Integrating PullToRefresh into Android Project

Question

I'm using Android Studio 0.4.2 and I want to integrate the ActionBarPullToRefresh feature into my project. But what ever I do, i't wont run... either the apps stops or the compiler stops.

So here are some of the projext files:

Build.gradle

apply plugin: 'android'

android {
    compileSdkVersion 19
    buildToolsVersion "19.0.1"

    defaultConfig {
        minSdkVersion 7
        targetSdkVersion 19
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            runProguard false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.txt'
        }
    }
}

repositories {
    mavenCentral()
}

dependencies {
    compile 'com.github.chrisbanes.actionbarpulltorefresh:library:+'
    compile 'com.android.support:appcompat-v7:+'
}

activity_time_table.xml (its the Main Activity)

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".TimeTable" >


    <!-- We need to wrap the WEbview to enable Pull to refresh -->

    <uk.co.senab.actionbarpulltorefresh.library.PullToRefreshLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/ptr_layout"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <WebView
            android:id="@+id/webViewTimeTable"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_alignParentLeft="true"
            android:layout_alignParentTop="true" />

    </uk.co.senab.actionbarpulltorefresh.library.PullToRefreshLayout>

</RelativeLayout>

ok. so when i Sync the Project with gradl It loads and checks all the dependencies without any errors or whatsoever. But when I try to import the classes which are needed for actionbarpulltorefresh it wont find them or suggests just uk.co.senab.actionbarpulltorefresh.library which won't help.

could you please tell me what I'm doing wrong?