react-native-class-exists

Works currently with:

| iOS | Android | Windows | | --- | ------- | ------- | | Yes | No | No |

Why would I use this?

The situation may arise where you want to incorporate 'new features' that may not run on all your users devices. For instance, a user with iOS 9 will not be able to use SiriKit, whereas a user with iOS 10 will. You can check at run time whether a class exists using this module. You can also use this module to check for device capabilities. For instance, being able to check if a user's device supports ARKit (even if they have iOS 11+, their hardware may not support it).

Getting started

$ npm install react-native-class-exists --save

Mostly automatic installation

$ react-native link react-native-class-exists

Manual installation

iOS

1. In XCode, in the project navigator, right click Libraries ➜ Add Files to [your project's name]
2. Go to node_modules ➜ react-native-class-exists and add RNClassExists.xcodeproj
3. In XCode, in the project navigator, select your project. Add libRNClassExists.a to your project's Build Phases ➜ Link Binary With Libraries
4. Run your project (Cmd+R)<

Android

1. Open up android/app/src/main/java/[...]/MainActivity.java

• Add import com.reactlibrary.RNClassExistsPackage; to the imports at the top of the file
• Add new RNClassExistsPackage() to the list returned by the getPackages() method

2. Append the following lines to android/settings.gradle:

   include ':react-native-class-exists'
   project(':react-native-class-exists').projectDir = new File(rootProject.projectDir, 	'../node_modules/react-native-class-exists/android')

3. Insert the following lines inside the dependencies block in android/app/build.gradle:

     compile project(':react-native-class-exists')

Static Functions:

| function | arguments | notes | | -------- | --------------------| ----- | | exists() | className, callback | If you just want to check if a certain class exists at runtime, this is how you do it. | | classMethodResponse() | className, methodName, responseType, callback | Sometimes you want to be able to do more than just check if a class exists at runtime. Sometimes you need to call a class method and get a return value. This is how you do it. As of now, we only wrote the code to allow you to call static class methods with no arguments. Look below for a list of supported return types |

| Supported Return Types for classMethodResponse (ObjC types) | Javascript form returned | | ----------------------------------------------------------- | ------------------------ | | BOOL | Boolean | | NSNumber | Number | | NSString or String | String | Remember to include the correct returnType for the method you will be calling

Usage Examples

Checking if UIAlertController works (introduced in iOS 8)

import React, { Component } from 'react'
import { Platform } from 'react-native'
import ClassExists from 'react-native-class-exists'

export default class App extends React.Component {
    componentDidMount() {
      if (Platform.OS == 'ios') {
        ClassExists.exists("UIAlertController", exists=>{
            console.log(exists ? "It exists! " : "Does not exist")
        })
      }
    }
}

Checking if the user can make payments (checking for the class isn't enough. So we can check for the class, AND run a method if it exists, as well as get a return value)

if (Platform.OS == 'ios') {
  ClassExists.classMethodResponse("SKPaymentQueue", "canMakePayments", "BOOL", (success, response)=>{
    if (success && response) {
      console.log("User can make payments")
    } else {
      console.log("User cannot make payments")
    }
  })
}

Checking if the user's device will run ARKit (Augmented Reality Kit from iOS 11+)

if (Platform.OS == 'ios') {
  ClassExists.classMethodResponse("ARConfiguration", "isSupported", "BOOL", (success, response)=>{
    if (success) {
      if (response) {
        console.log("User can use ARKit")
      } else {
        console.log("User has software for ARKit, but device doesn't support it. (Probably iOS 11+, but not on a newer device)")
      }
    } else {
      console.log("User cannot use ARKit")
    }
  })
}