libpng error: Not a PNG file

问题:

I have tried several times to upgrade Android Studio build tools past 1.3.1, but I always end up with this libpng error. I solved one of the errors by completely removing a maven dependency (since the gradle console pointed to exactly where the problem file was), but now I am stuck with the same error and no pointer as to where the problem file is. Am I missing something? Here is the gradle console log:

Executing tasks: [:app:generateDebugSources, :app:generateDebugAndroidTestSources]

Configuration on demand is an incubating feature.
:app:preBuild UP-TO-DATE
:app:preDebugBuild UP-TO-DATE
:app:checkDebugManifest
:app:preReleaseBuild UP-TO-DATE
:app:prepareComAndroidDatabindingAdapters10Rc3Library UP-TO-DATE
:app:prepareComAndroidDatabindingLibrary10Rc3Library UP-TO-DATE
:app:prepareComAndroidSupportAppcompatV72310Library UP-TO-DATE
:app:prepareComAndroidSupportCardviewV72310Library UP-TO-DATE
:app:prepareComAndroidSupportDesign2310Library UP-TO-DATE
:app:prepareComAndroidSupportMediarouterV72220Library UP-TO-DATE
:app:preDebugAndroidTestBuild UP-TO-DATE
:app:prepareComAndroidSupportMultidex101Library UP-TO-DATE
:app:prepareComAndroidSupportPercent2310Library UP-TO-DATE
:app:prepareComAndroidSupportRecyclerviewV72310Library UP-TO-DATE
:app:prepareComAndroidSupportSupportV42310Library UP-TO-DATE
:app:prepareComCrashlyticsSdkAndroidAnswers132Library UP-TO-DATE
:app:prepareComCrashlyticsSdkAndroidBeta113Library UP-TO-DATE
:app:prepareComCrashlyticsSdkAndroidCrashlytics252Library UP-TO-DATE
:app:prepareComCrashlyticsSdkAndroidCrashlyticsCore235Library UP-TO-DATE
:app:prepareComFacebookAndroidFacebookAndroidSdk410Library UP-TO-DATE
:app:prepareComFacebookFrescoDrawee061Library UP-TO-DATE
:app:prepareComFacebookFrescoFbcore061Library UP-TO-DATE
:app:prepareComFacebookFrescoFresco061Library UP-TO-DATE
:app:prepareComFacebookFrescoImagepipeline061Library UP-TO-DATE
:app:prepareComGithubRahatarmanahmedCircularprogressview232Library UP-TO-DATE
:app:prepareComGoogleAndroidExoplayerExoplayerR142Library UP-TO-DATE
:app:prepareComGoogleAndroidGmsPlayServices810Library UP-TO-DATE
:app:prepareComGoogleAndroidGmsPlayServicesAds810Library UP-TO-DATE
:app:prepareComGoogleAndroidGmsPlayServicesAnalytics810Library UP-TO-DATE
:app:prepareComGoogleAndroidGmsPlayServicesAppindexing810Library UP-TO-DATE
:app:prepareComGoogleAndroidGmsPlayServicesAppinvite810Library UP-TO-DATE
:app:prepareComGoogleAndroidGmsPlayServicesAppstate810Library UP-TO-DATE
:app:prepareComGoogleAndroidGmsPlayServicesBase810Library UP-TO-DATE
:app:prepareComGoogleAndroidGmsPlayServicesBasement810Library UP-TO-DATE
:app:prepareComGoogleAndroidGmsPlayServicesCast810Library UP-TO-DATE
:app:prepareComGoogleAndroidGmsPlayServicesDrive810Library UP-TO-DATE
:app:prepareComGoogleAndroidGmsPlayServicesFitness810Library UP-TO-DATE
:app:prepareComGoogleAndroidGmsPlayServicesGames810Library UP-TO-DATE
:app:prepareComGoogleAndroidGmsPlayServicesGcm810Library UP-TO-DATE
:app:prepareComGoogleAndroidGmsPlayServicesIdentity810Library UP-TO-DATE
:app:prepareComGoogleAndroidGmsPlayServicesLocation810Library UP-TO-DATE
:app:prepareComGoogleAndroidGmsPlayServicesMaps810Library UP-TO-DATE
:app:prepareComGoogleAndroidGmsPlayServicesMeasurement810Library UP-TO-DATE
:app:prepareComGoogleAndroidGmsPlayServicesNearby810Library UP-TO-DATE
:app:prepareComGoogleAndroidGmsPlayServicesPanorama810Library UP-TO-DATE
:app:prepareComGoogleAndroidGmsPlayServicesPlus810Library UP-TO-DATE
:app:prepareComGoogleAndroidGmsPlayServicesSafetynet810Library UP-TO-DATE
:app:prepareComGoogleAndroidGmsPlayServicesVision810Library UP-TO-DATE
:app:prepareComGoogleAndroidGmsPlayServicesWallet810Library UP-TO-DATE
:app:prepareComGoogleAndroidGmsPlayServicesWearable810Library UP-TO-DATE
:app:prepareIoFabricSdkAndroidFabric136Library UP-TO-DATE
:app:prepareDebugDependencies
:app:compileDebugAidl UP-TO-DATE
:app:compileDebugRenderscript UP-TO-DATE
:app:generateDebugResValues UP-TO-DATE
:app:generateDebugResources UP-TO-DATE
:app:mergeDebugResources
AAPT err(Facade for 961886319): libpng error: Not a PNG file

 FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:mergeDebugResources'.
> Some file crunching failed, see logs for details

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

BUILD FAILED

Total time: 4.398 secs

Below is my build.gradle (Module:app)

buildscript {
    repositories {
        maven { url 'https://maven.fabric.io/public' }
    }

    dependencies {
        classpath 'io.fabric.tools:gradle:1.+'
    }
}
apply plugin: 'com.android.application'
apply plugin: 'io.fabric'

android {
    compileSdkVersion 23
    buildToolsVersion "23.0.2"

    defaultConfig {
        applicationId "us.revibe.revibe"
        minSdkVersion 16
        targetSdkVersion 23
        versionCode 1
        versionName "1.0"
        multiDexEnabled = true
    }
    buildTypes {
        debug{
            debuggable true
        }
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    dataBinding {
        enabled = true
    }
    dexOptions {
        javaMaxHeapSize "4g"
    }
}

repositories {
//    maven { url 'http://maven.livotovlabs.pro/content/groups/public' }
    maven { url 'https://maven.fabric.io/public' }
}

dependencies {
    compile fileTree(include: ['*.jar'], dir: 'libs')
    compile 'com.android.support:appcompat-v7:23.1.0'
    compile 'com.android.support:cardview-v7:23.1.0'
    compile 'com.android.support:recyclerview-v7:23.1.0'
    compile 'com.android.support:percent:23.1.0'
    compile 'com.android.support:design:23.1.0'
    compile files('libs/core-3.2.1.jar')
    compile files('libs/retrofit-1.9.0.jar')
    compile files('libs/connectionclass-1.0.1.jar')
    compile 'com.squareup.okhttp:okhttp-urlconnection:2.0.0'
    compile 'com.squareup.okhttp:okhttp:2.3.0'
    compile 'com.joanzapata.android:android-iconify:1.0.8'
    compile 'com.github.rahatarmanahmed:circularprogressview:2.3.2'
    compile 'com.facebook.android:facebook-android-sdk:4.1.0'
    compile 'com.facebook.fresco:fresco:0.6.1+'
    compile 'com.google.android.gms:play-services:8.1.0'
    compile 'com.android.support:multidex:1.0.1'
    compile 'com.amazonaws:aws-android-sdk-core:2.+'
    compile 'com.amazonaws:aws-android-sdk-cognito:2.+'
    compile 'com.amazonaws:aws-android-sdk-s3:2.+'
//    compile ('eu.livotov.labs:zxscanlib:2.0.1@aar') {transitive=true}

    compile 'com.google.android.exoplayer:exoplayer:r1.4.2'
    compile('com.crashlytics.sdk.android:crashlytics:2.5.2@aar') {
        transitive = true;
    }
}

And below is my top-level build.gradle

buildscript {
    repositories {
        jcenter()
        mavenCentral()
    }
    dependencies {
        classpath "com.android.tools.build:gradle:1.5.0"

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        jcenter()
    }
}

Reverting back to classpath "com.android.tools.build:gradle:1.3.1" seems to fix the problem, but I would like to begin using all the new features

回答1:

The problem is in your png files. Probably you images were optimized by some png optimization tools. Android studio use AAPT tool to optimize images during building your project. The reason for this problem is that AAPT tool doesn't know that you preprocessed the image.

To get around this in your application you need to specify the option in gradle

  aaptOptions{
    cruncherEnabled = false
}

This is disable AAPT optimization for all of your png files.

Similar question was asked here

回答2:

I took the short way out and simply deleted any unused files I had in my drawables folder. This seems to have solved the problem. In the future I will make sure to crush any PNG's before placing them in the drawables folder, as Tauqir suggested.

回答3:

Actually the reason for this is your some of the so called .png files are not actually PNGs but some other type (mostly I suspect they are JPEGs, but someone else or may be you have renamed them with the .png file extension just to deceive Eclipse. But remember Android Studio is clever than that :D )

To be sure for a check, open one of the PNG image files which might be giving this error in Photoshop like tool (Photoshop is better, because if the file extension is different than it's actual format then it will also give an error. If so to find out what is your image file's actual format is use a webapp like this).

Solution:
After you open your file in Photoshop, save it as PNG. And try building this and mostly this issue might have been gone.

Hope this answer was helpful to somebody out there.
Cheers!