Android Studio's debugger not stopping at breakpoints within library modules

At the moment I'm developing an Android app that is based on third party code. I started to set breakpoints for understanding the code and soon ran into a problem. Suddenly I couldn't get Android Studio to stop at breakpoints anymore.

I tried to set the breakpoints within onCreate methods, within buttons' OnClickListeners - nothing worked. Now I found out that the only place it works is inside the app module. As the project just has one single activity class in the app module and everything else is provided within library modules in fact I can't debug at all.

I assume there's something wrong in the AndroidManifest.xml or more likely in the build.gradle file. As I just switched from Eclipse to Android Studio, all of this gradle stuff is pretty new to me.

If I hover over a library breakpoint while the app is running, it tells me that "no executable code [is] found at line ...". I assume this is the cause of my problem, but I have no idea about how to fix it.

Are there any "usual suspects" among the entries in build.gradle that could cause my problem?

I already did clean my project and invalidated the cache without success. I even tried the suggestion to add <activity> entries inside the library module for the fragments inside.

Edit: I'm using the most current version of Android Studio (version 1.1.0 from February 18) which should have the similar bug fixed that existed some time ago.

The contents of build.gradle in the app module:

apply plugin: 'com.android.application'

android {
    compileSdkVersion 19
    buildToolsVersion project.ANDROID_BUILD_TOOLS_VERSION

    defaultConfig {
        minSdkVersion Integer.parseInt(project.MIN_SDK)
        targetSdkVersion  Integer.parseInt(project.ANDROID_BUILD_TARGET_SDK_VERSION)
    }

    signingConfigs {
        release {
            keyAlias 'xxx'
            keyPassword 'xxx'
            storeFile file('xxx')
            storePassword 'xxx'
        }
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.txt'
            signingConfig signingConfigs.release
            debuggable false
            jniDebuggable false
            zipAlignEnabled true
        }
        debug {
            minifyEnabled false
            debuggable true
        }
    }

    packagingOptions {
        exclude 'META-INF/DEPENDENCIES'
        exclude 'META-INF/NOTICE'
        exclude 'META-INF/LICENSE'
        exclude 'META-INF/LICENSE.txt'
        exclude 'META-INF/NOTICE.txt'
    }
    productFlavors {
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile project(':firebase_plugin')
}

And the build.gradle of library module:

apply plugin: 'com.android.library'
android {

    compileSdkVersion 19
    buildToolsVersion project.ANDROID_BUILD_TOOLS_VERSION
    defaultConfig {
        minSdkVersion Integer.parseInt(project.MIN_SDK)
        targetSdkVersion Integer.parseInt(project.ANDROID_BUILD_TARGET_SDK_VERSION)
    }

    buildTypes {
        release {
            minifyEnabled true
            zipAlignEnabled true
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.txt'
        }
        debug {
            minifyEnabled false
            debuggable true
        }
    }

    productFlavors {
    }

}

dependencies {
    // Facebook SDK
    compile project(':facebook')

    // Used for StringUtils
    compile files('libs/commons-lang3-3.3.2.jar')
    // Bug tracking
    compile files('libs/bugsense-3.6.1.jar')
    compile fileTree(include: ['*.jar'], dir: 'libs')
    //Google Play Services - For Google Maps
    compile('com.google.android.gms:play-services:5.0.89') {
        exclude group: 'com.google.android', module: 'support-v4'
    }
    // Support Library.
    compile 'com.android.support:support-v13:18.0.+'

    compile('com.android.support:appcompat-v7:19.1.0') {
        exclude group: 'com.google.android', module: 'support-v4'
    }
    // Volley - Networking library from google.
    compile('com.mcxiaoke.volley:library:1.0.0') {
        exclude group: 'com.google.android', module: 'support-v4'
    }
    // Has is own support library in it so need to exclude it so no TOP_LEVEL_EXCEPTION will occur.
    compile('de.greenrobot:greendao:1.3.0') {
        exclude group: 'com.google.android', module: 'support-v4'
    }
    // Firebase
    compile('com.firebase:firebase-simple-login:1.4.2') {
        exclude group: 'com.android.support', module: 'support-v4'
    }
    // Super Toast
    compile('com.github.johnpersano:supertoasts:1.3.4@aar') {
        exclude group: 'com.android.support', module: 'support-v4'
    }
    // Croping images
    compile('com.soundcloud.android:android-crop:0.9.10@aar') {
        exclude group: 'com.android.support', module: 'support-v4'
    }
    compile('com.github.chrisbanes.actionbarpulltorefresh:library:0.9.9') {
        exclude group: 'com.android.support', module: 'support-v4'
    }
}


    packagingOptions {
        exclude 'META-INF/DEPENDENCIES'
        exclude 'META-INF/NOTICE'
        exclude 'META-INF/LICENSE'
        exclude 'META-INF/LICENSE.txt'
        exclude 'META-INF/NOTICE.txt'
    }
    productFlavors {
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile project(':firebase_plugin')
}

As stated in the comments of this issue, setting minifyEnabled false in the debug build is the best practice. By setting this variable in the app module you are disabling the entire proguard build process. It is useful when optimizing the release build, but gives some problems if you are testing and developing.

I kind of solved it, although I don't fully understand it yet. The problem was that ProGuard still was active like @Feantury suggested. I don't know why that was the case as I had specified minifyEnabled false in every build.gradle position I could imagine, but it seems it didn't have any effect.

As I had a crash just a few minutes ago, I saw lines in the stacktrace that looked like so:

java.lang.NullPointerException
        at com.example.MyClass(Unknown Source)
        ...

That made ProGuard the number one suspect for me. After some searching around, I found another SO question that deals with the Unknown Source problem. I tried the suggested solution for debugging with ProGuard enabled and voilà it worked!

Simply add the following lines to proguard-rules.txt:

-renamesourcefileattribute SourceFile    
-keepattributes SourceFile,LineNumberTable

in addition to olik79's answer, I would like to add that , these two lines will make your app hit to breakpoints in fragments. otherwise it may baypass fragments

-keep public class * extends android.support.v4.** {*;}
-keep public class * extends android.app.Fragment

here is my complete edit on proguard-android.txt in sdk\tools\proguard

# The support library contains references to newer platform versions.
# Don't warn about those in case this app is linking against an older
# platform version.  We know about them, and they are safe.
-dontwarn android.support.**

-keep class !android.support.v7.internal.view.menu.**,android.support.** {*;}
-ignorewarnings
-renamesourcefileattribute SourceFile
-keepattributes SourceFile,LineNumberTable

-keep public class * extends android.support.v4.** {*;}
-keep public class * extends android.app.Fragment

I had a problem with trying to debug Kotlin code. The debugger wasn't stoping at any of the breakpoints. It turns out it was an issue with Instant run. I removed all the build directories from my project then I uninstalled the app after that I disabled Instant run.

To disable Instant run go to File > Settings > Build, execution, deployment > Instant run > Uncheck Enable Instant Run

In fact, there's a known issue in Android Studio: Gradle plugin does not propagate debug/release to dependencies. It seems to happen in A Studio 1.4 and 1.5 at least.

When an app is compiled in debug, its modules are in fact compiled in release. That's why proguard may be enabled in debug.

I recommend this answer that worked for me.

I discovered the problem to be that Android Studio was in offline mode. When I changed from offline mode this allowed debugging to work effectively.