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1# Stack Layout (Stack)
2
3
4## Overview
5
6The 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>](../reference/arkui-ts/ts-container-stack.md) component, which provides a stack container where positioned or non-positioned child elements are pushed successively and the latter one sits on top of the previous one.
7
8The stack layout excels at page stacking and positioning, and is widely used in ad and widget arrangement.
9
10In the **\<Stack>** component shown in Figure 1, the sequence of child elements is Item1 -> Item2 -> Item3.
11
12
13  **Figure 1** Stack layout
14
15![stack-layout](figures/stack-layout.png)
16
17
18## How to Develop
19
20The **\<Stack>** component can contain various child elements, which are stacked in the center by default. While respecting the constraints of **\<Stack>**, child elements are laid out in their respective style.
21
22
23
24```ts
25let MTop:Record<string,number> = { 'top': 50 }
26Column(){
27  Stack({ }) {
28    Column(){}.width('90%').height('100%').backgroundColor('#ff58b87c')
29    Text('text').width('60%').height('60%').backgroundColor('#ffc3f6aa')
30    Button('button').width('30%').height('30%').backgroundColor('#ff8ff3eb').fontColor('#000')
31  }.width('100%').height(150).margin(MTop)
32}
33```
34
35
36![stack-layout-sample](figures/stack-layout-sample.png)
37
38
39## Alignment
40
41Alignment of elements in the **\<Stack>** component is set through the [alignContent](../reference/arkui-ts/ts-appendix-enums.md#alignment) parameter. As shown in Figure 2, nine alignment modes are supported.
42
43  **Figure 2** Alignment modes in the \<Stack> component
44
45![en-us_image_0000001562940621](figures/en-us_image_0000001562940621.png)
46
47
48## Z-order Control
49
50The stacking order of child elements in the **\<Stack>** component is set through the **[zIndex](../reference/arkui-ts/ts-universal-attributes-z-order.md)** attribute. A larger **zIndex** value indicates a higher display level.
51
52  In the stack layout, if the size of an element is greater than that of the one before it, the one before it is hidden.
53
54```ts
55let MTopM1:Record<string,number> = { 'top': 100 }
56Stack({ alignContent: Alignment.BottomStart }) {
57  Column() {
58    Text ('Stacked element 1').textAlign (TextAlign.End).fontSize (20)
59  }.width(100).height(100).backgroundColor(0xffd306)
60
61  Column() {
62    Text ('Stacked element 2').fontSize (20)
63  }.width(150).height(150).backgroundColor(Color.Pink)
64
65  Column() {
66    Text ('Stacked element 3').fontSize (20)
67  }.width(200).height(200).backgroundColor(Color.Grey)
68}.margin(MTopM1).width(350).height(350).backgroundColor(0xe0e0e0)
69```
70
71![en-us_image_0000001511900544](figures/en-us_image_0000001511900544.png)
72
73In the following figure, the size of the stacked element 3 is greater than that of all the elements before it. Therefore, the first two elements are completely hidden. To show these elements, modify their **zIndex** attribute settings.
74
75
76```ts
77let MTopM:Record<string,number> = { 'top': 100 }
78Stack({ alignContent: Alignment.BottomStart }) {
79  Column() {
80    Text ('Stacked element 1').fontSize (20)
81  }.width(100).height(100).backgroundColor(0xffd306).zIndex(2)
82
83  Column() {
84    Text ('Stacked element 2').fontSize (20)
85  }.width(150).height(150).backgroundColor(Color.Pink).zIndex(1)
86
87  Column() {
88    Text ('Stacked element 3').fontSize (20)
89  }.width(200).height(200).backgroundColor(Color.Grey)
90}.margin(MTopM).width(350).height(350).backgroundColor(0xe0e0e0)
91```
92
93![en-us_image_0000001563060797](figures/en-us_image_0000001563060797.png)
94
95
96## Example Scenario
97
98In this example, the stack layout is used to quickly set up a page.
99
100
101```ts
102@Entry
103@Component
104struct StackSample {
105  private arr: string[] = ['APP1', 'APP2', 'APP3', 'APP4', 'APP5', 'APP6', 'APP7', 'APP8'];
106
107  build() {
108    Stack({ alignContent: Alignment.Bottom }) {
109      Flex({ wrap: FlexWrap.Wrap }) {
110        ForEach(this.arr, (item:string) => {
111          Text(item)
112            .width(100)
113            .height(100)
114            .fontSize(16)
115            .margin(10)
116            .textAlign(TextAlign.Center)
117            .borderRadius(10)
118            .backgroundColor(0xFFFFFF)
119        }, (item:string):string => item)
120      }.width('100%').height('100%')
121
122      Flex({ justifyContent: FlexAlign.SpaceAround, alignItems: ItemAlign.Center }) {
123        Text ('Contacts').fontSize (16)
124        Text ('Settings').fontSize (16)
125        Text ('Messaging').fontSize (16)
126      }
127      .width('50%')
128      .height(50)
129      .backgroundColor('#16302e2e')
130      .margin({ bottom: 15 })
131      .borderRadius(15)
132    }.width('100%').height('100%').backgroundColor('#CFD0CF')
133  }
134}
135```
136
137
138![en-us_image_0000001511421368](figures/en-us_image_0000001511421368.png)
139