cannot find symbol BR in android data binding

Question

I want to use Android Data Binding and has configured according to the official document.

the error message is : error: cannot find symbol import net.juude.droidviews.BR;

the top level build.gradle file is:

buildscript {     repositories {         jcenter()     }     dependencies {         classpath "com.android.tools.build:gradle:1.3.0-beta2"         classpath 'me.tatarka:gradle-retrolambda:3.0.1'         classpath 'com.neenbedankt.gradle.plugins:android-apt:1.4'         classpath "com.android.databinding:dataBinder:1.0-rc0"     } } allprojects {     repositories {         jcenter()         mavenCentral()     } } 

and the build.gradle file in app module is

apply plugin: 'com.android.application' apply plugin: 'me.tatarka.retrolambda' apply plugin: 'com.neenbedankt.android-apt' apply plugin: 'com.android.databinding'   android {     compileSdkVersion 22     buildToolsVersion "22.0.1"      lintOptions {         abortOnError false     }      defaultConfig {         applicationId "net.juude.droidviews"         minSdkVersion 15         targetSdkVersion 22      }     compileOptions {         sourceCompatibility JavaVersion.VERSION_1_8         targetCompatibility JavaVersion.VERSION_1_8     }      buildTypes {         release {             minifyEnabled false             proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.txt'         }     }     retrolambda {         println("JAVA_HOME: " + System.getenv("JAVA_HOME"))         println("JAVA7_HOME: " + System.getenv("JAVA7_HOME"))         println("JAVA8_HOME: " + System.getenv("JAVA8_HOME"))         javaVersion JavaVersion.VERSION_1_7     } }  dependencies {     compile project(':ptr-lib-debug')     compile project(':library')     compile 'com.android.support:support-v4:22.1.0'     compile 'com.mcxiaoke.volley:library:1.0.+'     compile files('libs/droidmocks.jar')     compile 'com.android.support:support-annotations:22.1.1'     compile 'com.facebook.fresco:fresco:0.5.0'     compile 'com.android.support:recyclerview-v7:22.1.1'     compile 'io.reactivex:rxandroid:0.24.0'     compile 'io.reactivex:rxjava:1.0.6'     compile 'com.google.dagger:dagger:2.0'     apt 'com.google.dagger:dagger-compiler:2.0' } 

the layout file is

<layout xmlns:android="http://schemas.android.com/apk/res/android">     <data>         <variable name="user" type=" net.juude.droidviews.databinding.User" />     </data>     <LinearLayout         android:orientation="vertical" android:layout_width="match_parent"         android:layout_height="match_parent">          <TextView             android:id="@+id/user_name"             android:layout_width="wrap_content"             android:layout_height="wrap_content"             android:text="@{user.mName}"/>          <TextView             android:id="@+id/user_sex"             android:layout_width="wrap_content"             android:layout_height="wrap_content"             android:text="@{user.sex}"/>      </LinearLayout> </layout> 

the fragment is

package net.juude.droidviews.databinding;  import android.databinding.DataBindingUtil; import android.databinding.ViewDataBinding; import android.os.Bundle; import android.support.annotation.Nullable; import android.support.v4.app.Fragment; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup;  import net.juude.droidviews.BR; import net.juude.droidviews.R;  /**  * Created by juude on 15-6-9.  */ public class DataBindingFragment extends Fragment{     @Nullable     @Override     public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {         ViewDataBinding dataBinding = DataBindingUtil.inflate(inflater, R.layout.fragment_data_binding, container, false);         //dataBinding.setVariable(BR.)         User user = new User();         user.setSex("男");         user.setName("Juude");         dataBinding.setVariable(BR.user, user);         return dataBinding.getRoot();     } } 

since I did not get syntax error in Android Studio， I can assume that the Android Studio can recognize the BR class;

But when I compile the project, It tells me that error:cannot find symbol class BR.

so I want to know what should I do to make it generate the right BR.java file?

Answer 1

In case someone still has this problem. I solved this by invalidating the cache in Android Studio. And I'm using Android Studio 2 with API 23

File > Invalidate Caches/Restart

Answer 2

It is a problem caused by android-apt plugin. It ignores the provided dependency that data binding plugin adds.

https://bitbucket.org/hvisser/android-apt/issue/38/android-apt-breaks-brand-new-data-binding#comment-18504545

You can work around it by adding: apt 'com.android.databinding:compiler:1.0-rc0 to your gradle file.