How to add fragment in android application?

Question

Android

trying to add snippet

MainActivity

Activity

package com.example.fragment
import android.content.Intent
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.view.View

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
    }
    fun onShowDetails(view: View) {
        var intent = Intent([email protected], DetailActivity::class.java)
        startActivity(intent)
    }
}

Разметка

<?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"
    tools:context=".MainActivity">
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        android:padding="16dp"
        >

        <Button
            android:id="@+id/button"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:onClick="onShowDetails"
            android:text="@string/onShowDetail"
            tools:layout_editor_absoluteX="162dp"
            tools:layout_editor_absoluteY="274dp" />
    </LinearLayout>
</androidx.constraintlayout.widget.ConstraintLayout>

DetailActivity

Activity

package com.example.fragment
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import androidx.fragment.app.Fragment
import androidx.fragment.app.FragmentManager
import androidx.fragment.app.FragmentTransaction

class DetailActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_detail)
        var fragManger:FragmentManager = supportFragmentManager
        var fragTrans:FragmentTransaction = fragManger.beginTransaction()

        var myFrag:Fragment = WorkOutDetailFragment()
        fragTrans.add(R.id.framenttestid, myFrag)
        fragTrans.commit()
    }
}

Разметка

<?xml version="1.0" encoding="utf-8"?>

    <LinearLayout
        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"
        tools:context=".DetailActivity"
        android:orientation="vertical"
    >
    <LinearLayout
        android:id="@+id/framenttestid"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical" />
    </LinearLayout>

Fragment

Фрагмент

package com.example.fragment

import android.content.Context
import android.net.Uri
import android.os.Bundle
import androidx.fragment.app.Fragment
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup

// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private const val ARG_PARAM1 = "param1"
private const val ARG_PARAM2 = "param2"

class WorkOutDetailFragment : Fragment() {
    // TODO: Rename and change types of parameters
    private var param1: String? = null
    private var param2: String? = null
    private var listener: OnFragmentInteractionListener? = null

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        arguments?.let {
            param1 = it.getString(ARG_PARAM1)
            param2 = it.getString(ARG_PARAM2)
        }
    }

    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_work_out_detail, container, false)
    }

    // TODO: Rename method, update argument and hook method into UI event
    fun onButtonPressed(uri: Uri) {
        listener?.onFragmentInteraction(uri)
    }

    override fun onAttach(context: Context) {
        super.onAttach(context)
        if (context is OnFragmentInteractionListener) {
            listener = context
        } else {
            throw RuntimeException(context.toString() + " must implement OnFragmentInteractionListener")
        }
    }

    override fun onDetach() {
        super.onDetach()
        listener = null
    }


    interface OnFragmentInteractionListener {
        // TODO: Update argument type and name
        fun onFragmentInteraction(uri: Uri)
    }

    companion object {

        @JvmStatic
        fun newInstance(param1: String, param2: String) =
            WorkOutDetailFragment().apply {
                arguments = Bundle().apply {
                    putString(ARG_PARAM1, param1)
                    putString(ARG_PARAM2, param2)
                }
            }
    }
}

Разметка

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout 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"
    tools:context=".WorkOutDetailFragment">

    <!-- TODO: Update blank fragment layout -->
    <LinearLayout
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="match_parent">
        <TextView
            android:id="@+id/textTitle"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:text="@string/workout_title"
            android:textAppearance="@style/TextAppearance.AppCompat.Large"/>
        <TextView
            android:id="@+id/textDescription"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:text="@string/workout_description" />
    </LinearLayout>
</FrameLayout>

the error occurs when trying to push the WorkOutDetailFragment fragment into the DetailActivity markup

error

2020-05-23 11:21:59.867 1981-1981/com.example.fragment E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.fragment, PID: 1981
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.fragment/com.example.fragment.DetailActivity}: java.lang.RuntimeException: [email protected] must implement OnFragmentInteractionListener
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2665)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2726)
        at android.app.ActivityThread.-wrap12(ActivityThread.java)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1477)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:154)
        at android.app.ActivityThread.main(ActivityThread.java:6119)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
     Caused by: java.lang.RuntimeException: [email protected] must implement OnFragmentInteractionListener
        at com.example.fragment.WorkOutDetailFragment.onAttach(WorkOutDetailFragment.kt:48)
        at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManager.java:1404)
        at androidx.fragment.app.FragmentTransition.addToFirstInLastOut(FragmentTransition.java:1195)
        at androidx.fragment.app.FragmentTransition.calculateFragments(FragmentTransition.java:1078)
        at androidx.fragment.app.FragmentTransition.startTransitions(FragmentTransition.java:117)
        at androidx.fragment.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2408)
        at androidx.fragment.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManager.java:2366)
        at androidx.fragment.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2273)
        at androidx.fragment.app.FragmentManagerImpl.dispatchStateChange(FragmentManager.java:3273)
        at androidx.fragment.app.FragmentManagerImpl.dispatchActivityCreated(FragmentManager.java:3229)
        at androidx.fragment.app.FragmentController.dispatchActivityCreated(FragmentController.java:201)
        at androidx.fragment.app.FragmentActivity.onStart(FragmentActivity.java:620)
        at androidx.appcompat.app.AppCompatActivity.onStart(AppCompatActivity.java:178)
        at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1248)
        at android.app.Activity.performStart(Activity.java:6696)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2628)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2726) 
        at android.app.ActivityThread.-wrap12(ActivityThread.java) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1477) 
        at android.os.Handler.dispatchMessage(Handler.java:102) 
        at android.os.Looper.loop(Looper.java:154) 
        at android.app.ActivityThread.main(ActivityThread.java:6119) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776) 

Answer 1

Well, it tells you [email protected] must implement OnFragmentInteractionListener