After doing ‘expo init’, I entered ‘expo eject’ and separated it.
I made a basic ‘jar’ file to test application to App.js using ‘jar’ file.
The implementation is simple.
CreateAJarFile.class in jar:
class CreateAJarFile {
public static void main(String args[]) {
System.out.println("We got test");
}
}
bild.gradle(app):
dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation files('libs/myJarFile.jar')
After applying Android, I made a module to write modules on ‘Apps.js’.
android/app/src/main/java/com/myjarfile
CreateAJarFile.java:
package com.myjarfile;
import android.widget.Toast;
import com.facebook.react.bridge.NativeModule;
import com.facebook.react.bridge.ReactApplicationContext;
import com.facebook.react.bridge.ReactContext;
import com.facebook.react.bridge.ReactContextBaseJavaModule;
import com.facebook.react.bridge.ReactMethod;
import java.util.Map;
import java.util.HashMap;
public class CreateAJarFile extends ReactContextBaseJavaModule {
private static final String DURATION_SHORT_KEY = "SHORT";
private static final String DURATION_LONG_KEY = "LONG";
public CreateAJarFile(ReactApplicationContext reactContext) {
super(reactContext);
}
@Override
public String getName() {
return "CreateAJar";
}
@Override
public Map<String, Object> getConstants() {
final Map<String, Object> constants = new HashMap<>();
constants.put(DURATION_SHORT_KEY, Toast.LENGTH_SHORT);
constants.put(DURATION_LONG_KEY, Toast.LENGTH_LONG);
return constants;
}
@ReactMethod
public void show() {
System.out.println("We got test");
}
}
CreateAJarFilePackage.java:
package com.myjarfile;
import com.facebook.react.ReactPackage;
import com.facebook.react.bridge.NativeModule;
import com.facebook.react.bridge.ReactApplicationContext;
import com.facebook.react.uimanager.ViewManager;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
public class CreateAJarFilePackage implements ReactPackage {
@Override
public List<ViewManager> createViewManagers(ReactApplicationContext reactContext) {
return Collections.emptyList();
}
@Override
public List<NativeModule> createNativeModules(ReactApplicationContext reactContext) {
List<NativeModule> modules = new ArrayList<>();
modules.add(new CreateAJarFile(reactContext));
return modules;
}
}
CreateAJar.js:
import { NativeModules } from "react-native";
const { CreateAJar } = NativeModules;
export default CreateAJar;
android/app/src/main/java/host/exp/exponent/MainApplication.java
import com.myjarfile.CreateAJarFilePackage;
...
public List<ReactPackage> getPackages() {
return Arrays.<ReactPackage>asList(
// Add your own packages here!
// TODO: add native modules!
// Needed for `react-native link`
// new MainReactPackage()
new CreateAJarFilePackage());
}
I made a module like this, added it, and tested it on App.js.
import CreateAJar from "./android/app/src/main/java/com/myjarfile/CreateAJar";
export default class App extends React.Component {
...
this.jarfunc = this.jarfunc.bind(this);
...
jarfunc() {
CreateAJar.show();
}
...
return (
<View style={styles.container}>
<Text>Test</Text>
<Text>{this.jarfunc}</Text>
</View>
However, both the module and the function could not be read.
How do I apply the module I created to ‘App.js’?