Improve selection of states

[Matthias Schoettle]

When working with state views and having to select one to be able to create transitions between states, once one state is selected the only way to deselect it is to tap somewhere else. If another state is tapped, nothing happens. Also, tap-and-hold on a state only works when no state is currently selected.

(state refers to the view representing a state called StateComponentView)

I propose the following improvements in order to streamline editing:

• tapping on a state either
  • deselects a currently selected state and selects the tapped state
  • selects the state (i.e., multiple states can be selected to move them around at once [like classes])
• tapping on a selected state deselects it again
• tap-and-holding on a state is not dependent on any selected state(s)

[Matthias Schoettle]

Resolved issue #218: Improvement state selection behaviour:

• tap-and-hold is now independent of selection state
• tapping on an already selected state deselects it
• tapping on a (not selected) state selects it and deselects any other selected state

→ <<cset 6411ac3a0ed0>>

[Matthias Schoettle]

References issue #218: Selection behaviour needed to be brought back, because transitions couldn't be created anymore (would always create a self-transition on the second state).

Only one state can be selected for now.

A better behaviour is necessary, perhaps like classes and associations.

→ <<cset 79d57a47faa6>>

[Matthias Schoettle]

References issue #218: The TextViewHandler should not pretend to have handled events that were not handled (tap events). This allows, for example, to tap on a state or class name and it will be selected.

→ <<cset 7e506fafbc6e>>