All the code for handling collisions will go in the detectCollisions method. There is quite a large amount of code so let's split it up into two parts.
And once we have added the code for each part we will further sub-divide it to make sure we know how it works.
To get started, add the following code. Study it in detail as you proceed and note where the comment // More code here next is.
private void detectCollisions(GameState gs,
ArrayList<GameObject> objects) {
// More code here soon
boolean collisionOccurred = false;
// Something collides with some part of
// the player most frames
// so, let's make some handy references
// Get a reference to the players position
// as we will probably need to update it
Transform playersTransform =
objects.get(LevelManager.PLAYER_INDEX)
.getTransform();
PlayerTransform playersPlayerTransform =
(PlayerTransform) playersTransform...