CODEWITHSUNDEEP
androidkotlin
Pratik Bhandari
Pratik Bhandari

Reputation: 268

Callback from dialog to activity in Kotlin

I have been facing some issues while converting my android JAVA code into KOTLIN. I want to show a Material Dialog on some condition and want control back to activity as soon as the user clicks on dialog's button.

My java code:

public static void showAlertPopup(Context context, String title, String message) {
    try {
        MaterialAlertDialogBuilder builder = new MaterialAlertDialogBuilder(context);
        builder.setTitle(title != null ? title : context.getString(R.string.alertTitle));
        builder.setMessage(message);
        builder.setCancelable(false);
        builder.setIcon(ContextCompat.getDrawable(context, R.drawable.ic_alert));
        builder.setPositiveButton(context.getString(R.string.txtNeutralBtn),
                (dialogInterface, i) -> dialogInterface.dismiss());
        builder.setBackground(ContextCompat.getDrawable(context, R.drawable.dialog_background));
        builder.show();
    } catch (Exception e) {
        DLiteLogger.WriteLog(MaterialDialogUtility.class, AppSettings.LogLevel.Error, e.getMessage());
    }
}

My conversion to Kotlin:

fun showErrorPopup(
    context: Context,
    message: String?,
    callback: OnPositiveButtonClickListener?
) {
        MaterialAlertDialogBuilder(context).also {
            it.setTitle(context.getString(R.string.errorTitle))
            it.setMessage(message)
            it.setCancelable(false)
            it.setIcon(ContextCompat.getDrawable(context, R.drawable.ic_error))
            it.setPositiveButton(context.getString(R.string.txtNeutralBtn))
            { dialogInterface: DialogInterface, _: Int ->
                if (callback != null) {
                    dialogInterface.dismiss()
                    callback.onPositiveBtnClick(dialogInterface)
                } else dialogInterface.dismiss()
            }
            it.background = ContextCompat.getDrawable(context, R.drawable.dialog_background)
            it.show()
        }
}

This is the interface I have created in same class:

interface OnPositiveButtonClickListener {
    fun onPositiveBtnClick(dialog: DialogInterface?)
}

The issue I am facing currently for below code:

MaterialDialogUtility.showErrorPopup(this@LoginActivity,
                        getString(R.string.alertIncorrectPassword),
                        { dialog ->
                            Objects.requireNonNull(binding.passwordEt.getText()).clear()
                        })

is

Type mismatch: inferred type is ([ERROR : ]) -> [ERROR : Cannot infer type variable TypeVariable(_L)] but MaterialDialogUtility.OnPositiveButtonClickListener? was expected

Upvotes: 0

Views: 1885

Answers (1)

Talha Mir
Talha Mir

Reputation: 1258

In order to use your interface as a lambda you'll have to convert it to a SAM interface a.k.a functional interface. So something like this:

fun interface OnPositiveButtonClickListener {
    fun onPositiveBtnClick(dialog: DialogInterface?)
}

More description about functional interfaces here.

If you don't want to use SAM you can still use your current interface like this:

showErrorPopup(
        this,
        "Some String",
        callback = object: OnPositiveButtonClickListener{
            override fun onPositiveBtnClick(dialog: DialogInterface?) {
                TODO("Not yet implemented")
            }

        }
    )

Upvotes: 1

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