Liferay Screens for Android Troubleshooting and FAQs

Even though Liferay developed Screens for Android with great care, you may still run into some common issues. Here are solutions and tips for solving these issues. You’ll also find answers to common questions about Screens for Android.

General Troubleshooting

Before delving into specific issues, you should first make sure that you have the latest tools installed and know where to get additional help if you need it. You should use the latest Android API level, with the latest version of Android Studio. Although Screens can work with Eclipse ADT or manual Gradle builds, Android Studio is the preferred IDE.

If you’re having trouble using Liferay Screens, it may help to investigate the sample apps developed by Liferay. Both serve as good examples of how to use Screenlets and Views:

When updating an app or Screenlet to a new version of Liferay Screens, make sure to see the Android breaking changes reference article. This article lists changes to Screens that break functionality in prior versions. In most cases, updating your code is relatively straightforward.

If you get stuck at any point, you can post your question on our forum. We’re happy to assist you! If you found a bug or want to suggest an improvement, file a ticket in our Jira. Note that you must log in first to be able to see the project.

Common Issues

This section contains information on common issues that can occur when using Liferay Screens.

Could not find com.liferay.mobile:liferay-screens

This error occurs when Gradle isn’t able to find Liferay Screens or the repository. First, check that the Screens version number you’re trying to use exists in jCenter. You can use this link to see all uploaded versions.

It’s also possible that you’re using an old Gradle plugin that doesn’t use jCenter as the default repository. Screens uses version 1.2.3 and later. You can add jCenter as a new repository by placing this code in your project’s build.gradle file:
```
repositories {
    jcenter()
}
```
Failed to resolve: com.android.support:appcompat-v7

Liferay Screens uses the appcompat library from Google, as do all new Android projects created with the latest Android Studio. The appcompat library uses a custom repository maintained by Google, so it must be updated manually using the Android SDK Manager.

In the Android SDK Manager (located at Tools → Android → SDK Manager in Android Studio), you must install at least version 14 of the Android Support Repository (in the Extras menu), and version 22.1.1 of the Android Support Library.
Duplicate files copied in APK META-INF…

This is a common Android error when using libraries. It occurs because Gradle can’t merge duplicated files such as license or notice files. To prevent this error, add the following code to your build.gradle file:
```
android {
    ...
    packagingOptions {
        exclude 'META-INF/LICENSE'
        exclude 'META-INF/NOTICE'
    }
    ...
}
```
This error may not happen right away, but may only appear later on in the development process. For this reason, it’s recommended that you put the above code in your build.gradle file after creating your project.
Connect failed: ECONNREFUSED (Connection refused), or org.apache.http.conn.HttpHostConnectException

This error occurs when Liferay Screens and the underlying Liferay Mobile SDK can’t connect to the Liferay Portal instance. If you get this error, you should first check the IP address of the server to make sure it’s available. If you’ve overridden the default IP address in server_context.xml, you should check to make sure that you’ve set it to the correct IP. Also, if you’re using the Genymotion emulator, you must use 192.168.56.1 instead of localhost for your app to communicate with a local Liferay instance.
java.io.IOException: open failed: EACCES (Permission denied)

Some Screenlets use temporary files to store information, such as when the User Portrait Screenlet uploads a new portrait, or the DDL Form Screenlet uploads new files to the portal. Your app needs to have the necessary permissions to use a specific Screenlet’s functionality. In this case, add the following line to your AndroidManifest.xml:
```
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
```
If you’re using the device’s camera, you also need to add the following permission:
```
<uses-permission android:name="android.permission.CAMERA"/>
```
No JSON web service action with path …

This error most commonly occurs if you haven’t installed the Liferay Screens Compatibility Plugin. This plugin adds new API calls to Liferay Portal.

FAQs

Do I have to use Android Studio?

No, Liferay Screens also works with Eclipse ADT. You can also compile your project manually with Gradle or another build system. Just make sure you use the compiled aar in your project’s lib folder.

We strongly recommend, however, that you use Android Studio. Android Studio is the official IDE for developing Android apps, and Eclipse ADT is no longer supported. Using Eclipse ADT or compiling manually may cause unexpected issues that are difficult to overcome.
How does Screens handle orientation changes?

Liferay Screens uses an event bus, the EventBus library, to notify activities when the interactor has finished its work.
How can I use a Liferay feature not available in Screens?

There are several ways you can use Liferay features not currently available in Screens. The Liferay Mobile SDK gives you access to all of Liferay’s remote APIs. You can also create a custom Screenlet to support any features not included in Screens by default.
How do I create a new Screenlet?

Screenlet creation is explained in detail here.
How can I customize a Screenlet?

You can customize Screenlets by creating new Views. Fortunately, there’s a tutorial for this!
Does Screens have offline support?

Yes, since Liferay Screens 1.3!