Android Kotlin Fundamentals: Create a fragment✍

이 포스팅은 아래 구글 코드랩을 개인 학습용으로 정리한 글입니다.

• Android Kotlin Fundamentals: Create a fragment
• Android Kotlin Fundamentals:03.2 Define navigation paths

🏁Android Kotlin Fundamentals: Create a fragment

1. Welcome

2. App overview

3. Task: Explore the starter app project

4. Task: Add a fragment

Step 1: Add a Fragment class

• 새 Fragment 생성하기
  • Fragment name: TitleFragment
  • Fragment layout name: placeholder_layout

TitleFragment.kt

class TitleFragment : Fragment() {

    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        val binding = DataBindingUtil.inflate<FragmentTitleBinding>(inflater, R.layout.fragment_title, container, false)
        return binding.root
    }

}

• DataBindingUtil.inflate의 매개변수
  • inflater: LayoutInflater used to inflate the binding layout
  • The XML layout resource of the layout to inflate
  • container for the parent ViewGroup (optional)
  • false: for the attachToParent value

Step 2: Add the new fragment to the main layout file

activity_main.xml

<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical">
        
            <fragment
                android:id="@+id/titleFragment"
                android:name="com.example.android.navigation.TitleFragment"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                />
        </LinearLayout>

</layout>

5. Solution code

6. Summary

• Use the $<$fragment$>$ tag to define the layout for the Fragment in the XML layout file.

• Inflate the layout for a Fragment in onCreateView().

🏁Android Kotlin Fundamentals:03.2 Define navigation paths

1. Welcome

2. App overview

3. Task: Add navigation components to the project

Step 1: Add navigation dependencies

build.gradle(Project)

buildscript {
    ext {
        ...
        navigationVersion = '2.5.3'
    }
    ...
}

build.gradle(Module:app)

dependencies{
	...
    implementation "androidx.navigation:navigation-fragment-ktx:$navigationVersion"
    implementation "androidx.navigation:navigation-ui-ktx:$navigationVersion"
    ...
}

Step 2: Add a navigation graph to the project

• res 폴더 우클릭>New>New Resource File

  • Resource Type: Navigation
  • File name: navigation

• navigation.xml>Design>Navigation Editor

  • No NavHostFragments found message

4. Task: Create the NavHostFragment

activity_main.xml

• modify activity_main.xml to replace the TitleFragment with the NavHostFragment

<fragment
            android:id="@+id/myNavHostFragment"
            android:name="androidx.navigation.fragment.NavHostFragment"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:defaultNavHost="true"
            app:navGraph="@navigation/navigation" />

5. Task: Add fragments to the navigation graph

Step 1: Add two fragments to the navigation graph and connect them with an action

➕ navigation.xml>Naviagation Editor>New Destination Button을 눌렀을 때 목록에 fragment_title이 나타나지 않는 현상 발생

해결 방법: 기존에 있던 TitleFragment.kt과 fragment_title.xml 삭제
-> Create New Destination > TitleFragment.kt과 fragment_title.xml 새로 생성

Step 2: Add a click handler to the Play button

✍...

📌참고자료

• [Android] Cannot fit requested classes in a single dex file 해결 방법 및 원인 분석

minSdkVersion 21 이상인 경우:
build.gradle(app) 파일에서 multiDexEnable을 true로 설정

android {
    defaultConfig {
    	...
        multiDexEnabled true 
    }
    ...
}