Part Four: Learning How to Code

Adding a Button

• Navigate to the standard palette.
• Add a TButton component.
• Change name:
  • Default: Button1
  • New: btnChangeHair
• Modify the caption:
  • Display: Change Hair

Methods and Events

• Focus: Button actions.
• Access events via the object inspector.
  • Example: OnClick event.
• Double-click to access code area.

Writing Code for Events

• Code executes between begin and end keywords.
• Event-driven programming:
  • Events: Trigger code execution.
  • Order of clicking affects execution sequence.

Coding Syntax

• Structure of statements:
  • Syntax: [object].[property] := [new_value];
  • Example:
    • shpTongue.Visible := False;
    • shpHair.Brush.Color := clWhite;
• Importance of matching types (e.g., True/False for Visible).

Example: Positioning and Movement

• Properties: Top and Left.
  • move right to get the “left” property to be bigger and then move right to get the “left” property smaller
  • move down to get the “top“ property bigger than move up to get the” top” property smaller
• Button example:
  • Button name: btnMoveLeftEye
  • Code: Move shapes by changing Left property.

Design vs. Runtime

• Design Time:

  • Is when you change properties in the object inspector

• Runtime:

  Is When you change properties using code