Cannot remove Fragment in Android-CodePudding

I have two fragments, named them "Red" and "Blue" and three buttons. The first one adds "Red" fragment and changes the background to red color, the second one adds "Blue" fragment and changes the background to blue color and the third one has to remove the current fragment and change the color to the previous fragment's color.

The problem is that when I click the remove button I see a toast that the fragment is removed but the layout doesn't change to the color of the previous fragment.

var fragment1 = FirstFragment()
var fragment2 = SecondFragment()
lateinit var binding: ActivityMainBinding
var counter: Int = 0

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    binding = ActivityMainBinding.inflate(layoutInflater)
    setContentView(binding.root)


    binding.redBtn.setOnClickListener {
        supportFragmentManager
            .beginTransaction()
            .add(R.id.placeHolder, fragment1)
            .addToBackStack("Red")
            .commit()
        counter  
        binding.count.text = "$counter"
    }

    binding.blueBtn.setOnClickListener {
        supportFragmentManager
            .beginTransaction()
            .replace(R.id.placeHolder, fragment2)
            .addToBackStack("Blue")
            .commit()
        counter  
        binding.count.text = "$counter"
    }

    binding.removeBtn.setOnClickListener {

        val fragmentInstance = supportFragmentManager.findFragmentById(R.id.placeHolder)

        if(fragmentInstance is FirstFragment){
            supportFragmentManager.beginTransaction()
                .remove(FirstFragment())
                .commit()
            Toast.makeText(this, "Removed Red Fragment", Toast.LENGTH_SHORT).show()
        } else {
            supportFragmentManager.beginTransaction()
                .remove(SecondFragment())
                .commit()
            Toast.makeText(this, "Removed Blue Fragment", Toast.LENGTH_SHORT).show()
        }

        counter--
        binding.count.text = "$counter"
    }


}

}

CodePudding user response：

It will not remove directly

make sure create object of First and Second Fragment

Then when you add or remove fragment from fragment manager use the same fragment object

Like you created fragment1 and fragment2

CodePudding user response：

Hello i think you have just to pass the framgents objects that aleady createed to be removed like this:


    binding.removeBtn.setOnClickListener {

        val fragmentInstance = supportFragmentManager.findFragmentById(R.id.placeHolder)

        if(fragmentInstance is FirstFragment){
            supportFragmentManager.beginTransaction()
                .remove(fragment1)
                .commit()
            Toast.makeText(this, "Removed Red Fragment", Toast.LENGTH_SHORT).show()
        } else {
            supportFragmentManager.beginTransaction()
                .remove(fragment2)
                .commit()
            Toast.makeText(this, "Removed Blue Fragment", Toast.LENGTH_SHORT).show()
        }

        counter--
        binding.count.text = "$counter"
    }

your problem is every click on remove btn will create new instance of fragment not the object already created