How to override onCancel in Dialog Fragment in Android in kotlin?

Question

I want to show a progress bar DialogFragment. It would be shown until either it is cancelled or dismissed. It can be cancelled if the user either presses back button or touches outside of the dialog, and is dismissed if the user doesn't cancel it before the completion of the task. So, I want to set listeners for both so I can respond according to the case. The dialog is being called from a Fragment.

According to this, I can't set listeners, instead I have to override the methods. My main problem is, I don't know how to do that in kotlin. I have written some of the code below but it is incomplete. Please correct the code where needed.

I am trying to implement only onCancel for now. Please do tell if onDismiss is needed to be implemented in some different way. Following the solution here, this is how I have coded the Fragment:

class MyFragment: Fragment(), DialogInterface.OnCancelListener {

    // other code

    private fun myFun() {
        // show progress dialog
        val myDialog = DialogProgress()
        myDialog.show(childFragmentManager, "null")

        // todo the long task of downloading something
        // myDialog.dismiss()
    }

    override fun onCancel(dialog: DialogInterface?) {
        // User canceled the dialog
        Toast.makeText(activity, "Process canceled by user!", Toast.LENGTH_SHORT).show()
        // todo
    }

}

And this is my DialogFragment code:

class DialogProgress: DialogFragment() {

    override fun onCancel(dialog: DialogInterface?) {
        super.onCancel(dialog)
        // need help here
    }

    override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
        super.onCreateDialog(savedInstanceState)

        // show progress dialog
        val v = activity!!.layoutInflater.inflate(R.layout.dialog_progress, null)
        v.findViewById<TextView>(R.id.progress_message).text = "Fetching data"

        return activity!!.let {
            val builder = AlertDialog.Builder(it, R.style.ThemeOverlay_AppCompat_Dialog)
            builder
                .setView(progressView)
                .create()
        }

    }
}

For the above code where I need help, I don't know how to convert the following Java code from the link of solution given above into kotlin:

@Override
public void onDismiss(final DialogInterface dialog) {
    super.onDismiss(dialog);
    Fragment parentFragment = getParentFragment();
    if (parentFragment instanceof DialogInterface.OnDismissListener) {
        ((DialogInterface.OnDismissListener) parentFragment).onDismiss(dialog);
    } 
}

Note that this is for onDismiss, I want it for onCancel.

score 0 · Accepted Answer · answered Jun 16 '19 at 23:24

The Java code can be simply converted into kotlin code by pasting it into the Android Studio and a pop-up should appear. This is the conversion of the java code:

override fun onCancel(dialog: DialogInterface?) {
    super.onCancel(dialog)
    val parentFragment = parentFragment
    if (parentFragment is DialogInterface.OnCancelListener) {
        (parentFragment as DialogInterface.OnCancelListener).onCancel(dialog)
    }
}

How to override onCancel in Dialog Fragment in Android in kotlin?

1 Answers1