[ButterKnife] Sum and Diff Simple Android App

Hello Guys!

 In Android development, One of the famous open source library  is Butterknife. What is ButterKnife? A Library that binds your Android views which uses annotation process. built by Jake Wharton.
- Very light weight.
- Eliminates long codes in finding your Android views.
- It uses annotation such as @Bind, @OnClick and more.
- Clean code and organize.
- Binds String resources.

Personally I always includes this library in most of my projects , I highly recommend you guys to use this, it will improve your speed in production.

 you can add this library using Gradle system of Android studio

dependencies {
   compile 'com.jakewharton:butterknife:7.0.1'
}

After syncing your Gradle, you can now use Butterknife in your project.

Here's My Example Android App that can get the Sum or Diff of two numbers.

1.MainActivity.java

package com.example.uge.butterknifesample;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;;
import android.view.inputmethod.InputMethodManager;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import butterknife.Bind;
import butterknife.ButterKnife;
import butterknife.OnClick;

public class MainActivity extends AppCompatActivity {

    @Bind(R.id.firstNum)
    EditText firstNum;

    @Bind(R.id.secondNum)
    EditText secondNum;


    @Bind(R.id.answerText)
    TextView answerTxt;

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

    }

    @OnClick(R.id.sumBtn)
    void getTheSumOfTwoNumbers(){
        if(validateEditText()){
            int fValue = Integer.parseInt(firstNum.getText().toString());
            int sValue = Integer.parseInt(secondNum.getText().toString());
            int sumValue = fValue + sValue;
            answerTxt.setText("Sum: " + sumValue);
        }else{
            Toast.makeText(this, "Please Input the Values in the EditText(s)", Toast.LENGTH_SHORT).show();
        }
        hideKeyboard();
    }

    @OnClick(R.id.diffBtn)
    void getTheDiffOfTwoNumbers(){
        if(validateEditText()){
            int fValue = Integer.parseInt(firstNum.getText().toString());
            int sValue = Integer.parseInt(secondNum.getText().toString());
            int diffValue = fValue - sValue;
            answerTxt.setText("Diff: " + diffValue);
        }else{
            Toast.makeText(this, "Please Input the Values in the EditText(s)", Toast.LENGTH_SHORT).show();
        }
        hideKeyboard();
    }

    public Boolean validateEditText(){
        //The Two EditText must have a value
        if(firstNum.getText().toString().length() > 0 && secondNum.getText().toString().length() > 0){
            return true;
        }else{
            return false;
        }
    }

    public void hideKeyboard(){
        InputMethodManager imm = (InputMethodManager) getSystemService(INPUT_METHOD_SERVICE);
        if(imm.isAcceptingText()) { // verify if the soft keyboard is open
            imm.hideSoftInputFromWindow(getCurrentFocus().getWindowToken(), 0);
        }
    }

}

2. Layout (activity_main.xml)

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_margin="15dp"
    tools:context="com.example.uge.butterknifesample.MainActivity">

    <EditText
        android:id="@+id/firstNum"
        android:layout_width="match_parent"
        android:layout_height="45dp"
        android:inputType="number"
        android:hint="First Number" />

    <EditText
        android:id="@+id/secondNum"
        android:layout_width="match_parent"
        android:layout_height="45dp"
        android:hint="Second Number"
        android:inputType="number"
        android:layout_below="@+id/firstNum" />

    <Button
        android:id="@+id/sumBtn"
        android:layout_width="match_parent"
        android:layout_height="45dp"
        android:text="Sum"
        android:layout_below="@+id/secondNum"
        android:layout_margin="5dp"/>
    <TextView
        android:id="@+id/orText"
        android:layout_below="@+id/sumBtn"
        android:gravity="center"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="OR"
        android:layout_margin="5dp"/>
    <Button
        android:id="@+id/diffBtn"
        android:layout_width="match_parent"
        android:layout_height="45dp"
        android:text="Difference"
        android:layout_below="@+id/orText"
        android:layout_margin="5dp"/>


    <TextView
        android:id="@+id/answerText"
        android:textSize="20sp"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"/>

</RelativeLayout>

Here's the OUTPUT:

 


You can download the sources code here: ButterknifeSample


for automation of binding views in Butterknife you can use Butterknife zelezny