Android Material Design 笔记 --- Metrics & keylines

屏幕上的元件要为8dp的倍数， 工具栏上的元件要为4dp的倍数。

元件比率  Ratio keylines：

• 16:9
• 3:2
• 4:3
• 1:1
• 3:4
• 2:3

Width = Aspect ratio * Height

Height = Width/Aspect ratio

Touch target size （可触碰对象的大小，如按钮之类的元件）

To ensure balanced information density and usability, touch targets should be at least 48 x 48 dp. In most cases, there should be 8dp or more space between them.

参考：

https://material.io/guidelines/layout/metrics-keylines.html#metrics-keylines-touch-target-size