Multi-Child Algorithm Deep Dive
summary
Breaks down the actual Flutter flex layout rules into the six-step multi-child layout algorithm, showing how unflexed children are measured first, leftover space is divided by flex factors, and flex-fit controls whether reserved space is forced. Explains mainAxisSize max vs min and cross-axis extent behavior, and runs a concrete example: a 900-high column with a 300 fixed child plus an expanded and a flexible child where 600 is reserved, expanded consumes its 300 reserved but the flexible only uses 150. Highlights surprising result that flexes reserve space but may not occupy it and that flex fit tight vs loose is the single difference between Expanded and Flexible.
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chapters (12)
- 0:00Introduction
- 1:04Flex terminology explained
- 3:52Magic smoke in layout
- 4:34Six-step multi-child layout
- 9:11Tight vs loose constraints
- 12:02Cross-axis extent in flex
- 13:27Main axis extent in flex
- 16:01Flex layout example
- 18:52Final positioning step
- 21:50Cross-axis alignment edge cases
- 23:37Flex tongue twister revisited
- 25:02Help and resources
