);
    // TODO Use fields...
  }
}

For documentation and additional information see the website.

Remember: A butter knife is like a dagger only infinitely less sharp.

Download

Configure your project-level build.gradle to include the 'android-apt' plugin:

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

Then, apply the 'android-apt' plugin in your module-level build.gradle and add the Butter Knife dependencies:

apply plugin: 'android-apt'

android {
  ...
}

dependencies {
  compile 'com.jakewharton:butterknife:8.2.1'
  apt 'com.jakewharton:butterknife-compiler:8.2.1'
}

Note: If you are using the new Jack compiler with version 2.2.0 or newer you do not need the 'android-apt' plugin and can instead replace apt with annotationProcessor when declaring the compiler dependency.

Snapshots of the development version are available in Sonatype's snapshots repository.

Library projects

To use Butter Knife in a library, add the plugin to your buildscript:

buildscript {
  dependencies {
    classpath 'com.jakewharton:butterknife-gradle-plugin:8.2.1'
  }
}

and then apply it in your module:

apply plugin: 'com.android.library'
apply plugin: 'com.jakewharton.butterknife'

Now make sure you use R2 instead of R inside all Butter Knife annotations.

class ExampleActivity extends Activity {
  @BindView(R2.id.user) EditText username;
  @BindView(R2.id.pass) EditText password;
...
}

License

Copyright 2013 Jake Wharton

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.