Tell me about methods that redraw the View.

Methods:

• invalidate(): Marks the View as "dirty", requiring redraw. Schedules onDraw() to be called in the future. Redraw occurs on the main thread. Used when external properties of the View (color, background, etc.) change.
• postInvalidate(): Similar to invalidate(), but can be called from any thread, not just the main thread. Safe to use in background threads.
• requestLayout(): Marks the View as "invalid", requiring recalculation of its size and position. Schedules onMeasure() and onLayout(), then onDraw(). Used when the size or position of the View changes (e.g., when adding/removing child elements in a ViewGroup).

Comparison of methods:

Method	Calling thread	Layout recalculation	Redraw
invalidate()	UI thread	No	Yes
postInvalidate()	Any thread	No	Yes
requestLayout()	UI thread	Yes	Yes (after layout)

Example of using invalidate():

// Change the color of the View and request redraw
myView.setBackgroundColor(Color.RED)
myView.invalidate()

Example of using requestLayout():

// Add a child element to LinearLayout and request layout recalculation and redraw
val newTextView = TextView(context)
linearLayout.addView(newTextView)
linearLayout.requestLayout()