title: android package *.databinding does not exist
body: <p>I read more links about this problem, but i dont know whats exactly problem of my project. i set <code>dataBinding</code> as true on <code>build.gradle</code>, below code is my application <code>build.gradle</code> file content</p>
  
  <pre><code>apply plugin: 'com.android.application'
  apply plugin: 'com.neenbedankt.android-apt'
  
  android {
      compileSdkVersion 25
      buildToolsVersion "25.0.2"
      defaultConfig {
          applicationId "com.text.myapp"
          minSdkVersion 15
          targetSdkVersion 25
          versionCode 1
          versionName "1.0"
      }
      buildTypes {
          release {
              minifyEnabled false
              proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
          }
      }
      dataBinding {
          enabled = true
      }
  }
  
  repositories {
      jcenter()
      maven { url "https://jitpack.io" }
      maven { url "https://clojars.org/repo/" }
  }
  
  def support_library = "25.2.0"
  
  dependencies {
      compile fileTree(include: ['*.jar'], dir: 'libs')
      compile "com.android.support:appcompat-v7:${support_library}"
      compile "com.android.support:support-v13:${support_library}"
      compile "com.android.support:cardview-v7:${support_library}"
      compile "com.android.support:recyclerview-v7:${support_library}"
  }
  </code></pre>
  
  <p>My activity:</p>
  
  <pre><code>public class ActivityRegister extends AppCompatActivity {
  
      private ActivityRegisterBinding binding;
  
      @Override
      public void onCreate(@Nullable Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          binding = DataBindingUtil.setContentView(this, R.layout.activity_register);
      }
  }
  </code></pre>
  
  <p>and then, activity layout</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;layout
      xmlns:android="http://schemas.android.com/apk/res/android"&gt;
  
      &lt;data&gt;
          &lt;variable
              name="presenter"
              type="ir.pishguy.cafealachiqpro.Ui.Register.ActivityMain.Model.ActivityRegisterViewModel"/&gt;
      &lt;/data&gt;
  
      &lt;LinearLayout
          android:layout_width="match_parent"
          android:layout_height="match_parent"
          android:layout_margin="-5dp"
          android:orientation="vertical"&gt;
  
          &lt;TextView
              android:id="@+id/default_port"
              android:layout_width="match_parent"
              android:visibility="gone"
              android:layout_height="@dimen/default_textview_height"/&gt;
      &lt;/LinearLayout&gt;
  &lt;/layout&gt;
  </code></pre>
  
  <p>Error on Logcat:</p>
  
  <pre><code>/Users/mahdi/Desktop/Home/Projects/Android/CafeAlachiqPro/app/src/main/java/com/text/myapp/Ui/Register/ActivityMain/Presenter/ActivityRegister.java
  Error:(11, 45) error: package com.text.myapp.databinding does not exist
  Error:(19, 13) error: cannot find symbol class ActivityRegisterBinding
  Warning:The following options were not recognized by any processor: 
  '[android.databinding.artifactType, android.databinding.printEncodedErrors, android.databinding.minApi, android.databinding.isTestVariant, android.databinding.enableDebugLogs, android.databinding.sdkDir, android.databinding.bindingBuildFolder, android.databinding.enableForTests, android.databinding.modulePackage, android.databinding.generationalFileOutDir, android.databinding.xmlOutDir]'
  Error:Execution failed for task ':app:compileDebugJavaWithJavac'.
  &gt; Compilation failed; see the compiler error output for details.
  </code></pre>
  
  <p>My viewModel:</p>
  
  <pre><code>public class ActivityRegisterViewModel extends BaseObservable {
      private String readContactPermission;
      private String getMessages;
  
      public ActivityRegisterViewModel() {
      }
  
      @Bindable
      public String getReadContactPermission() {
          return readContactPermission;
      }
  
      public void setReadContactPermission(String readContactPermission) {
          this.readContactPermission = readContactPermission;
          notifyChange();
      }
  
      public String getGetMessages() {
          return getMessages;
      }
  
      public void setGetMessages(String getMessages) {
          this.getMessages = getMessages;
      }
  }
  </code></pre>