Android - elevation style property does not work without backgroundColor.

[niagr]

Issue Description

The elevation style property on Android does not work unless backgroundColor has been specified for the element.

RNPlay example

With backgroundColor applied to instructions element:

Without backgroundColor applied:

Steps to Reproduce / Code Snippets

• Create a View
• Add elevation style property - notice it has no effect
• Add backgroundColor stype property - notice elevation is now applied

Expected Results

Unless I'm missing something elevation should get applied regardless of whether a view has a background color or not.

Additional Information

• React Native version: 0.33
• Platform(s) (iOS, Android, or both?): Android
• Operating System (macOS, Linux, or Windows?): Linux

[leeight]

Checkout this question on Stackoverflow: http://stackoverflow.com/questions/27477371/android-elevation-not-showing-a-shadow

[leeight]

cc @janicduplessis @satya164

How about add a new style property such as outlineProvider (https://developer.android.com/reference/android/view/ViewOutlineProvider.html), just like what we did in Libraries/Components/View/ViewStylePropTypes.js

  /**
   * (Android-only) Sets the elevation of a view, using Android's underlying
   * [elevation API](https://developer.android.com/training/material/shadows-clipping.html#Elevation).
   * This adds a drop shadow to the item and affects z-order for overlapping views.
   * Only supported on Android 5.0+, has no effect on earlier versions.
   * @platform android
   */
  elevation: ReactPropTypes.number,

  outlineProvider: ReactPropTypes.oneOf(['bounds', 'padded_bounds', 'background'])

<View style={{elevation: 10, outlineProvider: 'bounds'}}
  ...
</View>

[leeight]

Looks bad

<View style={{alignItems: 'center', marginTop: 50, elevation: 10, outlineProvider: 'bounds'}}>
  <Text>Hello World</Text>
</View>

[Kishanjvaghela]

@niagr I have implemented CardView for react-native with elevation, that support android(All version) and iOS. Let me know is it help you or not. https://github.com/Kishanjvaghela/react-native-cardview

[hramos]

Hi there! This issue is being closed because it has been inactive for a while. Maybe the issue has been fixed in a recent release, or perhaps it is not affecting a lot of people. Either way, we're automatically closing issues after a period of inactivity. Please do not take it personally!

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