Android Studio 0.9.0 - Cannot resolve symbols

Question

After 6h spent trying to fix this by myself, AS is driving me crazy. Everything was fine yesterday and today it can't resolve any of the support libs nor the R symbols.

I tried everthing, including all the suggested fixes I found on StackOverflow. No need to tell me to have a look a this post, I already have and none of the solutions work.

Here's what I tried so far :

• rebuilding / cleaning the project (many times...),
• synchronising the project with Gradle Files,
• check that the support lib is up-to-date in the SDK Manager,
• invalide Caches / restart AS,
• delete the .idea folder and the .iml files of my project, and re-importing it in AS,
• update AS from 0.8.11 to 0.9,
• eventually I ended up uninstalling AS and reinstalling it from scratch

And none of this fixed my issue...

Something really weird is that I also tried to create a whole new project from scratch and to copy/paste all my classes & resources from my corrupted project to this new one. And it worked for a while (~10 min), until it eventually became corrupted the same way, without any apparent reason.

Moreover, no idea if it's relevant, but when I type "ViewPager" in AndroidStudio and hit CTRL-SPACE, it doesn't suggest me the "android.support.v4.view.ViewPager" class. But if I hit CTRL-SPACE 3 times in a row, it DOES suggest it. So I guess that means that it's able to find the support lib somewhere but not to use it?

Here's my build.gradle :

apply plugin: 'com.android.library'

android {
    compileSdkVersion 21
    buildToolsVersion "21.1.0"

    defaultConfig {
        applicationId "com.mathieumaree.library"
        minSdkVersion 15
        targetSdkVersion 21
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            runProguard false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.android.support:appcompat-v7:21.0.0'
    compile 'com.android.support:support-v13:21.0.0'
}

Please, help me, otherwise I'm gonna break my computer soon.

Thanks in advance,

Mathieu

EDIT 1 :

I forgot to mention that this occurs only in one of my projects. The others seem to be fine (at least for now).

EDIT 2 :

I also forgot to mention that my project is composed of an application project plus a library module inside it. So here is the app's build.gradle :

apply plugin: 'com.android.application'

android {
    compileSdkVersion 21
    buildToolsVersion "21.1.0"

    defaultConfig {
        applicationId "com.mathieumaree.materialheaderviewpager"
        minSdkVersion 15
        targetSdkVersion 21
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            runProguard false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile project(':library')
    compile 'com.android.support:support-v13:21.0.0'
    compile 'com.android.support:appcompat-v7:21.0.0'
}

The app Manifest :

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.mathieumaree.materialheaderviewpager" >

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >

        <activity
            android:name="com.mathieumaree.materialheaderviewpager.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

The library manifest :

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.mathieumaree.library">

    <application android:allowBackup="true"
        android:label="@string/app_name"
        android:icon="@drawable/ic_launcher"
        android:theme="@style/AppTheme">

    </application>

</manifest>

The main settings.gradle :

include ':app', ':library'

And the main build.gradle :

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:0.14.0'

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

allprojects {
    repositories {
        jcenter()
    }
}

EDIT 3 :

After trying once more to delete all .idea folers & *.iml files and reloading my project, I noticed that AndroidStudio displayed an error at openning :

Accessing invalid virtual file: file://C:/Users/Mathieu/AppData/Local/Android/android-studio1/sdk/sources/android-21; original:582; found:-: Accessing invalid virtual file: file://C:/Users/Mathieu/AppData/Local/Android/android-studio1/sdk/sources/android-21; original:582; found:-

I'm pretty sure it means it's looking for the SDK to yet another location (AppData/Local...android-21). What I don't understand is :

• there's no SDK folder at this location
• the SDK path indicated in the Project Structure is not this one

Any idea what all this means?

Answer 1

try addind this to buid.gradle

compile 'com.android.support:support-v4:21.0.0

and change build tools version to 20.0.0

Also create a whole new project and see if the same errors are still present in that project.

Try "Tools" -> "Android" -> "Sync Project with Gradle Files"

Answer 2

Well, still not a clue what caused this problem but it would look like I managed to get rid of it, although I had to create a new project from scratch. What I really don't understand is that I've already done this yesterday and it didn't work out.