How to use ButterKnife In Android?

This example demonstrates how do I ButterKnife in android.

Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.

Step 2 − Add the following code to res/layout/activity_main.xml.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="https://schemas.android.com/apk/res/android"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   android:gravity="center_horizontal"
   android:orientation="vertical">
   <TextView
      android:id="@+id/textView"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="..........."
      android:textSize="16sp"
      android:textStyle="bold"
      android:textAllCaps="true" />
   <TextView
      android:id="@+id/textView2"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="..........."
      android:textSize="16sp"
      android:textStyle="bold"
      android:textAllCaps="true" />
   <TextView
      android:id="@+id/textView3"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="..........."
      android:textSize="16sp"
      android:textStyle="bold"
      android:textAllCaps="true" />
   <Button
      android:id="@+id/btnLoadText"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:textSize="16sp"
      android:textStyle="bold"
      android:text="Load Text" />
</LinearLayout>

Step 3 – Open build.gradle(Module App) and add the following dependency

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

Step 4 − Add the following code to src/MainActivity.java

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import butterknife.BindView;
import butterknife.ButterKnife;
public class MainActivity extends AppCompatActivity {
   @BindView(R.id.textView)
   TextView textView;
   @BindView(R.id.textView2)
   TextView textView2;
   @BindView(R.id.textView3)
   TextView textView3;
   @BindView(R.id.btnLoadText)
   Button button;
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      ButterKnife.bind(this);
      textView = findViewById(R.id.textView);
      textView2 = findViewById(R.id.textView2);
      textView3 = findViewById(R.id.textView3);
      button = findViewById(R.id.btnLoadText);
      button.setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View v) {
            textView.setText("Hi, How are you?");
            textView2.setText("Have a nice day!");
            textView3.setText("You are so good.");
         }
      });
   }
}

Step 5 - Add the following code to androidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="https://schemas.android.com/apk/res/android"
   package="app.com.sample">
   <application
      android:allowBackup="true"
      android:icon="@mipmap/ic_launcher"
      android:label="@string/app_name"
      android:roundIcon="@mipmap/ic_launcher_round"
      android:supportsRtl="true"
      android:theme="@style/AppTheme">
      <activity android:name=".MainActivity">
         <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
         </intent-filter>
      </activity>
   </application>
</manifest>

Let's try to run your application. I assume you have connected your actual Android Mobile device with your computer. To run the app from android studio, open one of your project's activity files and click Run icon from the toolbar. Select your mobile device as an option and then check your mobile device which will display your default screen –