Flutter crossAxisAlignment vs mainAxisAlignment

问题

I'm confused about crossAxisAlignment and mainAxisAlignment. Can anyone please explain it in simple words?

回答1:

For Row:

mainAxisAlignment = Horizontal Axis
crossAxisAlignment = Vertical Axis

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For Column:

mainAxisAlignment = Vertical Axis
crossAxisAlignment = Horizontal Axis

Image source

回答2:

Row/Column are associated to an axis:

• Horizontal for Row
• Vertical for Column

mainAxisAlignment is how items are aligned on that axis. crossAxisAlignment is how items are aligned on the other axis.

回答3:

This two pictures are clear to show the meaning of MainAxisAlignment and CrossAxisAlignment.

(Pictures are from Network)

回答4:

When you use a Row, its children are laid out in a row, which is horizontally. So a Row's main axis is horizontal. Using mainAxisAlignment in a Row lets you align the row's children horizontally (e.g. left, right). The cross axis to a Row's main axis is vertical. So using crossAxisAlignment in a Row lets you define, how its children are aligned vertically.

In a Column, it's the opposite. The children of a column are laid out vertically, from top to bottom (per default). So its main axis is vertical. This means, using mainAxisAlignment in a Column aligns its children vertically (e.g. top, bottom) and crossAxisAlignment defines how the children are aligned horizontally in that Column.

回答5:

In a column,

• to center(or align) vertically, mainAxisAlignment is used.
• to center(or align) horizontally, crossAxisAlignment is used.

In a row,

• to center(or align) horizontally, mainAxisAlignment is used.
• to center(or align) vertically, crossAxisAlignment is used.

来源：https://stackoverflow.com/questions/53850149/flutter-crossaxisalignment-vs-mainaxisalignment