Tiled Map Collision Detection Help

[wreed12345]

Hello forum, recently I began to use a Tiled map for my game. I was thinking about using a more traditional AABB collision method but then found out I can get tile ID’s and so I would imagine I could figure out collision that way. I was trolling through past posts about Tiled and collision detection and came upon this:

@matheus23

Moving on. This is you would get the ID of a Tile with libgdx:

// First, we need to get the layer in which you create the tiles.
// In this case I assume you call the layer 'collision' layer in Tiled.
private int computeCollisionLayerIndex(TiledMap map) {
    for (int i = 0; i < map.getLayers().getCount(); i++) {
        // This is used to get the layer with the name "collision" from all layers
        // (The layers name in Tiled)
        if (map.getLayers().get(i).getName().equalsIgnoreCase("collision")) {
            return i;
        }
    }
    return -1;
}

// Now we surround getting the layer from the index
// with a little error handling:
public void whatevername(TiledMap map) {
    int collisionLayerIndex = computeCollisionLayerIndex(map);
    if (collisionLayerIndex != -1) {
        MapLayer layer = map.getLayers().get(collisionLayerIndex
        if (layer instanceof TiledMapTileLayer) {
            getCollisionTilesFrom((TiledMapTileLayer) layer);
        } else throw some kind of error
    } else throw some kind of error
}

// And finally we print the ID of each tile in the layer
// I don't know what you would do with the tiles in the end,
// and since I don't know what tile ID's your tiles have,
// I simply print them.
public void getCollisionTilesFrom(TiledMapTileLayer layer) {
    for (int x = 0; x < layer.getWidth(); x++) {
        for (int y = 0; y < layer.getHeight(); y++) {
            TiledMapTileLayer.Cell cell = layer.getCell(x, y);
            if (cell == null) continue; // There is no cell
            if (cell.getTile() == null) continue; // No tile inside cell
            
            System.out.println(cell.getTile().getID()); // Get the ID.
        }
    }
}

With this code in particular

 TiledMapTileLayer.Cell cell = layer.getCell(x, y);

You can get the ID from a specific cell. Now for the questions:

1. What would the cell ID turn up as ? A number or some string - how would this be relevant to what is exactly placed?
2. After I figure out when my player is next to a certain tile, how could i prevent the player from moving onto that tile? Would there be a simple way to determine if the tile is to the left of the character, and making a variable like isAbleToMoveLeft set to false if its near a tile where it can not move left.Maybe something like this?

if(collisionTile.x < player.x){
     isAbleToMoveLeft = false;
}

3. Final question is this: I have items drawn in 4 layers in Tiled. Is this something that will effect the way collision detection works? In the method written by matheus23 the getCollisionTilesFrom method requires a layer. So I am curious if 4 layers will create problems.

Thanks for the help! 8)