@gennadysx/react-native-linear-gradient
v2.5.7
Published
A <LinearGradient> element for React Native
Downloads
7
Readme
react-native-linear-gradient
A <LinearGradient>
element for React Native
Table of Contents
Installation
Using Yarn
yarn add @gennadysx/react-native-linear-gradient
Using npm
npm install @gennadysx/react-native-linear-gradient --save
With React Native >= 0.60
Run npx pod-install
Linking (for React Native <= 0.59 only)
Note: If you are using react-native version 0.60 or higher you don't need to link react-native-linear-gradient.
Automatic
react-native link @gennadysx/react-native-linear-gradient
Manual
Add the following line to your Podfile:
pod 'BVLinearGradient', :path => '../node_modules/@gennadysx/react-native-linear-gradient'
Run npx pod-install
- Open your project in Xcode
- Right click on
Libraries
and clickAdd Files to "Your Project Name"
. - Look under
node_modules/react-native-linear-gradient/ios
and addBVLinearGradient.xcodeproj
. (Screenshot 1) (Screenshot 2). - Add
libBVLinearGradient.a
toBuild Phases -> Link Binary With Libraries
(Screenshot 1) (Screenshot 2). - Click on
BVLinearGradient.xcodeproj
inLibraries
and go theBuild Settings
tab. - Double click the text to the right of
Header Search Paths
and verify that it has$(SRCROOT)/../react-native/React
- if it isn't, then add it. (Screenshot).
In android/settings.gradle
include ':@gennadysx/react-native-linear-gradient'
project(':@gennadysx/react-native-linear-gradient').projectDir = new File(rootProject.projectDir, '../node_modules/react-native-linear-gradient/android')
In android/app/build.gradle
add:
dependencies {
...
implementation project(':@gennadysx/react-native-linear-gradient')
}
In android/app/src/main/java/com/{YOUR_APP_NAME}/MainActivity.java
for react-native < 0.29,
or android/app/src/main/java/com/{YOUR_APP_NAME}/MainApplication.java
for react-native >= 0.29 add:
// ...
import com.BV.LinearGradient.LinearGradientPackage; // <--- This!
// ...
@Override
protected List<ReactPackage> getPackages() {
return Arrays.<ReactPackage>asList(
new MainReactPackage(),
new LinearGradientPackage() // <---- and This!
);
}
in
windows/MyApp.sln
Add -> Existing Project:node_modules/@gennadysx/react-native-linear-gradient/windows/LinearGradientWPF/LinearGradientWPF.csproj
in
windows/MyApp/MyAppWPF/MyAppWPF.csproj
Add -> Reference -> LinearGradientWPFin
windows/MyApp/MyAppWPF/AppReactPage.cs
add:using LinearGradient;
and
public override List<IReactPackage> Packages => new List<IReactPackage>
{
...
new LinearGradientPackage()
}
Examples
react-native-login is a
legacy component which showcases the use of <LinearGradient>
.
Simple
The following code will produce something like this:
import LinearGradient from '@gennadysx/react-native-linear-gradient';
// Within your render function
<LinearGradient colors={['#4c669f', '#3b5998', '#192f6a']} style={styles.linearGradient}>
<Text style={styles.buttonText}>
Sign in with Facebook
</Text>
</LinearGradient>
// Later on in your styles..
var styles = StyleSheet.create({
linearGradient: {
flex: 1,
paddingLeft: 15,
paddingRight: 15,
borderRadius: 5
},
buttonText: {
fontSize: 18,
fontFamily: 'Gill Sans',
textAlign: 'center',
margin: 10,
color: '#ffffff',
backgroundColor: 'transparent',
},
});
Horizontal gradient
Using the styles from above, set start
and end
like this to make the gradient go from left to right, instead of from top to bottom:
<LinearGradient start={{x: 0, y: 0}} end={{x: 1, y: 0}} colors={['#4c669f', '#3b5998', '#192f6a']} style={styles.linearGradient}>
<Text style={styles.buttonText}>
Sign in with Facebook
</Text>
</LinearGradient>
Text gradient (iOS)
On iOS you can use the MaskedViewIOS
to display text with a gradient. The trick here is to render the text twice; once for the mask, and once to let the gradient have the correct size (hence the opacity: 0
):
<MaskedViewIOS maskElement={<Text style={styles.text} />}>
<LinearGradient colors={['#f00', '#0f0']} start={{ x: 0, y: 0 }} end={{ x: 1, y: 0 }}>
<Text style={[styles.text, { opacity: 0 }]} />
</LinearGradient>
</MaskedViewIOS>
Animated Gradient
Check out Examples/AnimatedGradient (git clone
this project, cd into it, npm install, open in Xcode and run) to see how this is done:
This gif was created using licecap - a great piece of free OSS
Transparent Gradient
The use of transparent
color will most likely not lead to the expected result. transparent
is actually a transparent black color (rgba(0, 0, 0, 0)
). If you need a gradient in which the color is "fading", you need to have the same color with changing alpha channel. Example:
// RGBA
<LinearGradient colors={['rgba(255, 255, 255, 0)', 'rgba(255, 255, 255, 1)']} {...otherGradientProps} />
// Hex
<LinearGradient colors={['#FFFFFF00', '#FFFFFF']} {...otherGradientProps} />
Props
In addition to regular View
props, you can also provide additional props to customize your gradient look:
colors
An array of at least two color values that represent gradient colors. Example: ['red', 'blue']
sets gradient from red to blue.
start
An optional object of the following type: { x: number, y: number }
. Coordinates declare the position that the gradient starts at, as a fraction of the overall size of the gradient, starting from the top left corner. Example: { x: 0.1, y: 0.1 }
means that the gradient will start 10% from the top and 10% from the left.
end
Same as start, but for the end of the gradient.
locations
An optional array of numbers defining the location of each gradient color stop, mapping to the color with the same index in colors
prop. Example: [0.1, 0.75, 1]
means that first color will take 0% - 10%, second color will take 10% - 75% and finally third color will occupy 75% - 100%.
<LinearGradient
start={{x: 0.0, y: 0.25}} end={{x: 0.5, y: 1.0}}
locations={[0,0.5,0.6]}
colors={['#4c669f', '#3b5998', '#192f6a']}
style={styles.linearGradient}>
<Text style={styles.buttonText}>
Sign in with Facebook
</Text>
</LinearGradient>
useAngle / angle / angleCenter
You may want to achieve an angled gradient effect, similar to those in image editors like Photoshop. One issue is that you have to calculate the angle based on the view's size, which only happens asynchronously and will cause unwanted flickr.
In order to do that correctly you can set { useAngle: true, angle: 45, angleCenter: { x: 0.5, y: 0.5} }
, to achieve a gradient with a 45 degrees angle, with its center positioned in the view's exact center.
useAngle
is used to turn on/off angle based calculation (as opposed to start
/end
).
angle
is the angle in degrees.
angleCenter
is the center point of the angle (will control the weight and stretch of the gradient like it does in photoshop.
An example app
You can see this component in action in brentvatne/react-native-login.
Troubleshooting
iOS build fails: library not found, "BVLinearGradient" was not found in the UIManager
- Ensure you have followed the installations steps correctly. (
react-native link
for React Native < 0.60 andnpx pod-install
instead for > 0.60). - Ensure
pod 'BVLinearGradient', :path => '../node_modules/@gennadysx/react-native-linear-gradient'
is present in yourios/Podfile
- Ensure you use
ios/**.xcworkspace
file instead ofios./**.xcodeproj
Invariant Violation: Element type is invalid
Ensure you import the LinearGradient
correctly:
// Like that:
import LinearGradient from '@gennadysx/react-native-linear-gradient';
// Not like that:
import { LinearGradient } from '@gennadysx/react-native-linear-gradient';
Other
Clearing build caches and reinstalling dependencies sometimes solve some issues. Try next steps:
- Reinstalling
node_modules
withrm -rf node_modules && yarn
- Clearing Android Gradle cache with
(cd android && ./gradlew clean)
- Reinstalling iOS CocoaPods with
(cd ios && rm -rf ./ios/Pods/**) && npx pod-install
- Clearing Xcode Build cache (open Xcode and go to Product -> Clean Build Folder)
For other troubleshooting issues, go to React Native Troubleshooting
Other platforms
License
MIT