React Native Invoke

Invoke any native code directly from Javascript in React Native (without wrapping it first with a native manager). Gives you full access from JS to all native API of iOS and Android.

Why

The story behind this library and why it might be useful:
https://medium.com/@talkol/invoke-any-native-api-directly-from-pure-javascript-in-react-native-1fb6afcdf57d

Install

Both Platforms

• In your project root, npm install react-native-invoke --save
  or add it in your package.json:

  "dependencies": {
    ...
    "react-native-invoke": "^0.2.0"
 }

iOS

• In your project root, npm install react-native-invoke --save

• In Xcode, in Project Navigator (left pane), right-click on the Libraries > Add files to [project name]
  Add ./node_modules/react-native-invoke/ios/RNInvoke.xcodeproj

• In Xcode, in Project Navigator (left pane), click on your project (top) and select the Build Phases tab (right pane)
  In the Link Binary With Libraries section add libRNInvoke.a

• In Xcode, in Project Navigator (left pane), click on your project (top) and select the Build Settings tab (right pane)
  In the Header Search Paths section add $(SRCROOT)/../node_modules/react-native-invoke/ios
  Make sure on the right to mark this new path recursive

Android

• Add react-native-invoke from node_modules to your settings.gradle:

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

• In app/build.gradle add react-native-invoke as a dependency

  dependencies {
      ...
      compile project(':react-native-invoke')
  }

- In `YourApplication.java` register `InvokeReactPackage` in your pacakges:

    ```java
    @Override
    protected List<ReactPackage> getPackages() {
        return Arrays.<ReactPackage>asList(
                new MainReactPackage(),
                ...
                new InvokeReactPackage()
        );
     }
    ```

<br><br>
## Executing calls to native

> Notice that this is regular Javascript code. It has full access to all native API in iOS and there's no RN native manager involved wrapping each individual API call.

```js
import Invoke from 'react-native-invoke';

// execute a single call
const _getContentOffset = Invoke.call(_scrollView, 'contentOffset');
const {x, y} = await Invoke.execute(_getContentOffset);

Invoke.execute returns a promise. The native code doesn't actually execute until Invoke.execute runs.

// execute multiple calls
const _getScrollView = Invoke.call(_scrollParent, 'scrollView');
const _getContentOffset = Invoke.call(_getScrollView, 'contentOffset');
const {x, y} = await Invoke.execute(_getContentOffset);

Only simple serializable objects can pass between native and JS. Since many methods take a complex object as argument, we support making multiple calls in one execution so the result of one call can be passed to the next one without going through JS.

Example invocations

iOS

1. from Objective-C

CGPoint offset = [componentView.scrollView contentOffset];

    to Javascript

const _getScrollView = Invoke.call(_componentView, 'scrollView');
const _getOffset = Invoke.call(_getScrollView, 'contentOffset');
const {x, y} = await Invoke.execute(_getOffset);

###### 2. from Objective-C

CGRect frame = componentView.frame;

    to Javascript

const _getFrame = Invoke.call(_componentView, 'frame');
let {x, y, width, height} = await Invoke.execute(_getFrame);

###### 3. from Objective-C

[componentView setFrame:frame];

    to Javascript

const _setFrame = Invoke.call(_componentView, 'setFrame:', Invoke.IOS.CGRect({x, y, width, height}));
await Invoke.execute(_setFrame);

###### 4. from Objective-C

id textView = [componentView valueForKey:@'_textView'];
CGRect pos = [textView caretRectForPosition:textView.selectedTextRange.start];

    to Javascript

const _getTextView = Invoke.call(_componentView, 'valueForKey:', '_textView');
const _getSelectedTextRange = Invoke.call(_getTextView, 'selectedTextRange');
const _getStartPosition = Invoke.call(_getSelectedTextRange, 'start');
const _getCaretRect = Invoke.call(_getTextView, 'caretRectForPosition:', _getStartPosition);
const {x, y, width, height} = await Invoke.execute(_getCaretRect);

Android

1. from java

reactSwipeRefreshLayout.setRefreshing(false);

    to Javascript

const swipeRefreshLayout = Invoke.React.view(this.refs['refresh']);
const setRefreshing = Invoke.call(swipeRefreshLayout, 'setRefreshing', {type: "Boolean", value: false});
await Invoke.execute(setRefreshing);

2. from java

scrollView.getScrollY()

    to Javascript

const scrollView = Invoke.React.view(this.refs['scroll']);
const getScrollY = Invoke.call(scrollView, 'getScrollY');
const y = await Invoke.execute(getScrollY);

3. from java

textView.getSelectionEnd()

    to Javascript

const textView = Invoke.React.view(this.refs['input']);
const getSelectionEnd = Invoke.call(textView, 'getSelectionEnd');
const selectionEnd = await Invoke.execute(getSelectionEnd);

## Full example project Available [here](example)

iOS

cd example
npm install
react-native run-ios

or open ios/example.xcodeproj to open in xcode.

Android

cd example
npm install
react-native run-android

javascript

• Example of getting the scroll offset of a ScrollView
• Example of getting, changing and setting the frame of RefreshControl
• Example of getting the cursor pos from a TextInput
  
  

API

> Invoke.execute(invocation)

Send the entire invocation to native and execute it. Code runs in native only when we reach this command. Returns a promise with the final return value (make sure it's serializable).

> Invoke.call(target, methodSignature, arg1, arg2, ...)

Prepare a call for later execution.

> Invoke.React.view(componentRef)

Returns (in later execution) the native view backing the React component ref.
Example:

<ScrollView refreshControl={<RefreshControl refreshing={true} ref='myRefreshControl'/>} />
const _componentView = Invoke.React.view(this.refs['myRefreshControl']);

##### > `Invoke.IOS.CGPoint({x, y})`

Returns (in later execution) an iOS point.

> Invoke.IOS.CGRect({x, y, width, height})

Returns (in later execution) an iOS rect.

Notes

• The final return value from native arrives as the promise result of Invoke.execute. It has to be serializable! If you have return values that aren't serializable (like complex objects), you probably need to have several Invoke.calls and pass them between eachother.

• All native code is executed on the main thread.

## License

MIT