Android/Kotlin

[Kotlin]  Activity에서 Fragment로 데이터 전달

혀가 길지 않은 개발자 2020. 10. 24. 17:15

1. onAttach()에서 Context 파라미터를 이용하여 Activity 객체를 생성하는 방법

2. Bundle 객체를 생성해서 Fragment의 전달인자로 보내는 방법

3. ViewModel을 공유하는 방법

1. onAttach()에서 Context 파라미터로 Activity 객체 생성하여 전달받는 방법

 

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    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:orientation="vertical"
    android:gravity="center"
    tools:context=".MainActivity">

    <FrameLayout
        android:id="@+id/frameLayout"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"/>

    <Button
        android:id="@+id/btnChange"
        android:layout_width="match_parent"
        android:layout_height="70dp"
        android:textAllCaps="false"
        android:text="Change Fragment"
        android:textSize="22dp"/>

</LinearLayout>

 

 

 

 

fragment_red.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#FFBBBB">

    <TextView
        android:id="@+id/tvName"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="30dp"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        tools:text="이름"/>

</androidx.constraintlayout.widget.ConstraintLayout>

fragment_red.xml

 

 

 

 

fragment_green.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#BBFFBB">

    <TextView
        android:id="@+id/tvName"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="30dp"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        tools:text="이름"/>

</androidx.constraintlayout.widget.ConstraintLayout>

fragment_green.xml

 

 

 

FragmentGreen.kt

package com.jwsoft.kotlinproject

import android.content.Context
import android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import androidx.fragment.app.Fragment

class FragmentGreen : Fragment() {

    private lateinit var name: String

    override fun onAttach(context: Context) {
        super.onAttach(context)
        name = (context as MainActivity).getName()
    }

    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        return inflater.inflate(R.layout.fragment_green, container, false)
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        val tvName = view.findViewById<TextView>(R.id.tvName)
        tvName.text = name
    }

}

 

 

 

 

FragmentRed.kt

package com.jwsoft.kotlinproject

import android.content.Context
import android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import androidx.fragment.app.Fragment

class FragmentRed : Fragment() {

    private lateinit var name: String

    override fun onAttach(context: Context) {
        super.onAttach(context)
        name = (activity as MainActivity).getName()
    }

    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        return inflater.inflate(R.layout.fragment_red, container, false)
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        val tvName = view.findViewById<TextView>(R.id.tvName)
        tvName.text = name
    }

}

 

 

 

 

MainActivity.kt

package com.jwsoft.kotlinproject

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import androidx.fragment.app.FragmentTransaction
import kotlinx.android.synthetic.main.activity_main.*

class MainActivity : AppCompatActivity() {

    private val fragmentManager = supportFragmentManager
    private lateinit var transaction: FragmentTransaction
    private var isRed = false
    private var name = ""

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        transaction = fragmentManager.beginTransaction()
        transaction.add(R.id.frameLayout, FragmentRed())
        transaction.add(R.id.frameLayout, FragmentGreen())
        transaction.commit()

        btnChange.setOnClickListener {

            transaction = fragmentManager.beginTransaction()

            if (isRed) {
                transaction.replace(R.id.frameLayout, FragmentGreen())
                name = "James Kim Green"
            } else {
                transaction.replace(R.id.frameLayout, FragmentRed())
                name = "James Kim Red"
            }

            isRed = !isRed
            transaction.commit()

        }

    }

    fun getName(): String {
        return name
    }

}

실행 결과

 

 

 

 

 

2. Bundle 객체를 생성해서 Fragment의 전달인자로 보내는 방법

 

fragment_red.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#FFBBBB">

    <TextView
        android:id="@+id/tvName"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="30dp"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        tools:text="이름"/>

</androidx.constraintlayout.widget.ConstraintLayout>

fragment_red.xml

 

 

 

 

fragment_green.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#BBFFBB">

    <TextView
        android:id="@+id/tvName"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="30dp"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        tools:text="이름"/>

</androidx.constraintlayout.widget.ConstraintLayout>

fragment_green.xml

 

 

 

 

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    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:orientation="vertical"
    android:gravity="center"
    tools:context=".MainActivity">

    <FrameLayout
        android:id="@+id/frameLayout"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"/>

    <Button
        android:id="@+id/btnChange"
        android:layout_width="match_parent"
        android:layout_height="70dp"
        android:textAllCaps="false"
        android:text="Change Fragment"
        android:textSize="22dp"/>

</LinearLayout>

activity_main.xml

 

 

 

 

FragmentRed.kt

package com.jwsoft.kotlinproject

import android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import androidx.fragment.app.Fragment

class FragmentRed : Fragment() {

    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        return inflater.inflate(R.layout.fragment_red, container, false)
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)

        val tvName = view.findViewById<TextView>(R.id.tvName)
        val bundle = arguments
        tvName.text = bundle?.getString("name")
    }

}

 

 

 

 

 

FragmentGreen.kt

package com.jwsoft.kotlinproject

import android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import androidx.fragment.app.Fragment

class FragmentGreen : Fragment() {

    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        return inflater.inflate(R.layout.fragment_green, container, false)
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)

        val tvName = view.findViewById<TextView>(R.id.tvName)
        val bundle = arguments
        tvName.text = bundle?.getString("name")
    }

}

 

 

 

 

 

MainActivity.kt

package com.jwsoft.kotlinproject

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import androidx.fragment.app.FragmentTransaction
import kotlinx.android.synthetic.main.activity_main.*

class MainActivity : AppCompatActivity() {

    private val fragmentManager = supportFragmentManager
    private lateinit var transaction: FragmentTransaction
    private var isRed = false

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        transaction = fragmentManager.beginTransaction()
        transaction.add(R.id.frameLayout, FragmentRed())
        transaction.add(R.id.frameLayout, FragmentGreen())
        transaction.commit()

        btnChange.setOnClickListener {

            transaction = fragmentManager.beginTransaction()

            val bundle = Bundle()
            if (isRed) {
                bundle.putString("name", "James Kim Green")
                transaction.replace(R.id.frameLayout, FragmentGreen().apply { arguments = bundle })
            } else {
                bundle.putString("name", "James Kim Red")
                transaction.replace(R.id.frameLayout, FragmentRed().apply { arguments = bundle })
            }

            isRed = !isRed
            transaction.commit()

        }

    }

}

실행 결과

 

 

 

 

 

 

3. ViewModel을 공유하는 방법

 

fragment_red.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#FFBBBB">

    <TextView
        android:id="@+id/tvName"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="30dp"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        tools:text="이름"/>

</androidx.constraintlayout.widget.ConstraintLayout>

fragment_red.xml

 

 

 

 

fragment_green.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#BBFFBB">

    <TextView
        android:id="@+id/tvName"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="30dp"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        tools:text="이름"/>

</androidx.constraintlayout.widget.ConstraintLayout>

fragment_green.xml

 

 

 

 

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    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:orientation="vertical"
    android:gravity="center"
    tools:context=".MainActivity">

    <FrameLayout
        android:id="@+id/frameLayout"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"/>

    <Button
        android:id="@+id/btnChange"
        android:layout_width="match_parent"
        android:layout_height="70dp"
        android:textAllCaps="false"
        android:text="Change Fragment"
        android:textSize="22dp"/>

</LinearLayout>

activity_main.xml

 

 

 

 

ActivityViewModel.kt

package com.jwsoft.kotlinproject

import androidx.lifecycle.MutableLiveData
import androidx.lifecycle.ViewModel

class ActivityViewModel : ViewModel() {

    var name: MutableLiveData<String> = MutableLiveData()

}

 

 

 

 

 

FragmentRed.kt

package com.jwsoft.kotlinproject

import android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import androidx.fragment.app.Fragment
import androidx.lifecycle.Observer
import androidx.lifecycle.ViewModelProvider

class FragmentRed : Fragment() {

    private lateinit var viewModel: ActivityViewModel
    private lateinit var tvName: TextView

    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        viewModel = ViewModelProvider(requireActivity(), ViewModelProvider.NewInstanceFactory())
            .get(ActivityViewModel::class.java)

        return inflater.inflate(R.layout.fragment_red, container, false)
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        tvName = view.findViewById(R.id.tvName)
        viewModel.name.observe(this, Observer {
            tvName.text = it
        })
    }

}

 

 

 

 

 

 

FragmentGreen.kt

package com.jwsoft.kotlinproject

import android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import androidx.fragment.app.Fragment
import androidx.lifecycle.Observer
import androidx.lifecycle.ViewModelProvider

class FragmentGreen : Fragment() {

    private lateinit var viewModel: ActivityViewModel
    private lateinit var tvName: TextView

    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        viewModel = ViewModelProvider(requireActivity(), ViewModelProvider.NewInstanceFactory())
            .get(ActivityViewModel::class.java)

        return inflater.inflate(R.layout.fragment_green, container, false)
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        tvName = view.findViewById(R.id.tvName)
        viewModel.name.observe(this, Observer {
            tvName.text = it
        })
    }

}

 

 

 

 

 

MainActivity.kt

package com.jwsoft.kotlinproject

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import androidx.fragment.app.FragmentTransaction
import androidx.lifecycle.ViewModelProvider
import kotlinx.android.synthetic.main.activity_main.*

class MainActivity : AppCompatActivity() {

    private lateinit var viewModel: ActivityViewModel
    private val fragmentManager = supportFragmentManager
    private lateinit var transaction: FragmentTransaction
    private var isRed = false

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        viewModel = ViewModelProvider(this, ViewModelProvider.NewInstanceFactory())
            .get(ActivityViewModel::class.java)

        transaction = fragmentManager.beginTransaction()
        transaction.add(R.id.frameLayout, FragmentRed())
        transaction.add(R.id.frameLayout, FragmentGreen())
        transaction.commit()

        btnChange.setOnClickListener {

            transaction = fragmentManager.beginTransaction()

            if (isRed) {
                viewModel.name.value = "James Kim Green"
                transaction.replace(R.id.frameLayout, FragmentGreen())
            } else {
                viewModel.name.value = "James Kim Red"
                transaction.replace(R.id.frameLayout, FragmentRed())
            }

            isRed = !isRed
            transaction.commit()

        }

    }

}

실행 결과

 

 

 

 

 

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