How to dismiss a Alert Dialog in Mono for android correctly? - xamarin

Question

In my application i have a Custom AlertView, which works quite good so far. I can open it the first time, do, what i want to do, and then close it. If i want to open it again, i'll get
java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first
so, here some code:
public Class ReadingTab
{
...
private AlertDialog AD;
...
protected override void OnCreate(Bundle bundle)
{
btnAdd.Click += delegate
{
if (IsNewTask)
{
...
AlertDialog.Builer adb = new AlertDialog.Builer(this);
...
View view = LayoutInflater.Inflate(Resource.Layout.AlertDView15ET15TVvert, null);
adb.setView(view)
}
AD = adb.show();
}
}
}
that would be the rough look of my code.
Inside of btnAdd are two more buttons, and within one of them (btnSafe) i do AD.Dismiss() to close the Alert dialoge, adb.dispose() hasn't done anything.
the first time works fine, but when i call it the secon time, the debugger holds at AD = adb.show(); with the Exception mentioned above.
So what do i have to do, to remove the Dialoge from the parent? i can't find removeView() anywhere.

Answer 1

If you are setting up an AlertView once and then using it in multiple places (especially if you are using the same AlertView across different Activities) then you should consider creating a static AlertDialog class that you can then call from all over the place, passing in the current context as a parameter each time you want to show it. Then when a button is clicked you can simply dismiss the dialog and set the instance to null. Here is a basic example:
internal static class CustomAlertDialog
{
private static AlertDialog _instance;
private const string CANCEL = #"Cancel";
private const string OK = #"OK";
private static EventHandler _handler;
// Static method that creates your dialog instance with the given title, message, and context
public static void Show(string title,
string message,
Context context)
{
if (_instance != null)
{
throw new Exception(#"Cannot have more than one confirmation dialog at once.");
}
var builder = new AlertDialog.Builder(context);
builder.SetTitle(title);
builder.SetMessage(message);
// Set buttons and handle clicks
builder.SetPositiveButton(OK, delegate { /* some action here */ });
builder.SetNegativeButton(CANCEL, delegate { /* some action here */});
// Create a dialog from the builder and show it
_instance = builder.Create();
_instance.SetCancelable(false);
_instance.Show();
}
}
And from your Activity you would call your CustomAlertDialog like this:
CustomAlertDialog.Show(#"This is my title", #"This is my message", this);