Using Butter Knife in Android

Butter Knife  is View "injection" library for Android which uses annotation processing to generate the code for you.

we should follow these steps

• Eliminate findViewById calls by using @InjectView on fields.
• Group multiple views in a list using @InjectViews. 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.

for an example create a project and have a layout as follows

example.xml

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="vertical" >

    <EditText

        android:id="@+id/editText1"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:hint="Insert Username" />

    <EditText

        android:id="@+id/editText2"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:hint="Insert Password"

        android:inputType="textPassword" />

    <Button

        android:id="@+id/button1"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:text="Login" />

</LinearLayout>

correspondingly write the Activity code as follows

SimpleActivity.java 

import static android.widget.Toast.LENGTH_SHORT;

import android.app.Activity;

import android.os.Bundle;

import android.widget.Button;

import android.widget.EditText;

import android.widget.Toast;

import butterknife.ButterKnife;

import butterknife.InjectView;

import butterknife.OnClick;

public class SimpleActivity extends Activity {

       @InjectView(R.id.editText1)

EditText username;

@InjectView(R.id.editText2)

EditText password;

@InjectView(R.id.button1)

Button login;

@OnClick(R.id.button1) void sayLogin() {

Toast.makeText(this, "Hello!"+" yours username is "+username.getText().toString()+" & Yours password is "+password.getText().toString(), LENGTH_SHORT).show();

}

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.example);

ButterKnife.inject(this);

}

}

beside this write application class as follows

import android.app.Application;

import butterknife.ButterKnife;

public class SimpleApp extends Application {

@Override

public void onCreate() {

super.onCreate();

ButterKnife.setDebug(BuildConfig.DEBUG);

}

}

and include it at manifest as 

 <application

        android:name="com.packagenamee.SimpleApp"  .....

finally run the code and see a login screen, Happy coding

download the butter knife jar from 

http://jakewharton.github.io/butterknife/

on having problems and issues follow

https://github.com/JakeWharton/butterknife/issues/12