Make QStateMachine inherit QState

This removes the need for a "root state" in the machine; or rather,
the machine _is_ the root state.
User code can now pass in a QStateMachine directly to the QState
constructor, instead of machine->rootState().
This also means we could get rid of the "proxying" from the machine
to the root state for things like properties (initialState et al),
finished() signal and auto-reparenting of states (the ChildAdded
event hack).
A fun little side-effect of this change is that it's now possible
to embed state machines within state machines. We can't think of
a good use case yet where you would rather embed a stand-alone
state machine (with its own event processing etc.) rather than
having just a regular nested state, but it's neat and it works.

Reviewed-by: Eskil Abrahamsen Blomfeldt

1 files changed, 3 insertions, 3 deletions

diff --git a/examples/animation/sub-attaq/submarine.cpp b/examples/animation/sub-attaq/submarine.cpp
index 04b7916..78a9539 100644
--- a/examples/animation/sub-attaq/submarine.cpp
+++ b/examples/animation/sub-attaq/submarine.cpp
@@ -115,7 +115,7 @@ SubMarine::SubMarine(int type, const QString &name, int points, QGraphicsItem *
     QStateMachine *machine = new QStateMachine(this);
 
     //This state is when the boat is moving/rotating
-    QState *moving = new QState(machine->rootState());
+    QState *moving = new QState(machine);
 
     //This state is when the boat is moving from left to right
     MovementState *movement = new MovementState(this, moving);
@@ -132,7 +132,7 @@ SubMarine::SubMarine(int type, const QString &name, int points, QGraphicsItem *
     machine->setInitialState(moving);
 
     //End
-    QFinalState *final = new QFinalState(machine->rootState());
+    QFinalState *final = new QFinalState(machine);
 
     //If the moving animation is finished we move to the return state
     movement->addTransition(movement, SIGNAL(animationFinished()), rotation);
@@ -141,7 +141,7 @@ SubMarine::SubMarine(int type, const QString &name, int points, QGraphicsItem *
     rotation->addTransition(rotation, SIGNAL(animationFinished()), movement);
 
     //This state play the destroyed animation
-    QAnimationState *destroyedState = new QAnimationState(machine->rootState());
+    QAnimationState *destroyedState = new QAnimationState(machine);
     destroyedState->setAnimation(setupDestroyAnimation(this));
 
     //Play a nice animation when the submarine is destroyed