support inheritance across modules. Issue #808.

butterknife-compiler/src/main/java/butterknife/compiler/ButterKnifeProcessor.java

@@ -1,5 +1,6 @@
 package butterknife.compiler;
 
+import android.support.annotation.NonNull;
 import butterknife.BindAnim;
 import butterknife.BindArray;
 import butterknife.BindBitmap;
@@ -50,10 +51,10 @@
 import java.util.Arrays;
 import java.util.BitSet;
 import java.util.Deque;
+import java.util.HashSet;
 import java.util.LinkedHashMap;
 import java.util.LinkedHashSet;
 import java.util.List;
-import java.util.HashSet;
 import java.util.Map;
 import java.util.Set;
 import javax.annotation.processing.AbstractProcessor;
@@ -75,6 +76,7 @@
 import javax.lang.model.type.TypeKind;
 import javax.lang.model.type.TypeMirror;
 import javax.lang.model.type.TypeVariable;
+import javax.lang.model.util.ElementFilter;
 import javax.lang.model.util.Elements;
 import javax.lang.model.util.Types;
 import javax.tools.Diagnostic.Kind;
@@ -367,6 +369,12 @@ private Map<TypeElement, BindingSet> findAndParseTargets(RoundEnvironment env) {
         bindingMap.put(type, builder.build());
       } else {
         BindingSet parentBinding = bindingMap.get(parentType);
+
+        // parent binding is null, let's try to find a previouly generated binding
+        if (parentBinding == null && hasViewBinder(parentType)) {
+          parentBinding = createStubBindingSet(parentType);
+        }
+
         if (parentBinding != null) {
           builder.setParent(parentBinding);
           bindingMap.put(type, builder.build());
@@ -380,6 +388,33 @@ private Map<TypeElement, BindingSet> findAndParseTargets(RoundEnvironment env) {
     return bindingMap;
   }
 
+  @NonNull private BindingSet createStubBindingSet(TypeElement parentType) {
+    BindingSet parentBinding;
+    BindingSet.Builder parentBuilder = BindingSet.newBuilder(parentType);
+    if (hasViewBindings(parentType)) {
+      //add a fake field to the parent class so that it will indicate it has a view bindings.
+      //this is required for the subclass to generate a proper view binder
+      parentBuilder.addField(new Id(-1), new FieldViewBinding("", null, false));
+    }
+    parentBinding = parentBuilder.build();
+    return parentBinding;
+  }
+
+  private boolean hasViewBindings(TypeElement parentType) {
+    for (VariableElement fieldElement : ElementFilter.fieldsIn(parentType.getEnclosedElements())) {
+      if (fieldElement.getAnnotation(BindView.class) != null
+              || fieldElement.getAnnotation(BindViews.class) != null) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  private boolean hasViewBinder(TypeElement typeElement) {
+    final String viewBindingClassName = typeElement.getQualifiedName().toString() + "_ViewBinding";
+    return elementUtils.getTypeElement(viewBindingClassName) != null;
+  }
+
   private void logParsingError(Element element, Class<? extends Annotation> annotation,
       Exception e) {
     StringWriter stackTrace = new StringWriter();
@@ -1284,7 +1319,7 @@ private TypeElement findParentType(TypeElement typeElement, Set<TypeElement> par
         return null;
       }
       typeElement = (TypeElement) ((DeclaredType) type).asElement();
-      if (parents.contains(typeElement)) {
+      if (parents.contains(typeElement) || hasViewBinder(typeElement)) {
         return typeElement;
       }
     }

butterknife/build.gradle

@@ -41,6 +41,7 @@ dependencies {
   testImplementation deps.junit
   testImplementation deps.truth
   testImplementation deps.compiletesting
+  testImplementation deps.auto.common
   testImplementation files(getRuntimeJar())
   testImplementation files(org.gradle.internal.jvm.Jvm.current().getToolsJar())
   testImplementation project(':butterknife-compiler')

butterknife/src/test/java/butterknife/InheritanceTest.java

@@ -0,0 +1,62 @@
+package butterknife;
+
+import butterknife.compiler.ButterKnifeProcessor;
+import com.google.common.collect.ImmutableList;
+import com.google.testing.compile.JavaFileObjects;
+import javax.tools.JavaFileObject;
+import javax.tools.StandardLocation;
+import org.junit.Test;
+
+import static com.google.common.truth.Truth.assertAbout;
+import static com.google.testing.compile.JavaSourceSubjectFactory.javaSource;
+import static com.google.testing.compile.JavaSourcesSubjectFactory.javaSources;
+import static java.util.Arrays.asList;
+
+public class InheritanceTest {
+
+  @Test public void bindingViewFinalClassWithBaseClassAlreadyCompiledInDifferentModule() {
+    JavaFileObject testSource = JavaFileObjects.forSourceString("test.Test", ""
+        + "package test;\n"
+        + "import android.view.View;\n"
+        + "import butterknife.BindView;\n"
+        + "import butterknife.precompiled.Base;\n"
+        + "public final class Test extends Base {\n"
+        + "    @BindView(1) View thing;\n"
+        + "}"
+    );
+
+    JavaFileObject bindingTestSource = JavaFileObjects.forSourceString("test/Test_ViewBinding", ""
+        + "package test;\n"
+        + "import android.support.annotation.UiThread;\n"
+        + "import android.view.View;\n"
+        + "import butterknife.internal.Utils;\n"
+        + "import butterknife.precompiled.Base_ViewBinding;\n"
+        + "import java.lang.IllegalStateException;\n"
+        + "import java.lang.Override;\n"
+        + "public final class Test_ViewBinding extends Base_ViewBinding {\n"
+        + "  private Test target;\n"
+        + "  @UiThread\n"
+        + "  public Test_ViewBinding(Test target, View source) {\n"
+        + "    super(target, source);\n"
+        + "    this.target = target;\n"
+        + "    target.thing = Utils.findRequiredView(source, 1, \"field 'thing'\");\n"
+        + "  }\n"
+        + "  @Override\n"
+        + "  public void unbind() {\n"
+        + "    Test target = this.target;\n"
+        + "    if (target == null) throw new IllegalStateException(\"Bindings already cleared.\");\n"
+        + "    this.target = null\n"
+        + "    target.thing = null;\n"
+        + "    super.unbind();\n"
+        + "  }\n"
+        + "}"
+    );
+
+    assertAbout(javaSources()).that(asList(testSource))
+        .withCompilerOptions("-Xlint:-processing")
+        .processedWith(new ButterKnifeProcessor())
+        .compilesWithoutWarnings()
+        .and()
+        .generatesSources(bindingTestSource);
+  }
+}

butterknife/src/test/java/butterknife/precompiled/Base.java

@@ -0,0 +1,8 @@
+package butterknife.precompiled;
+
+import android.view.View;
+import butterknife.BindView;
+
+public class Base {
+    @BindView(1) View thing;
+}

sample/base-library/build.gradle

@@ -0,0 +1,27 @@
+buildscript {
+  repositories {
+    mavenCentral()
+    jcenter()
+  }
+
+  dependencies {
+    classpath "com.jakewharton:butterknife-gradle-plugin:${versions.release}"
+  }
+}
+
+apply plugin: 'com.android.library'
+apply plugin: 'com.jakewharton.butterknife'
+
+android {
+  compileSdkVersion versions.compileSdk
+  buildToolsVersion versions.buildTools
+
+  defaultConfig {
+    minSdkVersion versions.minSdk
+  }
+}
+
+dependencies {
+  compile deps.release.runtime
+  annotationProcessor deps.release.compiler
+}

sample/base-library/src/main/AndroidManifest.xml

@@ -0,0 +1 @@
+<manifest package="com.example.butterknife.baselibrary"/>

sample/base-library/src/main/java/com/example/butterknife/baselibrary/BaseActivity.java

@@ -0,0 +1,11 @@
+package com.example.butterknife.baselibrary;
+
+import android.app.Activity;
+import butterknife.BindString;
+
+public class BaseActivity extends Activity {
+    @BindString(R2.string.app_name) protected String butterKnife;
+    @BindString(R2.string.field_method) protected String fieldMethod;
+    @BindString(R2.string.by_jake_wharton) protected String byJakeWharton;
+    @BindString(R2.string.say_hello) protected String sayHello;
+}

sample/base-library/src/main/res/values/strings.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<resources>
+  <string name="app_name">Butter Knife</string>
+  <string name="field_method">Field and method binding for Android views.</string>
+  <string name="by_jake_wharton">by Jake Wharton</string>
+  <string name="say_hello">Say Hello</string>
+</resources>

sample/library/build.gradle

@@ -24,7 +24,12 @@ android {
 
 dependencies {
   implementation deps.release.runtime
-  annotationProcessor deps.release.compiler
+  implementation project(':sample:base-library')
+
+  //TODO this change is just to demonstrate that the new compiler works well
+  //but should be reversed when the new version is released
+  //annotationProcessor deps.release.compiler
+  annotationProcessor project(':butterknife-compiler')
 
   testImplementation deps.junit
   testImplementation deps.truth

sample/library/src/main/java/com/example/butterknife/library/SimpleActivity.java

@@ -1,7 +1,6 @@
 package com.example.butterknife.library;
 
 import android.annotation.SuppressLint;
-import android.app.Activity;
 import android.os.Bundle;
 import android.support.annotation.NonNull;
 import android.view.View;
@@ -16,11 +15,12 @@
 import butterknife.OnClick;
 import butterknife.OnItemClick;
 import butterknife.OnLongClick;
+import com.example.butterknife.baselibrary.BaseActivity;
 import java.util.List;
 
 import static android.widget.Toast.LENGTH_SHORT;
 
-public class SimpleActivity extends Activity {
+public class SimpleActivity extends BaseActivity {
   private static final ButterKnife.Action<View> ALPHA_FADE = new ButterKnife.Action<View>() {
     @Override public void apply(@NonNull View view, int index) {
       AlphaAnimation alphaAnimation = new AlphaAnimation(0, 1);
@@ -62,10 +62,10 @@ public class SimpleActivity extends Activity {
     ButterKnife.bind(this);
 
     // Contrived code to use the bound fields.
-    title.setText("Butter Knife");
-    subtitle.setText("Field and method binding for Android views.");
-    footer.setText("by Jake Wharton");
-    hello.setText("Say Hello");
+    title.setText(butterKnife);
+    subtitle.setText(fieldMethod);
+    footer.setText(byJakeWharton);
+    hello.setText(sayHello);
 
     adapter = new SimpleAdapter(this);
     listOfThings.setAdapter(adapter);

settings.gradle

@@ -6,6 +6,7 @@ include ':butterknife-lint'
 include ':butterknife-integration-test'
 
 //include ':sample:app'
+//include ':sample:base-library'
 //include ':sample:library'
 
 rootProject.name = 'butterknife-parent'