How do I display an alert dialog on Android?

Question

I want to display a dialog/popup window with a message to the user that shows "Are you sure you want to delete this entry?" with one button that says 'Delete'. When Delete is touched, it should delete that entry, otherwise nothing.

I have written a click listener for those buttons, but how do I invoke a dialog or popup and its functionality?

Answer 1

You could use an AlertDialog for this and construct one using its Builder class. The example below uses the default constructor that only takes in a Context since the dialog will inherit the proper theme from the Context you pass in, but there's also a constructor that allows you to specify a specific theme resource as the second parameter if you desire to do so.

new AlertDialog.Builder(context)
    .setTitle("Delete entry")
    .setMessage("Are you sure you want to delete this entry?")

    // Specifying a listener allows you to take an action before dismissing the dialog.
    // The dialog is automatically dismissed when a dialog button is clicked.
    .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int which) { 
            // Continue with delete operation
        }
     })

    // A null listener allows the button to dismiss the dialog and take no further action.
    .setNegativeButton(android.R.string.no, null)
    .setIcon(android.R.drawable.ic_dialog_alert)
    .show();