LibGDX - Ending a Level and breaking out of Render() - libgdx

Question

The basic idea of the game is to collect all the items in a room in order to proceed to the next. Not very original I know... When the items are all collected, a screen will be displayed stating "Level Complete" and then after a few seconds the next level will be reloaded. The problem I am having is that when I land on the last item, and the check "have all the items been collected?" rule is satisfied the game suddenly freezes, well starts to shake actually. The player sprite is frozen in place, as is the item, and the game can no longer be interacted with. I can only assume that the game is getting trapped inside the render() method and is not escaping, or is satisfying the same condition over again.
Does anyone have any ideas on how to break out of the main render() method correctly to traverse to a new screen?
In my main render() method I have a call to another method which checks the gamestate, ie, have all of the items been collected in the room...
render() {
... code ...
checkGameState()
}
And then checkGameState() looks as follows:
public void checkGameState()
{
//If the player has collected all of the items on a level then do something
//if(stats.getItemsCollected() == stats.getTotalItems()) {
//reset some stuff
stats.resetItems();
stats.incLevel();
//show the intermediate screen or menu screen
//load the next level
showLevelCompleteScreen();
//
}
}
The ShowLevelCompleteScreen() method simply attempts to switch screens as follows:
public void showLevelComplete()
{
game.setScreen(SuperBlockMan.LevelComplete);
}

Answer 1

First I'd advise you to not reset your Screen, but to dispose() it correctly and then create a completely new one after one level finished. That saves you from bugs due to incorrect resetting.
After you switched the Screen to LevelComplete, the rendering will not stop, but libGDX will start to call render of your LevelComplete Screen.
As for the freezing of your character, item and so on, I guess you do not call Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT); in the render method of your LevelComplete Screen and that's why you can still see everything from your game, but cannot interact anymore.