butterknife README

The project's README from github.com/JakeWharton/butterknife. As one markdown file: README.md.

Butter Knife

Attention: This tool is now deprecated. Please switch to view binding. Existing versions will continue to work, obviously, but only critical bug fixes for integration with AGP will be considered. Feature development and general bug fixes have stopped.

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

android {
  ...
  // Butterknife requires Java 8.
  compileOptions {
    sourceCompatibility JavaVersion.VERSION_1_8
    targetCompatibility JavaVersion.VERSION_1_8
  }
}

dependencies {
  implementation 'com.jakewharton:butterknife:10.2.3'
  annotationProcessor 'com.jakewharton:butterknife-compiler:10.2.3'
}

If you are using Kotlin, replace annotationProcessor with kapt.

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 {
  repositories {
    mavenCentral()
    google()
  }
  dependencies {
    classpath 'com.jakewharton:butterknife-gradle-plugin:10.2.3'
  }
}

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.

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What is this?

Butter Knife is an Android library that binds views and callbacks to fields and methods, using annotation processing to generate the boilerplate code for you.

How does it work in code?

You annotate fields and methods instead of writing lookup code: @BindView removes findViewById calls, @OnClick replaces anonymous listener classes, and resource annotations remove resource lookups.

How do I add it to an Android project?

Add Butter Knife as a Gradle dependency wired through annotationProcessor; in Kotlin projects use kapt instead.

Is it still maintained, or should new projects avoid it?

The project is deprecated: feature development and general bug fixes have stopped, and only critical fixes for AGP integration are considered. The README says to switch to view binding instead.

What can I do beyond binding single views?

You can group multiple views in a list or array and operate on all of them at once with actions, setters, or properties.

Does it work inside Android library modules?

Yes — add the Butter Knife plugin to your buildscript, apply it in the module, and use R2 instead of R inside all Butter Knife annotations.

Why is it called Butter Knife?

The README jokes that a butter knife is like a Dagger, only infinitely less sharp — a playful nod to the Dagger dependency injection library.

What are similar projects?

AndroidSwipeLayout, androidannotations, anko, EventBus, MVPArms, greenDAO, platform_frameworks_base, material-components-android

Which topics is it in?

java-library, legacy, kotlin-android, android-development, jvm, android-library, boilerplate, build-tool, code-generation, mobile-development, deprecated, java

Creator: JakeWharton
Size: 3.8 MB
Stars: 25.3K
Updated: CommitSep 04
Age: 13y
Commits · 90 Days