Package has mismatched uid: 10124 on disk, 10134 in settings

Question

I have some problems on Android 2.3.X devices for one of my apps (package name is com.netbiscuits.kicker). However I can not install my APK. I have tried to install it directly from eclipse (debug keystore) with the following message in LogCat:

05-02 09:29:03.671: D/PackageManager(279): Scanning package com.netbiscuits.kicker
05-02 09:29:03.671: E/PackageManager(279): Package com.netbiscuits.kicker has mismatched uid: 10124 on disk, 10134 in settings
05-02 09:29:03.671: I/PackageManager(279): Linking native library dir for /data/app/com.netbiscuits.kicker-1.apk
05-02 09:29:03.681: D/installd(126): DexInv: --- BEGIN '/data/app/com.netbiscuits.kicker-1.apk' ---
05-02 09:29:06.641: D/dalvikvm(2530): creating instr width table
05-02 09:29:07.451: D/dalvikvm(2530): DexOpt: 'Lorg/apache/commons/codec/Decoder;' has an earlier definition; blocking out
05-02 09:29:07.451: D/dalvikvm(2530): DexOpt: 'Lorg/apache/commons/codec/DecoderException;' has an earlier definition; blocking out
05-02 09:29:07.451: D/dalvikvm(2530): DexOpt: 'Lorg/apache/commons/codec/Encoder;' has an earlier definition; blocking out
05-02 09:29:07.451: D/dalvikvm(2530): DexOpt: 'Lorg/apache/commons/codec/EncoderException;' has an earlier definition; blocking out
05-02 09:29:07.451: D/dalvikvm(2530): DexOpt: 'Lorg/apache/commons/codec/StringEncoderComparator;' has an earlier definition; blocking out
05-02 09:29:07.451: D/dalvikvm(2530): DexOpt: 'Lorg/apache/commons/codec/language/DoubleMetaphone$DoubleMetaphoneResult;' has an earlier definition; blocking out
05-02 09:29:07.451: D/dalvikvm(2530): DexOpt: 'Lorg/apache/commons/codec/language/SoundexUtils;' has an earlier definition; blocking out
05-02 09:29:07.451: D/dalvikvm(2530): DexOpt: 'Lorg/apache/commons/codec/net/RFC1522Codec;' has an earlier definition; blocking out
05-02 09:29:07.591: D/dalvikvm(2530): DexOpt: 'Lorg/apache/commons/codec/BinaryDecoder;' has an earlier definition; blocking out
05-02 09:29:07.591: D/dalvikvm(2530): DexOpt: 'Lorg/apache/commons/codec/BinaryEncoder;' has an earlier definition; blocking out
05-02 09:29:07.591: D/dalvikvm(2530): DexOpt: 'Lorg/apache/commons/codec/StringDecoder;' has an earlier definition; blocking out
05-02 09:29:07.591: D/dalvikvm(2530): DexOpt: 'Lorg/apache/commons/codec/StringEncoder;' has an earlier definition; blocking out
05-02 09:29:07.641: D/dalvikvm(2530): DexOpt: 'Lorg/apache/commons/codec/binary/BinaryCodec;' has an earlier definition; blocking out
05-02 09:29:07.641: D/dalvikvm(2530): DexOpt: 'Lorg/apache/commons/codec/binary/Hex;' has an earlier definition; blocking out
05-02 09:29:07.641: D/dalvikvm(2530): DexOpt: 'Lorg/apache/commons/codec/language/DoubleMetaphone;' has an earlier definition; blocking out
05-02 09:29:07.641: D/dalvikvm(2530): DexOpt: 'Lorg/apache/commons/codec/language/Metaphone;' has an earlier definition; blocking out
05-02 09:29:07.641: D/dalvikvm(2530): DexOpt: 'Lorg/apache/commons/codec/language/RefinedSoundex;' has an earlier definition; blocking out
05-02 09:29:07.641: D/dalvikvm(2530): DexOpt: 'Lorg/apache/commons/codec/language/Soundex;' has an earlier definition; blocking out
05-02 09:29:07.641: D/dalvikvm(2530): DexOpt: 'Lorg/apache/commons/codec/net/BCodec;' has an earlier definition; blocking out
05-02 09:29:07.641: D/dalvikvm(2530): DexOpt: 'Lorg/apache/commons/codec/net/QCodec;' has an earlier definition; blocking out
05-02 09:29:07.641: D/dalvikvm(2530): DexOpt: 'Lorg/apache/commons/codec/net/QuotedPrintableCodec;' has an earlier definition; blocking out
05-02 09:29:07.641: D/dalvikvm(2530): DexOpt: 'Lorg/apache/commons/codec/net/URLCodec;' has an earlier definition; blocking out
05-02 09:29:07.671: D/dalvikvm(2530): DexOpt: 'Lorg/apache/commons/codec/binary/Base64;' has an earlier definition; blocking out
05-02 09:29:07.751: D/dalvikvm(2530): DexOpt: couldn't find field Landroid/graphics/BitmapFactory$Options;.inMutable
05-02 09:29:07.971: I/dalvikvm(2530): DexOpt: illegal method access (call Lcom/google/ads/AdRequest;.<init> ()V from Lcom/adtech/mobilesdk/publisher/mediation/admob/AdmobConfiguration;)
05-02 09:29:08.271: D/dalvikvm(2530): DexOpt: couldn't find field Landroid/content/res/Configuration;.smallestScreenWidthDp
05-02 09:29:08.721: I/dalvikvm(2530): DexOpt: not resolving ambiguous class 'Lorg/apache/commons/codec/binary/Hex;'
05-02 09:29:08.801: D/dalvikvm(2530): DexOpt: couldn't find static field
05-02 09:29:08.921: D/dalvikvm(2530): DexOpt: not verifying 'Lorg/apache/commons/codec/Decoder;': multiple definitions
05-02 09:29:08.921: D/dalvikvm(2530): DexOpt: not verifying 'Lorg/apache/commons/codec/DecoderException;': multiple definitions
05-02 09:29:08.921: D/dalvikvm(2530): DexOpt: not verifying 'Lorg/apache/commons/codec/Encoder;': multiple definitions
05-02 09:29:08.921: D/dalvikvm(2530): DexOpt: not verifying 'Lorg/apache/commons/codec/EncoderException;': multiple definitions
05-02 09:29:08.921: D/dalvikvm(2530): DexOpt: not verifying 'Lorg/apache/commons/codec/StringEncoderComparator;': multiple definitions
05-02 09:29:08.921: I/dalvikvm(2530): DexOpt: not resolving ambiguous class 'Lorg/apache/commons/codec/binary/Hex;'
05-02 09:29:08.931: D/dalvikvm(2530): DexOpt: not verifying 'Lorg/apache/commons/codec/language/DoubleMetaphone$DoubleMetaphoneResult;': multiple definitions
05-02 09:29:08.931: D/dalvikvm(2530): DexOpt: not verifying 'Lorg/apache/commons/codec/language/SoundexUtils;': multiple definitions
05-02 09:29:08.941: D/dalvikvm(2530): DexOpt: not verifying 'Lorg/apache/commons/codec/net/RFC1522Codec;': multiple definitions
05-02 09:29:08.941: I/dalvikvm(2530): DexOpt: not resolving ambiguous class 'Lorg/apache/commons/codec/DecoderException;'
05-02 09:29:10.001: D/dalvikvm(2530): DexOpt: not verifying 'Lorg/apache/commons/codec/BinaryDecoder;': multiple definitions
05-02 09:29:10.001: D/dalvikvm(2530): DexOpt: not verifying 'Lorg/apache/commons/codec/BinaryEncoder;': multiple definitions
05-02 09:29:10.001: D/dalvikvm(2530): DexOpt: not verifying 'Lorg/apache/commons/codec/StringDecoder;': multiple definitions
05-02 09:29:10.001: D/dalvikvm(2530): DexOpt: not verifying 'Lorg/apache/commons/codec/StringEncoder;': multiple definitions
05-02 09:29:10.001: I/dalvikvm(2530): DexOpt: not resolving ambiguous class 'Lorg/apache/commons/codec/binary/Base64;'
05-02 09:29:10.001: I/dalvikvm(2530): DexOpt: not resolving ambiguous class 'Lorg/apache/commons/codec/binary/Base64;'
05-02 09:29:10.341: E/dalvikvm(2530): LinearAlloc exceeded capacity (5242880), last=728
05-02 09:29:10.341: E/dalvikvm(2530): VM aborting
05-02 09:29:10.448: I/DEBUG(120): *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
05-02 09:29:10.448: I/DEBUG(120): Build fingerprint: 'SEMC/LT15i_1247-1044/LT15i:2.3.4/4.0.2.A.0.69/uv_v3w:user/release-keys'
05-02 09:29:10.448: I/DEBUG(120): pid: 2530, tid: 2530  >>> /system/bin/dexopt <<<
05-02 09:29:10.448: I/DEBUG(120): signal 11 (SIGSEGV), code 1 (SEGV_MAPERR), fault addr deadd00d
05-02 09:29:10.448: I/DEBUG(120):  r0 fffffe84  r1 deadd00d  r2 00000026  r3 00000000
05-02 09:29:10.448: I/DEBUG(120):  r4 6ca9f600  r5 004ffee4  r6 005001c4  r7 0001a82c
05-02 09:29:10.448: I/DEBUG(120):  r8 000002d8  r9 00000000  10 0000000e  fp 000560a8
05-02 09:29:10.448: I/DEBUG(120):  ip 6ca9f70c  sp 7eea9740  lr 6fd192b9  pc 6ca402c8  cpsr 20000030
05-02 09:29:10.448: I/DEBUG(120):  d0  6472656767756265  d1  746963617061636e
05-02 09:29:10.448: I/DEBUG(120):  d2  0000000600000067  d3  2ab070600000000a
05-02 09:29:10.448: I/DEBUG(120):  d4  2acb49782ab07060  d5  0000000800000002
05-02 09:29:10.448: I/DEBUG(120):  d6  2ab088302ac5d248  d7  0000000c2ac880f0
05-02 09:29:10.448: I/DEBUG(120):  d8  0000020c0db232fe  d9  0000000000000000
05-02 09:29:10.448: I/DEBUG(120):  d10 0000000000000000  d11 0000000000000000
05-02 09:29:10.448: I/DEBUG(120):  d12 0000000000000000  d13 0000000000000000
05-02 09:29:10.448: I/DEBUG(120):  d14 0000000000000000  d15 0000000000000000
05-02 09:29:10.448: I/DEBUG(120):  d16 0000000000000000  d17 0000000000000000
05-02 09:29:10.448: I/DEBUG(120):  d18 0000000000000000  d19 0000000000000000
05-02 09:29:10.448: I/DEBUG(120):  d20 0000000000000000  d21 0000000000000000
05-02 09:29:10.448: I/DEBUG(120):  d22 0000000000000000  d23 0000000000000000
05-02 09:29:10.448: I/DEBUG(120):  d24 0000000000000000  d25 0000000000000000
05-02 09:29:10.448: I/DEBUG(120):  d26 0000000000000000  d27 0000000000000000
05-02 09:29:10.448: I/DEBUG(120):  d28 0000000000000000  d29 0000000000000000
05-02 09:29:10.448: I/DEBUG(120):  d30 0000000000000000  d31 0000000000000000
05-02 09:29:10.448: I/DEBUG(120):  scr 00000000
05-02 09:29:10.471: I/DEBUG(120):          #00  pc 000402c8  /system/lib/libdvm.so
05-02 09:29:10.471: I/DEBUG(120):          #01  pc 0004846e  /system/lib/libdvm.so
05-02 09:29:10.471: I/DEBUG(120):          #02  pc 00064a84  /system/lib/libdvm.so
05-02 09:29:10.471: I/DEBUG(120):          #03  pc 00064e90  /system/lib/libdvm.so
05-02 09:29:10.471: I/DEBUG(120):          #04  pc 000656bc  /system/lib/libdvm.so
05-02 09:29:10.471: I/DEBUG(120):          #05  pc 000658fe  /system/lib/libdvm.so
05-02 09:29:10.481: I/DEBUG(120):          #06  pc 0006513e  /system/lib/libdvm.so
05-02 09:29:10.481: I/DEBUG(120):          #07  pc 0005712c  /system/lib/libdvm.so
05-02 09:29:10.481: I/DEBUG(120):          #08  pc 0005349a  /system/lib/libdvm.so
05-02 09:29:10.481: I/DEBUG(120):          #09  pc 000553c2  /system/lib/libdvm.so
05-02 09:29:10.481: I/DEBUG(120):          #10  pc 000555fe  /system/lib/libdvm.so
05-02 09:29:10.481: I/DEBUG(120):          #11  pc 00056fd0  /system/lib/libdvm.so
05-02 09:29:10.481: I/DEBUG(120):          #12  pc 00057022  /system/lib/libdvm.so
05-02 09:29:10.481: I/DEBUG(120):          #13  pc 00055e4e  /system/lib/libdvm.so
05-02 09:29:10.481: I/DEBUG(120):          #14  pc 00055efc  /system/lib/libdvm.so
05-02 09:29:10.481: I/DEBUG(120):          #15  pc 00056000  /system/lib/libdvm.so
05-02 09:29:10.491: I/DEBUG(120): code around pc:
05-02 09:29:10.491: I/DEBUG(120): 6ca402a8 447a4479 f7d14c0b 2000e982 ea86f7d1
05-02 09:29:10.491: I/DEBUG(120): 6ca402b8 447c4809 6bdb5823 4798b103 22264902
05-02 09:29:10.491: I/DEBUG(120): 6ca402c8 f7d1700a bf00eaee deadd00d 00043947
05-02 09:29:10.491: I/DEBUG(120): 6ca402d8 00045505 0005f342 fffffe84 4b09b40e
05-02 09:29:10.491: I/DEBUG(120): 6ca402e8 4c09b517 aa05447b f852591b 6b5b1b04
05-02 09:29:10.491: I/DEBUG(120): code around lr:
05-02 09:29:10.491: I/DEBUG(120): 6fd19298 4a0e4b0d e92d447b 589c41f0 26004680
05-02 09:29:10.491: I/DEBUG(120): 6fd192a8 686768a5 f9b5e006 b113300c 47c04628
05-02 09:29:10.491: I/DEBUG(120): 6fd192b8 35544306 37fff117 6824d5f5 d1ef2c00
05-02 09:29:10.491: I/DEBUG(120): 6fd192c8 e8bd4630 bf0081f0 00028284 ffffff88
05-02 09:29:10.491: I/DEBUG(120): 6fd192d8 b086b570 f602fb01 9004460c a804a901
05-02 09:29:10.491: I/DEBUG(120): stack:
05-02 09:29:10.491: I/DEBUG(120):     7eea9700  2ab06280  
05-02 09:29:10.491: I/DEBUG(120):     7eea9704  2acc3620  
05-02 09:29:10.491: I/DEBUG(120):     7eea9708  6caa51a0  
05-02 09:29:10.491: I/DEBUG(120):     7eea970c  6ca9f600  
05-02 09:29:10.491: I/DEBUG(120):     7eea9710  6fd4272c  
05-02 09:29:10.491: I/DEBUG(120):     7eea9714  6fd426d8  
05-02 09:29:10.491: I/DEBUG(120):     7eea9718  00000000  
05-02 09:29:10.491: I/DEBUG(120):     7eea971c  6fd192b9  /system/lib/libc.so
05-02 09:29:10.491: I/DEBUG(120):     7eea9720  0005f342  
05-02 09:29:10.491: I/DEBUG(120):     7eea9724  004ffee4  
05-02 09:29:10.491: I/DEBUG(120):     7eea9728  005001c4  
05-02 09:29:10.491: I/DEBUG(120):     7eea972c  0001a82c  
05-02 09:29:10.491: I/DEBUG(120):     7eea9730  000002d8  
05-02 09:29:10.491: I/DEBUG(120):     7eea9734  6fd183b1  /system/lib/libc.so
05-02 09:29:10.491: I/DEBUG(120):     7eea9738  df002777  
05-02 09:29:10.491: I/DEBUG(120):     7eea973c  e3a070ad  
05-02 09:29:10.491: I/DEBUG(120): #00 7eea9740  0001a828  
05-02 09:29:10.491: I/DEBUG(120):     7eea9744  6ca48473  /system/lib/libdvm.so
05-02 09:29:10.491: I/DEBUG(120): #01 7eea9748  000002d8  
05-02 09:29:10.491: I/DEBUG(120):     7eea974c  000002d8  
05-02 09:29:10.491: I/DEBUG(120):     7eea9750  2ce60443  
05-02 09:29:10.491: I/DEBUG(120):     7eea9754  2acc3620  
05-02 09:29:10.491: I/DEBUG(120):     7eea9758  000560a8  
05-02 09:29:10.491: I/DEBUG(120):     7eea975c  2c8a5190  
05-02 09:29:10.491: I/DEBUG(120):     7eea9760  7eea97d8  
05-02 09:29:10.501: I/DEBUG(120):     7eea9764  00000000  
05-02 09:29:10.501: I/DEBUG(120):     7eea9768  0000000e  
05-02 09:29:10.501: I/DEBUG(120):     7eea976c  6ca64a89  /system/lib/libdvm.so
05-02 09:29:10.531: W/installd(126): DexInv: --- END '/data/app/com.netbiscuits.kicker-1.apk' --- status=0x000b, process failed
05-02 09:29:10.531: E/installd(126): dexopt failed on '/data/dalvik-cache/data@[email protected]@classes.dex' res = 11
05-02 09:29:10.541: W/PackageManager(279): Package couldn't be installed in /data/app/com.netbiscuits.kicker-1.apk
05-02 09:29:10.541: I/BootReceiver(279): Copying /data/tombstones/tombstone_07 to DropBox (SYSTEM_TOMBSTONE)
05-02 09:29:10.641: D/dalvikvm(279): GC_EXPLICIT freed 1059K, 34% free 10358K/15623K, external 4874K/6087K, paused 90ms
05-02 09:29:10.671: D/AndroidRuntime(2519): Shutting down VM
05-02 09:29:10.671: D/dalvikvm(2519): GC_CONCURRENT freed 215K, 71% free 304K/1024K, external 0K/0K, paused 0ms+1ms
05-02 09:29:10.671: D/dalvikvm(2519): Debugger has detached; object registry had 1 entries
05-02 09:29:11.411: I/iddd-events(129): Event com.sonyericsson.idd.probe.android.devicemonitor::ApplicationCrash was discarded since it was not active.

I have also tried to install a signed APK directly from Google Play Store. That failed with the error message: "Package file is invalid".

The problem seems to appear only on a handful of android 2.3.x devices and I have absolutely no idea why. I do not use native NDK code, and I have already checked if a library has apache commons included somewhere, but I have found nothing abnormal.

Any suggestion?

Answer 1

The problem was that apache commons version I have specified for this project (maven) was different (newer) from the one that is already integrated in Android 2.x . That has caused this errors:

D/dalvikvm(2530): DexOpt: not verifying 'Lorg/apache/commons/codec/Decoder;': multiple definitions

So I have removed the dependency to apache common and have replaced it with my own implementation. I guess you could also repack the newer apache common classes into your application package or try to play around with scope provided ...

Answer 2

Error Package has mismatched uid: 10124 on disk, 10134 in settings caused by exist folder /data/data/xyz/ where xyz is your app package name.

In this message folder exists and have different owner (10124) from now installed (10134). It is caused by previous unclean install.

For example previous install failed with some errors and do not remove created folders.

Because in folder can be data from other app android can not allow use it. PackageManager try fix it in different ways but if can not do this - it get app different dir and show this message.

Better solution - install app and clean remove it. After that install it again.

Another solution - remove folder /data/data/xyz/ in some ways. May be you need root for this.

Code from PackageManager (comments may be very helpfull):

            // This is a normal package, need to make its data directory.
        dataPath = getDataPathForPackage(pkg.packageName, 0);

        boolean uidError = false;

        if (dataPath.exists()) {
            // XXX should really do this check for each user.
            mOutPermissions[1] = 0;
            FileUtils.getPermissions(dataPath.getPath(), mOutPermissions);

            // If we have mismatched owners for the data path, we have a problem.
            if (mOutPermissions[1] != pkg.applicationInfo.uid) {
                boolean recovered = false;
                if (mOutPermissions[1] == 0) {
                    // The directory somehow became owned by root.  Wow.
                    // This is probably because the system was stopped while
                    // installd was in the middle of messing with its libs
                    // directory.  Ask installd to fix that.
                    int ret = mInstaller.fixUid(pkgName, pkg.applicationInfo.uid,
                            pkg.applicationInfo.uid);
                    if (ret >= 0) {
                        recovered = true;
                        String msg = "Package " + pkg.packageName
                                + " unexpectedly changed to uid 0; recovered to " +
                                + pkg.applicationInfo.uid;
                        reportSettingsProblem(Log.WARN, msg);
                    }
                }
                if (!recovered && ((parseFlags&PackageParser.PARSE_IS_SYSTEM) != 0
                        || (scanMode&SCAN_BOOTING) != 0)) {
                    // If this is a system app, we can at least delete its
                    // current data so the application will still work.
                    int ret = mInstaller.remove(pkgName, 0);
                    if (ret >= 0) {
                        // TODO: Kill the processes first
                        // Remove the data directories for all users
                        sUserManager.removePackageForAllUsers(pkgName);
                        // Old data gone!
                        String prefix = (parseFlags&PackageParser.PARSE_IS_SYSTEM) != 0
                                ? "System package " : "Third party package ";
                        String msg = prefix + pkg.packageName
                                + " has changed from uid: "
                                + mOutPermissions[1] + " to "
                                + pkg.applicationInfo.uid + "; old data erased";
                        reportSettingsProblem(Log.WARN, msg);
                        recovered = true;

                        // And now re-install the app.
                        ret = mInstaller.install(pkgName, pkg.applicationInfo.uid,
                                pkg.applicationInfo.uid);
                        if (ret == -1) {
                            // Ack should not happen!
                            msg = prefix + pkg.packageName
                                    + " could not have data directory re-created after delete.";
                            reportSettingsProblem(Log.WARN, msg);
                            mLastScanError = PackageManager.INSTALL_FAILED_INSUFFICIENT_STORAGE;
                            return null;
                        }
                        // Create data directories for all users
                        sUserManager.installPackageForAllUsers(pkgName,
                                pkg.applicationInfo.uid);
                    }
                    if (!recovered) {
                        mHasSystemUidErrors = true;
                    }
                } else if (!recovered) {
                    // If we allow this install to proceed, we will be broken.
                    // Abort, abort!
                    mLastScanError = PackageManager.INSTALL_FAILED_UID_CHANGED;
                    return null;
                }
                if (!recovered) {
                    pkg.applicationInfo.dataDir = "/mismatched_uid/settings_"
                        + pkg.applicationInfo.uid + "/fs_"
                        + mOutPermissions[1];
                    pkg.applicationInfo.nativeLibraryDir = pkg.applicationInfo.dataDir;
                    String msg = "Package " + pkg.packageName
                            + " has mismatched uid: "
                            + mOutPermissions[1] + " on disk, "
                            + pkg.applicationInfo.uid + " in settings";
                    // writer
                    synchronized (mPackages) {
                        mSettings.mReadMessages.append(msg);
                        mSettings.mReadMessages.append('\n');
                        uidError = true;
                        if (!pkgSetting.uidError) {
                            reportSettingsProblem(Log.ERROR, msg);
                        }
                    }
                }
            }
            pkg.applicationInfo.dataDir = dataPath.getPath(); 

Answer 3

Problem definition

During standard installation, a program called "dexopt" runs to prepare your app for the specific phone it's being installed on. Dexopt uses a fixed-size buffer (called the "LinearAlloc" buffer) to store information about all of the methods in your app. Recent versions of Android use an 8 or 16 MB buffer, but Froyo and Gingerbread (versions 2.2 and 2.3) only have 5 MB. Because older versions of Android have a relatively small buffer, our large number of methods was exceeding the buffer size and causing dexopt to crash.

This is the bug for your issue

Solutions:

1. Proguard: Proguard removes unreferenced classes/methods from your app. Thus your app's dex file size decreases. (I've solved my problem with proguard)
2. Multiple Dex Files: Split your app to multiple dex files. Facebook has a solution for this. Also read this link for managing multiple dex files.

Answer 4

Your problem is that the API you defined in your project settings has to be compatible to properly work with your phone version, which has to match or be supported by the APK build version you are currently using. So, check AndroidManifest.xml and included .jar settings for API compatibility. A good way to go safe and avoid this kind of headache is to publish multiple APKs.

Once you decide to publish multiple APKs, you probably need to create separate Android projects for each APK you intend to publish so that you can appropriately develop them separately. You can do this by simply duplicating your existing project and give it a new name. Alternatively, you might use a build system that can output different resources—such as textures—based on the build configuration.

One way to avoid duplicating large portions of your application code is to use a library project. A library project holds shared code and resources, which you can include in your actual application projects.

_{(source: technotalkative.com)}

When creating multiple projects for the same application, it's a good practice to identify each one with a name that indicates the device restrictions to be placed on the APK, so you can easily identify them. For example, "myAPP08" might be a good name for an application designed for API level 8 and above.

_{(source: se-mc.com)}

To activate multiple APK in the Developer console for Android Market, ensure you have the provide APK versions to match the Android versions you have in mind. Using library project is an extra step that helps you ensure quality and avoid problem of compatibility, when preparing to release your App. The more careful and keen on paying attention to details, the better.

In the end, what matters most is that you APK will be reliable and run smoothly on a larger number of different devices.