Decompile apk but has bug in xml file

Question

I'm newbie to Android and reverse engineering.I'm now trying to decompile an apk file and import it in Android Studio and run it.I use BBCnews as my apk file and use an online decompile site : www.javadecompilers.com/apk ,I get an zip file and when I import the folder into Android Studio, it comes that there exists some error in the AndroidManifest.xml.

First I change xmlns: in the third line to xmlns:android=,but there still exists many errors.For example,in 11th line,at android:name="bbc.mobile.news.app.ww.BBCNewsWwApp",comes three error:

1. Unresolved package 'app'
2. Unresolved package 'ww'
3. Unresolved class 'BBCNewsWwApp'

and many other similar errors in the file. My file structure is shown in: file structure.There does exist an class 'BBCNewsWwApp',and the defination of this class:

package bbc.mobile.news.app.ww;

import bbc.mobile.app.NewsApplication;
import bbc.mobile.news.ww.receiver.AlarmReceiverWw;

public class BBCNewsWwApp extends NewsApplication {
    private static final String TAG = "BBCNewsUkApp";

    public Class<?> getAlarmReceiverClass() {
        return AlarmReceiverWw.class;
    }
}

I think decompiling should be accurate and I'm very confused why there exist so many errors?

Answer 1

Every APK that are released on Play Store or somewhere else has shrinked it's code and resources using progaurd.

Earlier It was possible to reverse engineer an apk when Android development was done on Eclipse. After Google introduced Android Studio, by default it is obfuscate apk using default progaurd files.

So You will not able to fully reverse engineer an APK.

For more information check obfuscation.