Naming
Last modified on Wed 09 Feb 2022

Good naming makes it easier to read and understand code.

Consider the following two versions of functionally equivalent code.

val list1 = arrayListOf<String>()
list2.forEach { x ->
  if(x.length <= 4) {
    list1.add(x)
  }
}
return list1
val shortFileNames = arrayListOf<String>()
fileNames.forEach { name ->
  if (name.length <= FILE_NAME_LENGTH_LIMIT) {
    shortFileNames.add(name)
  }
}
return shortFileNames

Which one is more understandable?

To make your code understandable, you need to reveal your intent and avoid disinformation.

Methods which return boolean values should sound like questions.

if (isFileTooLarge(image))

is more readable than

if (checkFileSize(image))

Naming conventions

Examples of good naming

class WelcomeActivity : BaseActivity, WelcomeView {

    @InjectView(R.id.viewExchangeQuote)
    protected var exchangeQuoteView: ExchangeQuoteView? = null

    @InjectView(R.id.textSeeDetails)
    protected var seeDetailsText: TextView? = null

    @OnClick(R.id.textSeeDetails)
    protected fun onSeeDetailsClicked() {
        presenter.onDetailsRequested()
    }

    @OnClick(R.id.loginButton)
    protected fun onLoginButtonClicked() {
        presenter.onLoginButtonClicked()
    }

    @OnClick(R.id.registerButton)
    protected fun onRegisterButtonClicked() {
        presenter.onRegisterButtonClicked()
    }

    override fun showCurrencies(currencies: List<Currency>) {
        exchangeQuoteView.showCurrencies(currencies)
    }

    override fun showSellingAmount(sellingAmount: String) {
        exchangeQuoteView.showSellingAmount(sellingAmount)
    }

    override fun showBuyingAmount(buyingAmount: String) {
        exchangeQuoteView.showBuyingAmount(buyingAmount)
    }

    override fun navigateToLogin() {
        val intent = Intent(this, LoginActivity::class.java)
        startActivityForResult(intent, REQUEST_CODE_LOGIN)
    }

    override fun navigateToRegister() {
        val intent: Intent = RegistrationActivity.buildIntent(this)
        startActivityForResult(intent, REQUEST_CODE_REGISTER)
    }

    companion object {
        const val REQUEST_CODE_LOGIN = 147
        const val REQUEST_CODE_REGISTER = 148
        const val EXTRA_ACTION = "EXTRA_ACTION"
    }
}
<ScrollView 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">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">

        <co.infinum.currencyfair.custom.ExchangeQuoteView
            android:id="@+id/viewExchangeQuote"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:visibility="invisible"
            tools:visibility="visible"/>

        <com.ivankocijan.magicviews.views.MagicTextView
            android:id="@+id/textSeeDetails"
            style="@style/TextButton"
            android:padding="8dp"
            android:textAllCaps="false"
            tools:text="@string/see_how_you_save"
            android:visibility="invisible"
            tools:visibility="visible"/>

        <Space
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="1"/>

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal">

            <com.ivankocijan.magicviews.views.MagicButton
                android:id="@+id/registerButton"
                style="@style/AppTheme.Button"
                android:layout_width="0dp"
                android:layout_weight="0.5"
                android:layout_marginRight="8dp"
                android:text="@string/register"/>

            <Space android:layout_width="16dp"
                android:visibility="gone"
                android:layout_height="1dp"/>

            <com.ivankocijan.magicviews.views.MagicButton
                android:id="@+id/loginButton"
                style="@style/AppTheme.Button"
                android:layout_width="0dp"
                android:layout_weight="0.5"
                android:text="@string/login"/>

        </LinearLayout>
    </LinearLayout>
</ScrollView>