UI to invoke activity in fragment

An interface is defined within a 1:fragment, or an interface is defined externally,

2:fragment defining an Interface object's properties

3:activity implement this interface

The Onattach method of 4:fragment is the interface of the strong transfer activity

For example:

@Override
public void Onattach (activity activity)
{
Super.onattach (activity);

Try
{
Onfragmentchangelistener = (onfragmentchangelistener) activity;
}
catch (ClassCastException e)
{
throw new ClassCastException (activity.tostring () + "must implement Onfragmentchangelistener");
}
}

UI to invoke activity in fragment