The GUI (Graphic User Interface) is a game mechanic in that displays information required by the Player for gameplay. All parts of the GUI can be hidden by selecting Hide GUI in the Settings.
Health Bar - The Player's health bar displays how much Health he/she has.
Hunger Bar - The Player's hunger bar displays how much Hunger he/she has, and can be regenerated by eating Food. If their hunger is over 8 (), they will regenerate health. Movement and some other activities will decrease the Hunger Bar.
Armor Bar - Indicates the level of protection the Armor gives the Player. It can be found on the top left corner directly below the Health Bar. Only shown if the Player wears Armor.
Experience Bar - The Player's experience bar displays the experience level of a Player, and the progress towards next level. Experience increases by performing certain actions (killing Mobs, mining, etc.), and decreases when Enchanting or repairing items through an Anvil. Progress towards next level will demand more experience orbs, the higher level the Player already has.
Hotbar - The Hotbar gives the Player quick access to some of the items in their Inventory. The items can be organised by accessing the Inventory, using the rightmost button in the Hotbar.
Action Pad/D-Pad - The arrows are used for Movement extra buttons are used for jumping and sneaking/crouching.
Oxygen Bar - Appears in the form of air bubbles that appear below the Hunger Bar. It indicates how much time the Player has before the Player starts taking damage due to lack of air.
Jump Bar - Appears when the Player is riding a Horse or Pig and starts to jump, and will replace the experience bar in Survival. It indicates the charge of a jump. Timing it correctly can increase the height of the jump.
Buttons - The Pause and Chat Button give access to the Options menu and Chat Interface respectively.
Interaction Button - Buttons that appear when going near certain Items or Mobs to do actions, such as the Sit and Stand button when going near tamed Wolves and Ocelots, or the Ride button when going near a rideable entity, etc. It is located above the Experience Bar.
Effects - Indicators below the Hunger Bar are displayed if the Player are affected by Status Effects. The indicators can be tapped to show time left of effect.
Extra Health Bar - When riding a Horse or a Pig, an extra bar showing the health of the animal is shown below the Player's Hunger bar.
The pause button will not pause time or progression in-game, as Mobs and entity will still move, unlike Console and PC.
It is possible to interact with certain Mobs, Blocks, or entities without using the interaction button. The Player needs to tap and hold the Mob, Block, or entity to interact with it.
As of Update 1.0.4, the Armor GUI was moved slightly upwards, closer to the Health Bar.
As of Update 1.1, the Health, Hunger, Oxygen, and Armor Bars will appear directly over the Hotbar if the Player has selected Classic UI over Pocket UI.