harmony 鸿蒙Alert Dialog Box

2022-08-09
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Alert Dialog Box

You can set the text content and response callback for an alert dialog box.

NOTE

The APIs of this module are supported since API version 7. Updates will be marked with a superscript to indicate their earliest API version.

The functionality of this module depends on UI context. This means that the APIs of this module cannot be used where the UI context is unclear. For details, see UIContext.

Since API version 10, you can use the showAlertDialog API in UIContext to obtain the UI context.

Attributes

Name	Type	Description
show	AlertDialogParamWithConfirm \|AlertDialogParamWithButtons \|AlertDialogParamWithOptions	Defines and displays the <AlertDialog> component.

AlertDialogParamWithConfirm

Name	Type	Mandatory	Description
title	ResourceStr	No	Title of the dialog box.
subtitle¹⁰⁺	ResourceStr	No	Subtitle of the dialog box.
message	ResourceStr	Yes	Content of the dialog box.
autoCancel	boolean	No	Whether to close the dialog box when the overlay is clicked. Default value: true
confirm	{ enabled¹⁰⁺?: boolean, defaultFocus¹⁰⁺?: boolean, style¹⁰⁺?: DialogButtonStyle, value: ResourceStr, fontColor?: ResourceColor, backgroundColor?: ResourceColor, action: () => void }	No	Information about the confirm button. enabled: whether to respond when the button is clicked. Default value: true defaultFocus: whether the button is the default focus. Default value: false style: button style. Default value: DialogButtonStyle.DEFAULT value: text of the button. fontColor: font color of the button. backgroundColor: background color of the button. action: callback when the button is selected.
cancel	() => void	No	Callback invoked when the dialog box is closed after the overlay is clicked.
alignment	DialogAlignment	No	Alignment mode of the dialog box in the vertical direction. Default value: DialogAlignment.Default
offset	Offset	No	Offset of the dialog box relative to the alignment position. Default value: { dx: 0 , dy: 0 }
gridCount	number	No	Number of grid columns occupied by the width of the dialog box. Default value: 4
maskRect¹⁰⁺	Rectangle	No	Mask area of the dialog box. Events outside the mask area are transparently transmitted, and events within the mask area are not. Default value: { x: 0, y: 0, width: ‘100%’, height: ‘100%’ }

Priorities of the confirm parameters: fontColor and backgroundColor > style > defaultFocus

backgroundColor	fontColor	style	defaultFocus	Effect
Green	Red	-	-	Red text on green background
Green	-	DialogButtonStyle.HIGHLIGHT	-	White text on green background
Green	-	DialogButtonStyle.DEFAULT	-	Blue text on green background
Green	-	-	TRUE	White text on green background
Green	-	-	FALSE/-	Blue text on green background
-	Red	DialogButtonStyle.HIGHLIGHT	-	Red text on blue background
-	Red	DialogButtonStyle.DEFAULT	-	Red text on white background
-	Red	-	TRUE	Red text on blue background
-	Red	-	FALSE/-	Red text on white background
-	-	DialogButtonStyle.HIGHLIGHT	-	White text on blue background
-	-	DialogButtonStyle.DEFAULT	-	Blue text on white background
-	-	-	TRUE	White text on blue background
-	-	-	FALSE/-	Blue text on white background

AlertDialogParamWithButtons

Name	Type	Mandatory	Description
title	ResourceStr	No	Title of the dialog box.
subtitle¹⁰⁺	ResourceStr	No	Subtitle of the dialog box.
message	ResourceStr	Yes	Content of the dialog box.
autoCancel	boolean	No	Whether to close the dialog box when the overlay is clicked. Default value: true
primaryButton	{ enabled¹⁰⁺?: boolean, defaultFocus¹⁰⁺?: boolean, style¹⁰⁺?: DialogButtonStyle, value: ResourceStr, fontColor?: ResourceColor, backgroundColor?: ResourceColor, action: () => void; }	No	Information about the confirm button. enabled: whether to respond when the button is clicked. Default value: true defaultFocus: whether the button is the default focus. Default value: false style: button style. Default value: DialogButtonStyle.DEFAULT value: text of the button. fontColor: font color of the button. backgroundColor: background color of the button. action: callback when the button is selected.
secondaryButton	{ enabled¹⁰⁺?: boolean, defaultFocus¹⁰⁺?: boolean, style¹⁰⁺?: DialogButtonStyle, value: ResourceStr, fontColor?: ResourceColor, backgroundColor?: ResourceColor, action: () => void; }	No	Information about the confirm button. enabled: whether to respond when the button is clicked. Default value: true defaultFocus: whether the button is the default focus. Default value: false style: button style. Default value: DialogButtonStyle.DEFAULT value: text of the button. fontColor: font color of the button. backgroundColor: background color of the button. action: callback when the button is selected.
cancel	() => void	No	Callback invoked when the dialog box is closed after the overlay is clicked.
alignment	DialogAlignment	No	Alignment mode of the dialog box in the vertical direction. Default value: DialogAlignment.Default
offset	Offset	No	Offset of the dialog box relative to the alignment position.
gridCount	number	No	Number of grid columns occupied by the width of the dialog box.
maskRect¹⁰⁺	Rectangle	No	Mask area of the dialog box. Events outside the mask area are transparently transmitted, and events within the mask area are not. Default value: { x: 0, y: 0, width: ‘100%’, height: ‘100%’ }

AlertDialogParamWithOptions¹⁰⁺

Name	Type	Mandatory	Description
title	ResourceStr	No	Title of the dialog box.
subtitle¹⁰⁺	ResourceStr	No	Subtitle of the dialog box.
message	ResourceStr	Yes	Content of the dialog box.
autoCancel	boolean	No	Whether to close the dialog box when the overlay is clicked. Default value: true
cancel	() => void	No	Callback invoked when the dialog box is closed after the overlay is clicked.
alignment	DialogAlignment	No	Alignment mode of the dialog box in the vertical direction. Default value: DialogAlignment.Default
offset	Offset	No	Offset of the dialog box relative to the alignment position.
gridCount	number	No	Number of grid columns occupied by the width of the dialog box.
maskRect¹⁰⁺	Rectangle	No	Mask area of the dialog box. Events outside the mask area are transparently transmitted, and events within the mask area are not. Default value: { x: 0, y: 0, width: ‘100%’, height: ‘100%’ }
buttons¹⁰⁺	Array<AlertDialogButtonOptions>	No	Buttons in the dialog box.
buttonDirection¹⁰⁺	DialogButtonDirection	No	Direction in which buttons are laid out. Default value: DialogButtonDirection.AUTO When there are more than three buttons, the Auto mode (which automatically switches to the vertical layout when there are more than two buttons) is recommended. In non-Auto mode, buttons that extend beyond the display area are clipped.

AlertDialogButtonOptions¹⁰⁺

Name	Type	Mandatory	Description
enabled	boolean	No	Whether to respond when the button is clicked. Default value: true
defaultFocus	boolean	No	Whether the button is the default focus. Default value: false
style	DialogButtonStyle	No	Style of the button. Default value: DialogButtonStyle.DEFAULT
value	ResourceStr	Yes	Text of the button. If the value is null, the button is not displayed.
fontColor	ResourceColor	No	Font color of the button.
backgroundColor	ResourceColor	No	Background color of the button.
action	() => void	Yes	Callback when the button is selected.

DialogButtonDirection¹⁰⁺

Name	Description
AUTO	Buttons are laid out horizontally when there are two or fewer buttons and vertically otherwise.
HORIZONTAL	Buttons are laid out horizontally.
VERTICAL	Buttons are laid out vertically.

Priorities of the confirm parameters: fontColor and backgroundColor > style > defaultFocus

backgroundColor	fontColor	style	defaultFocus	Effect
Green	Red	-	-	Red text on green background
Green	-	DialogButtonStyle.HIGHLIGHT	-	White text on green background
Green	-	DialogButtonStyle.DEFAULT	-	Blue text on green background
Green	-	-	TRUE	White text on green background
Green	-	-	FALSE/-	Blue text on green background
-	Red	DialogButtonStyle.HIGHLIGHT	-	Red text on blue background
-	Red	DialogButtonStyle.DEFAULT	-	Red text on white background
-	Red	-	TRUE	Red text on blue background
-	Red	-	FALSE/-	Red text on white background
-	-	DialogButtonStyle.HIGHLIGHT	-	White text on blue background
-	-	DialogButtonStyle.DEFAULT	-	Blue text on white background
-	-	-	TRUE	White text on blue background
-	-	-	FALSE/-	Blue text on white background

DialogAlignment

Name	Description
Top	Vertical top alignment.
Center	Vertical center alignment.
Bottom	Vertical bottom alignment.
Default	Default alignment.
TopStart⁸⁺	Top left alignment.
TopEnd⁸⁺	Top right alignment.
CenterStart⁸⁺	Center left alignment.
CenterEnd⁸⁺	Center right alignment.
BottomStart⁸⁺	Bottom left alignment.
BottomEnd⁸⁺	Bottom right alignment.

Rectangle¹⁰⁺

The Rectangle type is used to represent a mask area of a dialog box.

Name	Type	Mandatory	Description
x	Length	No	X coordinate of the mask area of the dialog box relative to the upper left corner of the window. Default value: 0vp
y	Length	No	Y coordinate of the mask area of the dialog box relative to the upper left corner of the window. Default value: 0vp
width	Length	No	Width of the mask area of the dialog box. Default value: ‘100%’
height	Length	No	Height of the mask area of the dialog box. Default value: ‘100%’

NOTE

x and y can be set to a positive or negative percentage value. When x is set to ‘100%’, the mask area is moved rightward by the window width. When x is set to ’-100%’, the mask area is moved leftward by the window width. When y is set to ‘100%’, the mask area is moved downward by the window height. When y is set to ’-100%’, the mask area is moved upward by the window height.

width and height can be set in percentage and can only be set to positive values. If they are set to negative values, the default values are used instead.

The percentage is calculated based on the width and height of the window.

DialogButtonStyle¹⁰⁺

Name	Description
DEFAULT	Blue text on white background (black background under the dark theme).
HIGHLIGHT	White text on blue background.

Example

// xxx.ets
@Entry
@Component
struct AlertDialogExample {
  build() {
    Column({ space: 5 }) {
      Button('one button dialog')
        .onClick(() => {
          AlertDialog.show(
            {
              title: 'title',
              message: 'text',
              autoCancel: true,
              alignment: DialogAlignment.Bottom,
              offset: { dx: 0, dy: -20 },
              gridCount: 3,
              confirm: {
                value: 'button',
                action: () => {
                  console.info('Button-clicking callback')
                }
              },
              cancel: () => {
                console.info('Closed callbacks')
              }
            }
          )
        })
        .backgroundColor(0x317aff)
      Button('two button dialog')
        .onClick(() => {
          AlertDialog.show(
            {
              title: 'title',
              subtitle: 'subtitle',
              message: 'text',
              autoCancel: true,
              alignment: DialogAlignment.Bottom,
              gridCount: 4,
              offset: { dx: 0, dy: -20 },
              primaryButton: {
                value: 'cancel',
                action: () => {
                  console.info('Callback when the first button is clicked')
                }
              },
              secondaryButton: {
                enabled: true,
                defaultFocus: true,
                style: DialogButtonStyle.HIGHLIGHT,
                value: 'ok',
                action: () => {
                  console.info('Callback when the second button is clicked')
                }
              },
              cancel: () => {
                console.info('Closed callbacks')
              }
            }
          )
        }).backgroundColor(0x317aff)
        Button('three button dialog')
        .onClick(() => {
          AlertDialog.show(
            {
              title: 'title',
              subtitle: 'subtitle',
              message: 'text',
              autoCancel: true,
              alignment: DialogAlignment.Bottom,
              gridCount: 4,
              offset: { dx: 0, dy: -20 },
              buttonDirection: DialogButtonDirection.HORIZONTAL,
              buttons: [
                {
                  value: 'Button',
                  action: () => {
                    console.info('Callback when button1 is clicked')
                  }
                },
                {
                  value: 'Button',
                  action: () => {
                    console.info('Callback when button2 is clicked')
                  }
                },
                {
                  value: 'Button',
                  enabled: true,
                  defaultFocus: true,
                  style: DialogButtonStyle.HIGHLIGHT,
                  action: () => {
                    console.info('Callback when button3 is clicked')
                  }
                },
              ],
              cancel: () => {
                console.info('Closed callbacks')
              }
            }
          )
        }).backgroundColor(0x317aff)
    }.width('100%').margin({ top: 5 })
  }
}

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