Create Dialog without activity

Question

How can I implement such a dialog, no activity is running.
Is the activity invisible or what?

Answer 1

How can I implement such a dialog, no activity is running.

You can't.

Is the activity invisible or what?

Possibly, perhaps using Theme.Translucent.NoTitleBar .

More likely, what you think is a Dialog is really a dialog-themed Activity . The main themes (eg, Theme.Material , Theme.AppCompat ) have specific themes with Dialog in their names that cause the activity's window to not fill the entire screen.

Answer 2

In your dialog you need to set type of Window which dialog attached, as follows:

dialog.getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_ALERT);

Do not forget declaring android.permission.SYSTEM_ALERT_WINDOW permission in your manifest.