harmony 鸿蒙Statck Layout

2022-12-05
浏览 (589)

Statck Layout

The stack layout reserves an area on the screen to display elements in a component and allows the elements to be stacked. You can implement a stack layout through the <Stack> component, which provides a stack container where child components are successively stacked and the latter one overwrites the previous one.

Alignment

Child components in the container can be aligned in any of the alignment modes described in the table below.

Name	Description	Image
TopStart	Top start.
Top	Horizontally centered on the top.
TopEnd	Top end.
Start	Vertically centered start.
Center	Horizontally and vertically centered.
End	Vertically centered end.
BottomStart	Bottom start.
Bottom	Horizontally centered on the bottom.
BottomEnd	Bottom end.

Z-order Control

You can use the zIndex attribute to set the z-order of a component in the stacking context, so as to create a custom stacking order of the child components. A larger zIndex value indicates a higher display level.

In the statck layout, if the size of a component is greater than that of the one before it, the one before it is hidden.

Stack({ alignContent: Alignment.BottomStart }) {
    Column() {
      Text ('Stacked component 1').textAlign (TextAlign.End).fontSize (20)
    }.width(100).height(100).backgroundColor(0xffd306)
    Column() {
      Text ('Stacked component 2').fontSize (20)
    }.width(150).height(150).backgroundColor(Color.Pink)
    Column() {
      Text ('Stacked component 3').fontSize (20)
    }.width(200).height(200).backgroundColor(Color.Grey)
}.margin({ top: 100 }).width(350).height(350).backgroundColor(0xe0e0e0)

In the preceding figure, the size of the stacked component 3 is greater than that of all the components before it. Therefore, the first two components are completely hidden. To show these components, modify their zIndex attribute settings.

```ts
Stack({ alignContent: Alignment.BottomStart }) {
    Column() {
      Text ('Stacked component 1').textAlign (TextAlign.End).fontSize (20)
    }.width(100).height(100).backgroundColor(0xffd306).zIndex(2)
    Column() {
      Text ('Stacked component 2').fontSize (20)
    }.width(150).height(150).backgroundColor(Color.Pink).zIndex(1)
    Column() {
      Text ('Stacked component 3').fontSize (20)
    }.width(200).height(200).backgroundColor(Color.Grey)
}.margin({ top: 100 }).width(350).height(350).backgroundColor(0xe0e0e0)
```

![](figures/stack1.png)