title: Android Studio: cannot resolve some symbol and method
body: <p>I install the Android Studio and build a new project, but the automatic generated code show lots of "cannot resolve" errors like "cannot resolve symbol app" in the code "import android.support.v7.app.ActionBarActivity;"</p>
  
  <p>The onCreate and setContentView Method cannot be resolved too</p>
  
  <p>My Android Studio version is 0.4.2 , gradle version is 1.9</p>
  
  <p>my build gradle is:</p>
  
  <pre><code>buildscript {
      repositories {
          mavenCentral()
      }
      dependencies {
          classpath 'com.android.tools.build:gradle:0.7.+'
      }
  }
  
  allprojects {
      repositories {
          mavenCentral()
      }
  }
  
  apply plugin: 'android'
  
  android {
      compileSdkVersion 19
      buildToolsVersion "19.0.1"
  
      defaultConfig {
          minSdkVersion 14
          targetSdkVersion 19
       versionCode 1
          versionName "1.0"
      }
      buildTypes {
          release {
              runProguard false
              proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.txt'
          }
      }
  }   
  
  dependencies {
      compile 'com.android.support:appcompat-v7:+'
  }
  </code></pre>