SearchIndexablesProvider

2. 实现的 provider
   根据索引添加文档可知，该 provider 需要继承自 frameworks/base/core/java/android/provider/SearchIndexablesProvider.java 类，并且添加权限 android.permission.READ_SEARCH_INDEXABLES。过滤 Settings 代码，可以轻易找到：

3. queryXmlResources 实现
以 queryXmlResources 方法为例，该方法用于查询 xml 文件添加的索引数据。

@Override
public Cursor queryXmlResources(String[] projection) {
// 构建 cursor
final MatrixCursor cursor = new MatrixCursor(INDEXABLES_XML_RES_COLUMNS);
final List resources =
getSearchIndexableResourcesFromProvider(getContext());
// 遍历返回的数组，填充 cursor
for (SearchIndexableResource val : resources) {
final Object[] ref = new Object[INDEXABLES_XML_RES_COLUMNS.length];
ref[COLUMN_INDEX_XML_RES_RANK] = val.rank;
ref[COLUMN_INDEX_XML_RES_RESID] = val.xmlResId;
ref[COLUMN_INDEX_XML_RES_CLASS_NAME] = val.className;
ref[COLUMN_INDEX_XML_RES_ICON_RESID] = val.iconResId;
ref[COLUMN_INDEX_XML_RES_INTENT_ACTION] = val.intentAction;
ref[COLUMN_INDEX_XML_RES_INTENT_TARGET_PACKAGE] = val.intentTargetPackage;
ref[COLUMN_INDEX_XML_RES_INTENT_TARGET_CLASS] = null; // intent target class
cursor.addRow(ref);
}

return cursor;

}
可以看到，queryXmlResources 方法返回了一个 MatrixCursor 对象，该对象填充了 getSearchIndexableResourcesFromProvider 方法返回的数组。

private List getSearchIndexableResourcesFromProvider(Context context) {
// 根据 SearchFeatureProvider 对象获取 SearchIndexableResources 对象
// 然后拿到一个 Set 集合
final Collection bundles = FeatureFactory.getFeatureFactory()
.getSearchFeatureProvider().getSearchIndexableResources().getProviderValues();
List resourceList = new ArrayList<>();

for (SearchIndexableData bundle : bundles) {// 通过 SearchIndexableData 获取 SearchIndexProvider 对象Indexable.SearchIndexProvider provider = bundle.getSearchIndexProvider();final List<SearchIndexableResource> resList =// getXmlResourcesToIndex 获取到 SearchIndexableResourceprovider.getXmlResourcesToIndex(context, true);if (resList == null) {continue;}for (SearchIndexableResource item : resList) {item.className = TextUtils.isEmpty(item.className)? bundle.getTargetClass().getName(): item.className;}resourceList.addAll(resList);
}return resourceList;

}
其他查询数据的方法可自行查看源码。

4. SearchIndexableResources 生成
   可查看文件：frameworks/base/packages/SettingsLib/search/processor-src/com/android/settingslib/search/IndexableProcessor.java

/**

• Annotation processor for {@link SearchIndexable} that generates {@link SearchIndexableResources}

• subclasses.
  */
  @SupportedSourceVersion(SourceVersion.RELEASE_17)
  @SupportedOptions(IndexableProcessor.PACKAGE_KEY)
  // 声明该 processor 支持处理的注解类型
  @SupportedAnnotationTypes({“com.android.settingslib.search.SearchIndexable”})
  public class IndexableProcessor extends AbstractProcessor {

  // 定义生成文件的默认包名和类名
  private static final String SETTINGSLIB_SEARCH_PACKAGE = “com.android.settingslib.search”;
  private static final String CLASS_BASE = “SearchIndexableResourcesBase”;
  private static final String CLASS_MOBILE = “SearchIndexableResourcesMobile”;
  private static final String CLASS_TV = “SearchIndexableResourcesTv”;
  private static final String CLASS_WEAR = “SearchIndexableResourcesWear”;
  private static final String CLASS_AUTO = “SearchIndexableResourcesAuto”;
  private static final String CLASS_ARC = “SearchIndexableResourcesArc”;

  static final String PACKAGE_KEY = “com.android.settingslib.search.processor.package”;

  private String mPackage;
  private Filer mFiler;
  private Messager mMessager;
  private boolean mRanOnce;

  @Override
  public boolean process(Set<? extends TypeElement> annotations,
  RoundEnvironment roundEnvironment) {
  if (mRanOnce) {
  // Will get called once per round, but we only want to run on the first one.
  return true;
  }
  mRanOnce = true;

   // 获取 SearchIndexableData 的 全类名final ClassName searchIndexableData =ClassName.get(SETTINGSLIB_SEARCH_PACKAGE, "SearchIndexableData");// 定义字段 mProvidersfinal FieldSpec providers = FieldSpec.builder(ParameterizedTypeName.get(ClassName.get(Set.class),searchIndexableData),"mProviders",Modifier.PRIVATE, Modifier.FINAL).initializer("new $T()", HashSet.class).build();// 定义方法 addIndex，用于向 mProviders 中添加 SearchIndexableDatafinal MethodSpec addIndex = MethodSpec.methodBuilder("addIndex").addModifiers(Modifier.PUBLIC).addParameter(searchIndexableData, "indexClass").addCode("$N.add(indexClass);\n", providers).build();// 定义构造函数final MethodSpec.Builder baseConstructorBuilder = MethodSpec.constructorBuilder().addModifiers(Modifier.PUBLIC);final MethodSpec.Builder mobileConstructorBuilder = MethodSpec.constructorBuilder().addModifiers(Modifier.PUBLIC);final MethodSpec.Builder tvConstructorBuilder = MethodSpec.constructorBuilder().addModifiers(Modifier.PUBLIC);final MethodSpec.Builder wearConstructorBuilder = MethodSpec.constructorBuilder().addModifiers(Modifier.PUBLIC);final MethodSpec.Builder autoConstructorBuilder = MethodSpec.constructorBuilder().addModifiers(Modifier.PUBLIC);final MethodSpec.Builder arcConstructorBuilder = MethodSpec.constructorBuilder().addModifiers(Modifier.PUBLIC);// 遍历带 @SearchIndexable 注解的类，提取for (Element element : roundEnvironment.getElementsAnnotatedWith(SearchIndexable.class)) {if (element.getKind().isClass()) {// 提取类名Name className = element.accept(new SimpleElementVisitor8<Name, Void>() {@Overridepublic Name visitType(TypeElement typeElement, Void aVoid) {return typeElement.getQualifiedName();}}, null);if (className != null) {SearchIndexable searchIndexable = element.getAnnotation(SearchIndexable.class);// 提取 forTarget，指定适用于哪些设备int forTarget = searchIndexable.forTarget();MethodSpec.Builder builder = baseConstructorBuilder;if (forTarget == SearchIndexable.ALL) {builder = baseConstructorBuilder;} else if ((forTarget & SearchIndexable.MOBILE) != 0) {builder = mobileConstructorBuilder;} else if ((forTarget & SearchIndexable.TV) != 0) {builder = tvConstructorBuilder;} else if ((forTarget & SearchIndexable.WEAR) != 0) {builder = wearConstructorBuilder;} else if ((forTarget & SearchIndexable.AUTO) != 0) {builder = autoConstructorBuilder;} else if ((forTarget & SearchIndexable.ARC) != 0) {builder = arcConstructorBuilder;}builder.addCode("$N(new com.android.settingslib.search.SearchIndexableData($L.class, $L"+ ".SEARCH_INDEX_DATA_PROVIDER));\n",addIndex, className, className);} else {throw new IllegalStateException("Null classname from " + element);}}}// 定义方法 getProviderValues，用于返回 mProvidersfinal MethodSpec getProviderValues = MethodSpec.methodBuilder("getProviderValues").addAnnotation(Override.class).addModifiers(Modifier.PUBLIC).returns(ParameterizedTypeName.get(ClassName.get(Collection.class),searchIndexableData)).addCode("return $N;\n", providers).build();// 基类final TypeSpec baseClass = TypeSpec.classBuilder(CLASS_BASE).addModifiers(Modifier.PUBLIC).addSuperinterface(ClassName.get(SETTINGSLIB_SEARCH_PACKAGE, "SearchIndexableResources")).addField(providers).addMethod(baseConstructorBuilder.build()).addMethod(addIndex).addMethod(getProviderValues).build();final JavaFile searchIndexableResourcesBase = JavaFile.builder(mPackage, baseClass).build();// 子类final JavaFile searchIndexableResourcesMobile = JavaFile.builder(mPackage,TypeSpec.classBuilder(CLASS_MOBILE).addModifiers(Modifier.PUBLIC).superclass(ClassName.get(mPackage, baseClass.name)).addMethod(mobileConstructorBuilder.build()).build()).build();...// 写入文件try {searchIndexableResourcesBase.writeTo(mFiler);searchIndexableResourcesMobile.writeTo(mFiler);searchIndexableResourcesTv.writeTo(mFiler);searchIndexableResourcesWear.writeTo(mFiler);searchIndexableResourcesAuto.writeTo(mFiler);searchIndexableResourcesArc.writeTo(mFiler);} catch (IOException e) {mMessager.printMessage(Kind.ERROR, "Error while writing file: " + e);}return true;
  

  }

  // 初始化
  @Override
  public synchronized void init(ProcessingEnvironment processingEnvironment) {
  super.init(processingEnvironment);
  mPackage = processingEnvironment.getOptions()
  .getOrDefault(PACKAGE_KEY, SETTINGSLIB_SEARCH_PACKAGE);
  mFiler = processingEnvironment.getFiler();
  mMessager = processingEnvironment.getMessager();
  }
  }

// 生成的部分文件
// SearchIndexableData
public class SearchIndexableData {
private final Class mTargetClass;
private final Indexable.SearchIndexProvider mSearchIndexProvider;

public SearchIndexableData(Class targetClass, Indexable.SearchIndexProvider provider) {this.mTargetClass = targetClass;this.mSearchIndexProvider = provider;
}public Class getTargetClass() {return this.mTargetClass;
}public Indexable.SearchIndexProvider getSearchIndexProvider() {return this.mSearchIndexProvider;
}

}

// SearchIndexableResourcesMobile
public class SearchIndexableResourcesMobile extends SearchIndexableResourcesBase {
public SearchIndexableResourcesMobile() {
this.addIndex(new SearchIndexableData(DisplaySettings.class, DisplaySettings.SEARCH_INDEX_DATA_PROVIDER));
…
}
}

// SearchIndexableResourcesBase
public class SearchIndexableResourcesBase implements SearchIndexableResources {
private final Set mProviders = new HashSet();

public SearchIndexableResourcesBase() {this.addIndex(new SearchIndexableData(LegalSettings.class, LegalSettings.SEARCH_INDEX_DATA_PROVIDER));...
}public void addIndex(SearchIndexableData indexClass) {this.mProviders.add(indexClass);
}public Collection<SearchIndexableData> getProviderValues() {return this.mProviders;
}

}
5. queryNonIndexableKeys 实现
queryNonIndexableKeys 方法用于查询非索引键。

@Override
public Cursor queryNonIndexableKeys(String[] projection) {
// 构建 MatrixCursor
final MatrixCursor cursor = new MatrixCursor(NON_INDEXABLES_KEYS_COLUMNS);
// 获取非索引键
final List nonIndexableKeys = getNonIndexableKeysFromProvider(getContext());
for (String nik : nonIndexableKeys) {
final Object[] ref = new Object[NON_INDEXABLES_KEYS_COLUMNS.length];
ref[COLUMN_INDEX_NON_INDEXABLE_KEYS_KEY_VALUE] = nik;
cursor.addRow(ref);
}

return cursor;

}
getNonIndexableKeysFromProvider 方法接收 Context 对象，并返回一个 List，其中包含所有非索引键。

private List getNonIndexableKeysFromProvider(Context context) {
// 获取 SearchIndexableData 数据集
final Collection bundles = FeatureFactory.getFeatureFactory()
.getSearchFeatureProvider().getSearchIndexableResources().getProviderValues();

final List<String> nonIndexableKeys = new ArrayList<>();for (SearchIndexableData bundle : bundles) {final long startTime = System.currentTimeMillis();// 获取 Indexable.SearchIndexProvider 对象Indexable.SearchIndexProvider provider = bundle.getSearchIndexProvider();List<String> providerNonIndexableKeys;try {// 各个 provider 实现的 getNonIndexableKeys 方法providerNonIndexableKeys = provider.getNonIndexableKeys(context);} catch (Exception e) {// Catch a generic crash. In the absence of the catch, the background thread will// silently fail anyway, so we aren't losing information by catching the exception.// We crash when the system property exists so that we can test if crashes need to// be fixed.// The gain is that if there is a crash in a specific controller, we don't lose all// non-indexable keys, but we can still find specific crashes in development.if (System.getProperty(SYSPROP_CRASH_ON_ERROR) != null) {throw new RuntimeException(e);}Log.e(TAG, "Error trying to get non-indexable keys from: "+ bundle.getTargetClass().getName(), e);continue;}...nonIndexableKeys.addAll(providerNonIndexableKeys);
}return nonIndexableKeys;

}
6. Indexable.SearchIndexProvider 的实现
设置中实现该接口的是 BaseSearchIndexProvider，具体逻辑：

public class BaseSearchIndexProvider implements Indexable.SearchIndexProvider {
public BaseSearchIndexProvider() {
}

public BaseSearchIndexProvider(int xmlRes) {mXmlRes = xmlRes;
}// 初始化 SearchIndexableResource 并返回，提供了 xmlResId
@Override
public List<SearchIndexableResource> getXmlResourcesToIndex(Context context, boolean enabled) {if (mXmlRes != 0) {final SearchIndexableResource sir = new SearchIndexableResource(context);sir.xmlResId = mXmlRes;return Arrays.asList(sir);}return null;
}
...// 获取非索引键
@Override
@CallSuper
public List<String> getNonIndexableKeys(Context context) {final List<String> nonIndexableKeys = new ArrayList<>();if (!isPageSearchEnabled(context)) {// Entire page should be suppressed, mark all keys from this page as non-indexable.nonIndexableKeys.addAll(getNonIndexableKeysFromXml(context, true /* suppressAllPage */));nonIndexableKeys.addAll(getRawDataToIndex(context, true /* enabled */).stream().map(data -> data.key).collect(Collectors.toList()));return nonIndexableKeys;}nonIndexableKeys.addAll(getNonIndexableKeysFromXml(context, false /* suppressAllPage */));final List<AbstractPreferenceController> controllers = getPreferenceControllers(context);if (controllers != null && !controllers.isEmpty()) {for (AbstractPreferenceController controller : controllers) {if (controller instanceof PreferenceControllerMixin) {((PreferenceControllerMixin) controller).updateNonIndexableKeys(nonIndexableKeys);} else if (controller instanceof BasePreferenceController) {((BasePreferenceController) controller).updateNonIndexableKeys(nonIndexableKeys);} else {Log.e(TAG, controller.getClass().getName()+ " must implement " + PreferenceControllerMixin.class.getName()+ " treating the key non-indexable");nonIndexableKeys.add(controller.getPreferenceKey());}}}return nonIndexableKeys;
}// 获取界面控制器
public List<AbstractPreferenceController> getPreferenceControllers(Context context) {List<AbstractPreferenceController> controllersFromCode = new ArrayList<>();try {controllersFromCode = createPreferenceControllers(context);} catch (Exception e) {Log.w(TAG, "Error initializing controller in fragment: " + this + ", e: " + e);}final List<SearchIndexableResource> res = getXmlResourcesToIndex(context, true);if (res == null || res.isEmpty()) {return controllersFromCode;}List<BasePreferenceController> controllersFromXml = new ArrayList<>();for (SearchIndexableResource sir : res) {controllersFromXml.addAll(PreferenceControllerListHelper.getPreferenceControllersFromXml(context, sir.xmlResId));}controllersFromXml = PreferenceControllerListHelper.filterControllers(controllersFromXml,controllersFromCode);final List<AbstractPreferenceController> allControllers = new ArrayList<>();if (controllersFromCode != null) {allControllers.addAll(controllersFromCode);}allControllers.addAll(controllersFromXml);return allControllers;
}
...private List<String> getKeysFromXml(Context context, @XmlRes int xmlResId,boolean suppressAllPage) {final List<String> keys = new ArrayList<>();try {// 解析 xml 文件final List<Bundle> metadata = PreferenceXmlParserUtils.extractMetadata(context,xmlResId, FLAG_NEED_KEY | FLAG_INCLUDE_PREF_SCREEN | FLAG_NEED_SEARCHABLE);for (Bundle bundle : metadata) {// 判断 suppressAllPage 或 settings:searchable 配置的属性if (suppressAllPage || !bundle.getBoolean(METADATA_SEARCHABLE, true)) {keys.add(bundle.getString(METADATA_KEY));}}} catch (IOException | XmlPullParserException e) {Log.w(TAG, "Error parsing non-indexable from xml " + xmlResId);}return keys;
}

}
如上，可以根据 BaseSearchIndexProvider 的实现，控制某个页面是否索引，或者控制某个页面的某个键是否索引。

每个页面可单独实现对应的方法来控制索引。