React Native - initialProperties Android

In Android, you can pass initialProps in with the launchOptions as a Bundle.

As is mentioned here in the source code: https://github.com/facebook/react-native/blob/7377fdcc70b25eb023e7c6d1b37eeae2a700cb88/ReactAndroid/src/main/java/com/facebook/react/ReactRootView.java#L325-L334

So you can do something like this:

Bundle initialProps = new Bundle();
initialProps.putString("myKey", "myValue");

mReactRootView.startReactApplication(mReactInstanceManager, "MyAwesomeApp", initialProps);

getlauchOptions has been moved inside ReactActivityDelegate, now I use this code:

public class MainActivity extends ReactActivity {

/**
 * Returns the name of the main component registered from JavaScript.
 * This is used to schedule rendering of the component.
 */
@Override
protected String getMainComponentName() {
    return "myAppName";
}

@Override
protected ReactActivityDelegate createReactActivityDelegate() {
    return new ReactActivityDelegate(this, getMainComponentName()) {
        @Nullable
        @Override
        protected Bundle getLaunchOptions() {
            Bundle initialProps = new Bundle();
            initialProps.putString("SOME_VARIABLE_1", BuildConfig.SOME_VARIABLE_1);
            initialProps.putString("SOME_VARIABLE_2", "some variable 2 value");
            return initialProps;
        }
    };
}

update for react-native > 0.59.0 you need override ReactActivityDelegate in your MainActivity.java

Example

import android.os.Bundle;
import androidx.annotation.Nullable;
import com.facebook.react.ReactActivity;
import com.facebook.react.ReactActivityDelegate;

public class RNTesterActivity extends ReactActivity {
  public static class RNTesterActivityDelegate extends ReactActivityDelegate {
    public RNTesterActivityDelegate(ReactActivity activity, String mainComponentName) {
      super(activity, mainComponentName);
    }

    @Override
    protected Bundle getLaunchOptions() {
       // YOUR PROPS
       Bundle props = new Bundle();
       props.putString("key1", "string");
       props.putInt("key2", 5);
       return props;
    }
  }

  @Override
  protected ReactActivityDelegate createReactActivityDelegate() {
    return new RNTesterActivityDelegate(this, getMainComponentName());
  }

  @Override
  protected String getMainComponentName() {
    return "RNTesterApp";
  }
}