ImageCache | NativeScript

Represents a class that stores handles image download requests and caches the already downloaded images.

Hierarchy

Observable

Index

Constructors

constructor

Properties

Methods

Constructors

constructor

new ImageCache(): ImageCache

Inherited from Observable.constructor

Returns ImageCache

Properties

_isViewBase

_isViewBase: boolean

maxRequests

maxRequests: number

The maximum number of simultaneous download requests. Defaults to 5.

placeholder

placeholder: ImageSource

The image to be used to notify for a pending download request - e.g. loading indicator.

Static downloadErrorEvent

downloadErrorEvent: string

String value used when hooking to download error event.

Static downloadedEvent

downloadedEvent: string

String value used when hooking to downloaded event.

Static propertyChangeEvent

propertyChangeEvent: string

Methods

_createPropertyChangeData

_createPropertyChangeData(propertyName: string, value: any, oldValue?: any): PropertyChangeData

Inherited from Observable._createPropertyChangeData
- Defined in data/observable/index.ts:309
Parameters
- propertyName: string
- value: any
- Optional oldValue: any
Returns PropertyChangeData

Private _downloadCore

_downloadCore(request: DownloadRequest): any

- Defined in ui/image-cache/index.d.ts:104
Parameters
- request: DownloadRequest
Returns any

_emit

_emit(eventNames: string): void

Inherited from Observable._emit
- Defined in data/observable/index.ts:319
Parameters
- eventNames: string
Returns void

Private _onDownloadCompleted

_onDownloadCompleted(key: string, image: any): any

- Defined in ui/image-cache/index.d.ts:108
Parameters
- key: string
- image: any
Returns any

Private _onDownloadError

_onDownloadError(key: string, err: Error): any

- Defined in ui/image-cache/index.d.ts:113
Parameters
- key: string
- err: Error
Returns any

addEventListener

addEventListener(eventNames: string, callback: function, thisArg?: any): void

Inherited from Observable.addEventListener
- Defined in data/observable/index.ts:105
Parameters
- eventNames: string
- callback: function
  - - (data: EventData): void
    - Parameters
      - data: EventData
      Returns void
- Optional thisArg: any
Returns void

clear

clear(): void

- Defined in ui/image-cache/index.d.ts:80
Removes all the previously cached images.

Returns void

disableDownload

disableDownload(): void

- Defined in ui/image-cache/index.d.ts:54
Temporary disables download requests.

Returns void

enableDownload

enableDownload(): void

- Defined in ui/image-cache/index.d.ts:50
Enables previously suspended download requests.

Returns void

enqueue

enqueue(request: DownloadRequest): any

- Defined in ui/image-cache/index.d.ts:63
Adds a new download request at the end of the download queue. This will be the last download to start.

Parameters
- request: DownloadRequest
Returns any

get

get(key: string): any

Overwrites Observable.get
- Defined in ui/image-cache/index.d.ts:68
Gets the image for the specified key. May be undefined if the key is not present in the cache.

Parameters
- key: string
Returns any

hasListeners

hasListeners(eventName: string): boolean

Inherited from Observable.hasListeners
- Defined in data/observable/index.ts:305
Parameters
- eventName: string
Returns boolean

notify

notify<T>(data: T): void

Inherited from Observable.notify
- Defined in data/observable/index.ts:270
Type parameters
- T: NotifyData<T>
Parameters
- data: T
Returns void

notifyPropertyChange

notifyPropertyChange(name: string, value: any, oldValue?: any): void

Inherited from Observable.notifyPropertyChange
- Defined in data/observable/index.ts:301
Parameters
- name: string
- value: any
- Optional oldValue: any
Returns void

off

off(eventNames: string, callback?: any, thisArg?: any): void

Inherited from Observable.off
- Defined in data/observable/index.ts:101
Parameters
- eventNames: string
- Optional callback: any
- Optional thisArg: any
Returns void

on

on(eventNames: string, callback: function, thisArg?: any): any
on(event: "downloaded", callback: function, thisArg?: any): any
on(event: "downloadError", callback: function, thisArg?: any): any

Overwrites Observable.on
- Defined in ui/image-cache/index.d.ts:88
A basic method signature to hook an event listener (shortcut alias to the addEventListener method).

Parameters
- eventNames: string
  
  String corresponding to events (e.g. "propertyChange"). Optionally could be used more events separated by , (e.g. "propertyChange", "change").
- callback: function
  
  Callback function which will be executed when event is raised.
  - - (args: EventData): void
    - Parameters
      - args: EventData
      Returns void
- Optional thisArg: any
  
  An optional parameter which will be used as this context for callback execution.
Returns any
- Defined in ui/image-cache/index.d.ts:93
Raised when the image has been downloaded.

Parameters
- event: "downloaded"
- callback: function
  - - (args: DownloadedData): void
    - Parameters
      - args: DownloadedData
      Returns void
- Optional thisArg: any
Returns any
- Defined in ui/image-cache/index.d.ts:98
Raised if the image download errors.

Parameters
- event: "downloadError"
- callback: function
  - - (args: DownloadError): void
    - Parameters
      - args: DownloadError
      Returns void
- Optional thisArg: any
Returns any

once

once(event: string, callback: function, thisArg?: any): void

Inherited from Observable.once
- Defined in data/observable/index.ts:88
Parameters
- event: string
- callback: function
  - - (data: EventData): void
    - Parameters
      - data: EventData
      Returns void
- Optional thisArg: any
Returns void

push

push(request: DownloadRequest): any

- Defined in ui/image-cache/index.d.ts:59
Adds a new download request at the top of the download queue. This will be the next immediate download to start.

Parameters
- request: DownloadRequest
Returns any

remove

remove(key: string): void

- Defined in ui/image-cache/index.d.ts:76
Removes the cache for the specified key.

Parameters
- key: string
Returns void

removeEventListener

removeEventListener(eventNames: string, callback?: any, thisArg?: any): void

Inherited from Observable.removeEventListener
- Defined in data/observable/index.ts:126
Parameters
- eventNames: string
- Optional callback: any
- Optional thisArg: any
Returns void

set

set(key: string, image: any): void

Overwrites Observable.set
- Defined in ui/image-cache/index.d.ts:72
Sets the image for the specified key.

Parameters
- key: string
- image: any
Returns void

setProperty

setProperty(name: string, value: any): void

Inherited from Observable.setProperty
- Defined in data/observable/index.ts:68
Parameters
- name: string
- value: any
Returns void

Static addEventListener

addEventListener(eventName: string, callback: any, thisArg?: any): void

Inherited from Observable.addEventListener
- Defined in data/observable/index.ts:231
Parameters
- eventName: string
- callback: any
- Optional thisArg: any
Returns void

Static off

off(eventName: string, callback?: any, thisArg?: any): void

Inherited from Observable.off
- Defined in data/observable/index.ts:179
Parameters
- eventName: string
- Optional callback: any
- Optional thisArg: any
Returns void

Static on

on(eventName: string, callback: any, thisArg?: any): void

Inherited from Observable.on
- Defined in data/observable/index.ts:156
Parameters
- eventName: string
- callback: any
- Optional thisArg: any
Returns void

Static once

once(eventName: string, callback: any, thisArg?: any): void

Inherited from Observable.once
- Defined in data/observable/index.ts:160
Parameters
- eventName: string
- callback: any
- Optional thisArg: any
Returns void

Static removeEventListener

removeEventListener(eventName: string, callback?: any, thisArg?: any): void

Inherited from Observable.removeEventListener
- Defined in data/observable/index.ts:183
Parameters
- eventName: string
- Optional callback: any
- Optional thisArg: any
Returns void

Class ImageCache

Hierarchy

Index

Constructors

Properties

Methods

Constructors

constructor

Returns ImageCache

Properties

_isViewBase

maxRequests

placeholder

Static downloadErrorEvent

Static downloadedEvent

Static propertyChangeEvent

Methods

_createPropertyChangeData

Parameters

propertyName: string

value: any

Optional oldValue: any

Returns PropertyChangeData

Private _downloadCore

Parameters

request: DownloadRequest

Returns any

_emit

Parameters

eventNames: string

Returns void

Private _onDownloadCompleted

Parameters

key: string

image: any

Returns any

Private _onDownloadError

Parameters

key: string

err: Error

Returns any

addEventListener

Parameters

eventNames: string

callback: function

Parameters

data: EventData

Returns void

Optional thisArg: any

Returns void

clear

Returns void

disableDownload

Returns void

enableDownload

Returns void

enqueue

Parameters

request: DownloadRequest

Returns any

get

Parameters

key: string

Returns any

hasListeners

Parameters

eventName: string

Returns boolean

notify

Type parameters

T: NotifyData<T>

Parameters

data: T

Returns void

notifyPropertyChange

Parameters

name: string

value: any

Optional oldValue: any

Returns void