hello hello
I think I implemented it as needed… why Am I getting this error?
Expecting Member Declaration for CrimeListFragment.Callbacks despite it is working fine after onCreate…
package com.bignerdranch.android.criminalintent
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import java.util.*
class MainActivity : AppCompatActivity() {
/*
Implementing callbacks inside the hosting activity to change the fragment once needed.
*/
CrimeListFragment.Callbacks {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
/*
to add a fragment into activity in code, we call FragmentManager.
we instantiate the fragment with the fragment manager. and set the condition to show it
in case it is null, call fragment manager to start transaction and add the fragment container
as the view and its code file CrimeFragment() in action, then commit them to OS.
transactions are used to add, remove, attach, detach or replace a fragment
*/
val currentFragment = //<-- When we need to retrieve the CrimeFragment from
// the fragment manager you asked for it by container view ID
supportFragmentManager.findFragmentById(R.id.fragment_container)
if (currentFragment == null) {
val fragment = CrimeListFragment.newInstance()
supportFragmentManager
.beginTransaction()
.add(R.id.fragment_container, fragment)
.commit()
}
}
override fun onCrimeSelected(crimeid: UUID) {
supportFragmentManager
.beginTransaction()
.replace(R.id.fragment_container, CrimeFragment())
.commit()
}
}
}