How to set canOverrideExistingModule=true in React Native for Android Apps?

Question

I built an android app using React Native, it got built successfully but when I run the app in my Android Virtual Device it shows up a full red screen with the following error:

I have not done native app development ever before neither do I have any knowledge of Java so I have no idea what this error means and how to fix this.

score 114 · Accepted Answer · answered Mar 19 '17 at 09:51

114

The name of the package associated to this error is not AirMapModule but MapsPackage from com.airbnb.android.react.maps.

In your MainApplication.java in directory : android/app/src/main/java/../../ remove any duplicate entry of :

the import package : import com.airbnb.android.react.maps.MapsPackage
the call to the constructor of the module : new MapsPackage() in function getPackages

answered Mar 19 '17 at 09:51

efx

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The first bullet is mentioned everywhere online, but this was the first mention of the second place to look for duplicates. Thank you. – David Sinclair Jun 16 '17 at 21:37
2

This error rise when you are trying to import same package twice in MainApplication.java file – Digvijay Machale Feb 12 '18 at 05:26
1

this works but everytime i link a library it repeat itself – Billy Koswara Mar 06 '18 at 02:37
1

just remove the duplicate imports from MainApplication.java – John May 04 '18 at 19:48
This answer is most assuredly the one you're looking for if you ended up here – Khaldor Mar 10 '19 at 17:38
If you still get the error even after removing duplicates, you may need to remove (comment) `packages.add(new MyReactNativePackage());` lines for the packages that are already auto-linked (no manual installation) – Gürol Canbek Jan 16 '21 at 14:28
Could someone please take a look at my question: https://stackoverflow.com/questions/69201505/react-native-native-module-nativeunimoduleproxy-tried-to-override-nativeunimodu – Say u Sep 16 '21 at 01:51

score 43 · Answer 2 · edited Jun 13 '20 at 06:17

43

Go to file "MainApplication.java" (under .\android\app\src\main\java\com\projectName\)

Make sure that under getPackages() function you don't have duplicate lines (in my case I had "new MapsPackage()" twice).

Fix duplicate imports as well.

edited Jun 13 '20 at 06:17

AmerllicA

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answered Apr 07 '17 at 23:51

Barak Kakoun

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score 21 · Answer 3 · edited Jun 13 '20 at 06:21

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Open the MainApplication.java file by this address: android/app/src/main/java/com/projectName/MainApplication.java and add the following code to MainApplication.java file:

@Override    
public boolean canOverrideExistingModule() {        
  return true;    
}

And everything became correct.

edited Jun 13 '20 at 06:21

AmerllicA

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answered Jul 03 '17 at 07:10

Andrew Fan

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10

What do you mean exactly by native module? library? I'm getting an error "module does not override method from it's superclass" – Lucky_girl Apr 11 '19 at 11:10
7

Can someone please be more specific about this solution? Please tell us what and where ... – T M Aug 20 '19 at 07:38
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Thank you @Andew Fan for actually answering the question – mcabe Oct 09 '19 at 00:08
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@ThembelaniM you can add the override function to the native module's class that extends `ReactContextBaseJavaModule` – mcabe Oct 09 '19 at 00:09
3

Where exactly should one add this snippet? – sudonitin Jul 19 '20 at 11:38
1

Can you check if this goes into the MainApplication.java? Because upon adding this I get an error saying that you can not override a method that is not present in the supertype – Shreyas Shandilya Aug 08 '20 at 10:42
@ShreyasShandilya please look at this answer I just added, https://stackoverflow.com/questions/41846452/how-to-set-canoverrideexistingmodule-true-in-react-native-for-android-apps/63438974#63438974 – Irshad Babar Aug 16 '20 at 16:05

score 15 · Answer 4 · edited Jan 18 '19 at 04:04

15

Go to the MainAplication file.

Remove duplicate package and remove duplicate package in getPackages() method

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

Then after try this command in your terminal :

cd android
./gradlew clean

edited Jan 18 '19 at 04:04

Laura

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answered May 15 '18 at 13:41

HM Hamza Zubair

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score 11 · Answer 5 · answered Aug 25 '19 at 15:12

11

If the version of RN you're using is >= 0.60 then there is the possibility that auto-linking and your manual linking are doing the same thing twice. You have two options:

1- You can revert code changes in getPackages method
2- You can disable auto linking in react-native-config.js file.

answered Aug 25 '19 at 15:12

Mahdi Ghajary

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I was doing exactly same as you mentioned :). Thanks buddy. – Bimal Grg Sep 04 '19 at 09:24
in v0.61.5, this was the answer for me. very un-suspecting – Jim Aug 03 '20 at 23:21

score 11 · Answer 6 · edited Aug 16 '20 at 16:02

The above solutions are all correct, but let me explain a little bit,some of above solutions suggest to override the following method.

@Override    
public boolean canOverrideExistingModule() {        
  return true;    
}

But question is where to override? first of all, you can't override inside MainActivity.java or MainApplication.java file.

You should override it in the class inside some node_modules project folder and that class will be extending from ReactContextBaseJavaModule class.

In my case, it was not getting repeated in imports/adding duplicate packages but it was mainly because of auto linking at the and that was making it to repeat.

I am using react-native-contacts npm package to interact so what I did is that went inside

node_modules\react-native-contacts\android\src\main\java\comrt2zz\reactnativecontacts\ 
ContactsManager.java

and this ContactsManager was extending from the ReactContextBaseJavaModule and I override there and got the problem resolved.

So as general there could be a lot of classes that will be extending from ReactContextBaseJavaModule under different projects inside node_modules, but you need to go for specific a project that will be creating duplication problem and there you should override it.

Ok, thanks a lot, this is exactly what I was looking for. it worked for me, for react-native-contacts — Albin Rdz, Aug 01 '22 at 19:19

score 3 · Answer 7 · answered Jan 12 '20 at 16:11

3

Go to your module (coz of which you are getting this error message) Open the module.. add this code to it...

@Override    
public boolean canOverrideExistingModule() {        
  return true;    
}

answered Jan 12 '20 at 16:11

Rishijay Shrivastava

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which file inside the module? – sudonitin Jul 19 '20 at 11:54
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@globefire look at this answer https://stackoverflow.com/questions/41846452/how-to-set-canoverrideexistingmodule-true-in-react-native-for-android-apps/63438974#63438974 – Irshad Babar Aug 16 '20 at 16:08

score 3 · Answer 8 · edited Mar 18 '22 at 18:42

3

You can remove your package from MainApplication.java

enter image description here

edited Mar 18 '22 at 18:42

Maifee Ul Asad

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answered Mar 03 '22 at 05:34

akriti arora

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Welcome. Please read [How do I write a good answer](https://stackoverflow.com/help/how-to-answer) – Abhishek Dutt Mar 07 '22 at 04:00
its not solution we need this package in app – Prince Hamza Aug 29 '22 at 08:30

score 2 · Answer 9 · answered Jan 25 '17 at 08:51

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You can try check in file MainApplication.java in directory : android\app\src\main\java is have any duplicate package AirMapModule exist or not, and delete 1 if have.

answered Jan 25 '17 at 08:51

Nguyên Hoàng

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There is neither a package nor even a variable by the name AirMapModule in the file MailApplication.java :( – UtkarshPramodGupta Jan 25 '17 at 09:16
what version of react-native you use ? – Nguyên Hoàng Jan 25 '17 at 09:22
react-native-cli: 2.0.1 react-native: 0.36.0 – UtkarshPramodGupta Jan 25 '17 at 09:43
Did you try to check file `MainActivity.java` in the same directory too ? – Nguyên Hoàng Jan 25 '17 at 10:25
Yeah, i just did. Even that doesn't have anything related to AirMapModule. :( – UtkarshPramodGupta Jan 25 '17 at 10:58
Hmm, i usually get this error by using react native link, it duplicate package when it already import in file. Hope you will get an answer soon. – Nguyên Hoàng Jan 25 '17 at 11:21
Yeah i hope so. Thanks anyways. :) – UtkarshPramodGupta Jan 25 '17 at 12:03
@UtkarshPramodGupta look at this answer https://stackoverflow.com/questions/41846452/how-to-set-canoverrideexistingmodule-true-in-react-native-for-android-apps/63438974#63438974 – Irshad Babar Aug 16 '20 at 16:09

score 1 · Answer 10 · answered Nov 08 '19 at 17:50

1

Solution

Goto android/app/src/main/java/YOURPACKAGE/MainApplication.java

Find method getPackages();

Remove this packages.add(new MapsPackage());

Chill Pill! :)

answered Nov 08 '19 at 17:50

Ali Akram

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this is not an answer man (( – Pruteanu Alexandru Nov 25 '21 at 07:28

score 1 · Answer 11 · answered May 03 '20 at 06:03

Add only the modules which are not autolinked at here,

        @Override
        protected List<ReactPackage> getPackages() {
          @SuppressWarnings("UnnecessaryLocalVariable")
          List<ReactPackage> packages = new PackageList(this).getPackages();
          // Packages that cannot be autolinked yet can be added manually here, for 
          // example: packages.add(new MyReactNativePackage());         
          return packages;
        }

If the module is autolinked and added the module here, you will get this error.

score 0 · Answer 12 · answered Jan 22 '19 at 07:22

0

check your MainApplication.java, in particular protected List<ReactPackage> getPackages(); the AirMapModule is probably twice in the list

answered Jan 22 '19 at 07:22

caopeng

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score -1 · Answer 13 · answered Oct 01 '19 at 10:29

-1

if installed library react-navigation you can run via android studio. else remove library react-navigation and just yarn it's will work.

answered Oct 01 '19 at 10:29

Sittisuk Chartrasee

1

score -1 · Answer 14 · answered Jan 11 '21 at 03:15

-1

just remove packages.add(new MapsPackage()); this line MainApplication.java

answered Jan 11 '21 at 03:15

Md. Juyel Rana

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How to set canOverrideExistingModule=true in React Native for Android Apps?

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