Nativescript-Vue Shadow Directive Plugin
This repo is a port to Nativescript-Vue of @JoshDSommer's NativeScript Angular Shadow Directive project. As such, a good portion of the code is inspired by it, but many changes were made to fit into how Vue does Directives.
From the command prompt go to your app's root folder and execute:
npm install nativescript-vue-shadow
How to use it
This is a Vue directive to make your life easier when it comes to using native shadows with Nativescript-Vue.
With this directive, you won't have to worry about all the aspects regarding shadowing on Android and on iOS. On the other hand, if you care about some of the details, you will still be able to provide certain extra attributes and they will superseed the default ones.
However, running this on Android you will require the SDK to be greater or equal than 21 (Android 5.0 Lollipop or later), otherwise shadows will simply not be shown. There should be no problem running this on any version of iOS.
Import the Directive into main.js
Use in your view or component
Simple attribute for
Then in your
script tag you can do something like this where we bind to the object:
There are a couple of platform specific attributes you might want to use to customize your view. Bear in mind some of them clash with CSS styles applied to the same views. When it happens, the default behaviour on Android is the original HTML/CSS styles are lost in favor of the ones provided by this directive. On iOS, on the other hand, HTML/CSS pre-existent styles are regarded, consequently the shadow might not be applied.
The tip is avoid applying things like background color and border radius to the same view you intend to apply this directive (Note: this is now supported).
List of attributes
The table below list and describes all possible attributes as well as show which platform supports each one of them:
|elevation||number | string||both||Determines the elevation of the view from the surface. It does all shadow related calculations. You might want to have a look at this enum of standard material design elevations. FYI, it's calculated in DIPs (or DPs, density independent pixels) on Android, or PTs (points) on iOS.|
|pressedElevation||number | string||Android||Determines the view's elevation when on pressed state.|
||Android||Determines the shape of the view and overrides its format styles.|
|bgcolor||string (#RGB)||Android||Determines view's background color and overrides its previous background. If not set, the previous background is used. NOTE: setting the background to transparent is known to cause issues on Android (the shadow may overlap the background)|
|cornerRadius||number||Android||Determines view's corner radius (CSS border-radius) and overrides its previous style. If this is not set, the view's CSS border-radius are used. FYI, it's calculated in DIPs (or DPs, density independent pixels).|
|translationZ||number||Android||Determines an extra distance (in DIP) to the surface.|
|pressedTranslationZ||number||Android||Determines an extra distance (in DIP) to the surface when the view is in the pressed state.|
|forcePressAnimation||boolean||false||Android||By default, if a view has a StateAnimator, it is overwritten by an animator that raises the View on press. Setting this to true will always define this new animator, essentially making any clickable View work as a button.|
|maskToBounds||boolean||false||iOS||Determines whether the shadow will be limited to the view margins.|
|shadowColor||string (#RGB)||iOS||Determines shadow color. Shadow won't be applied if the view already has background.|
|shadowOffset||number||iOS||Determines the distance in points (only on Y axis) of the shadow. Negative value shows the shadow above the view.|
|shadowOpacity||number||iOS||From 0 to 1. Determines the opacity level of the shadow.|
|shadowRadius||number||iOS||Determines the blurring effect in points of the shadow. The higher the more blurred.|
|useShadowPath||boolean||true||iOS||Determines whether to use shadowPath to render the shadow. Setting this to false negatively impacts performance.|
|rasterize||boolean||false||iOS||Determines whether the view should be rasterized. Activating this will increase memory usage, as rasterized views are stored in memory, but will massively improve performance.|
If you want to be consistent with the Material Design specification but you're sick of trying to memorize which elevation your view should have. We've put together a list of pre-defined elevations:
- SWITCH: 1
- CARD_RESTING: 2
- RAISED_BUTTON_RESTING: 2
- SEARCH_BAR_RESTING: 2
- REFRESH_INDICADOR: 3
- SEARCH_BAR_SCROLLED: 3
- APPBAR: 4
- FAB_RESTING: 6
- SNACKBAR: 6
- BOTTOM_NAVIGATION_BAR: 8
- MENU: 8
- CARD_PICKED_UP: 8,
- RAISED_BUTTON_PRESSED: 8
- SUBMENU_LEVEL1: 9
- SUBMENU_LEVEL2: 10
- SUBMENU_LEVEL3: 11
- SUBMENU_LEVEL4: 12
- SUBMENU_LEVEL5: 13
- FAB_PRESSED: 12
- NAV_DRAWER: 16
- RIGHT_DRAWER: 16
- MODAL_BOTTOM_SHEET: 16
- DIALOG: 24
- PICKER: 24
If you don't even want to check it out every time you have to shadow an element, just import the
Elevation enum and enjoy :)
Override Android default StateListAnimator
Android buttons are split into three categories: floating, raised and flat. Different from labels and other ui elements, each button category has its own state animator. So, when buttons are tapped, Android does affect their elevation (and z translation) in a way that Angular is not notified. At the end of tap animation, buttons get back to resting defaults (i.e. raised button's
elevation at 2dp and
translationZ at 0) overriding the shadow stablished by this plugin.
This plugin replaces the default
StateListAnimator with one that gets back to the values you provide for
Feel free to fill submit a PR if you want the flexibility of defining your own
StateListAnimator. The motivation so far was simply put this plugin to work with buttons without changing the original state once they are clicked.
It's also possible to set this
StateListAnimator to any View, making it behave like a button.
Plugin Development Work Flow
- Clone repository to your machine.
npm installin base directory of project
- Change to Demo directory and then run
- Run and deploy to your device or emulator with
npm run serve:androidor
npm run serve:ios. (use
debug:iosto attach to devtools)
- 0.1.0 Initial implementation