How to return to input UI when I input error password when I use AlertDialog in Kotlin?

Question

I hope to a password input dialog box is opened when I start an APP.

If I input the correct password, the dialog will close and display main UI.

If I input the error password, the dialog will keep open and require a user input again.

How can I do it? Thanks!

At present, the dialog is always closed no matter I input correct or error password.

  override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.layout_main)      
        showInputPasswordDialog()
    }  


    private fun showInputPasswordDialog {    
        val editText = EditText(this)
        val inputDialog = AlertDialog.Builder(this)
        inputDialog.setTitle("Input")
                   .setView(editText)
                   .setCancelable(false)
                   .setNegativeButton("Cancel", DialogInterface.OnClickListener { dialog, which ->
                           finish();
                   })

        inputDialog.setPositiveButton("OK",
                DialogInterface.OnClickListener { dialog, which ->
                    val password= editText.text.toString()
                    if (password=="aa"){
                        //close the dialog
                    }else{
                        toast("Password error")
                        //Return for input again
                    }
                }).show()
    }

`AlertDialog` will automatically close itself on built-in button clicked like Positive, Neutral or Negative buttons. So 2 options: 1/ Custom a `Dialog` with your desired layout and logic. 2/ Manage the buttons separately without using built-in `AlertDialog` buttons — Tam Huynh, Jun 05 '18 at 04:07

score 2 · Accepted Answer · answered Jun 05 '18 at 04:47

If you handle the onclick listener for positive button inside alertDialog.onShowlistener , then you can avoid the dialog closing flow.Please find the modified code below.

override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.layout_main)      
        showInputPasswordDialog()
    }  


    private fun showInputPasswordDialog {    
        val editText = EditText(this)
        val inputDialog = AlertDialog.Builder(this)
        inputDialog.setTitle("Input")
                   .setView(editText)
                   .setCancelable(false)
                   .setNegativeButton("Cancel", DialogInterface.OnClickListener { dialog, which ->
                           finish();
                   })

        inputDialog.setPositiveButton("OK",null)

       // modified code starts here
        val mAlertDialog = inputDialog.create()

        mAlertDialog.setOnShowListener(DialogInterface.OnShowListener {
        val b = mAlertDialog.getButton(AlertDialog.BUTTON_POSITIVE)
        b.setOnClickListener(View.OnClickListener {

          val password= editText.text.toString()
                if (password=="aa"){
                    mAlertDialog.dismiss();
                    //close the dialog
                }else{
                    toast("Password error")
                    //Return for input again
                }

        })
    })

    mAlertDialog.show() 

    }

ref: How to prevent a dialog from closing when a button is clicked

How to return to input UI when I input error password when I use AlertDialog in Kotlin?

1 Answers1