Java tutorial
/* * Copyright (C) 2015 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.android.tools.lint.checks; import static com.android.SdkConstants.ANDROID_URI; import static com.android.SdkConstants.ATTR_NAME; import static com.android.SdkConstants.DOT_XML; import static com.android.SdkConstants.TAG_INTENT_FILTER; import static com.android.SdkConstants.TAG_SERVICE; import static com.android.tools.lint.client.api.JavaParser.TYPE_STRING; import static com.android.xml.AndroidManifest.NODE_ACTION; import static com.android.xml.AndroidManifest.NODE_APPLICATION; import static com.android.xml.AndroidManifest.NODE_METADATA; import com.android.annotations.NonNull; import com.android.annotations.Nullable; import com.android.resources.ResourceFolderType; import com.android.tools.lint.detector.api.Category; import com.android.tools.lint.detector.api.Context; import com.android.tools.lint.detector.api.Detector.JavaPsiScanner; import com.android.tools.lint.detector.api.Detector.XmlScanner; import com.android.tools.lint.detector.api.Implementation; import com.android.tools.lint.detector.api.Issue; import com.android.tools.lint.detector.api.JavaContext; import com.android.tools.lint.detector.api.LintUtils; import com.android.tools.lint.detector.api.Location; import com.android.tools.lint.detector.api.ResourceXmlDetector; import com.android.tools.lint.detector.api.Scope; import com.android.tools.lint.detector.api.Severity; import com.android.tools.lint.detector.api.XmlContext; import com.intellij.psi.JavaRecursiveElementVisitor; import com.intellij.psi.PsiClass; import com.intellij.psi.PsiMethod; import org.w3c.dom.Attr; import org.w3c.dom.Element; import java.util.Arrays; import java.util.Collection; import java.util.EnumSet; import java.util.List; /** * Detector for Android Auto issues. * <p> Uses a {@code <meta-data>} tag with a {@code name="com.google.android.gms.car.application"} * as a trigger for validating Automotive specific issues. */ public class AndroidAutoDetector extends ResourceXmlDetector implements XmlScanner, JavaPsiScanner { @SuppressWarnings("unchecked") public static final Implementation IMPL = new Implementation(AndroidAutoDetector.class, EnumSet.of(Scope.RESOURCE_FILE, Scope.MANIFEST, Scope.JAVA_FILE), Scope.RESOURCE_FILE_SCOPE); /** Invalid attribute for uses tag.*/ public static final Issue INVALID_USES_TAG_ISSUE = Issue.create("InvalidUsesTagAttribute", //$NON-NLS-1$ "Invalid `name` attribute for `uses` element.", "The <uses> element in `<automotiveApp>` should contain a " + "valid value for the `name` attribute.\n" + "Valid values are `media` or `notification`.", Category.CORRECTNESS, 6, Severity.ERROR, IMPL) .addMoreInfo("https://developer.android.com/training/auto/start/index.html#auto-metadata"); /** Missing MediaBrowserService action */ public static final Issue MISSING_MEDIA_BROWSER_SERVICE_ACTION_ISSUE = Issue .create("MissingMediaBrowserServiceIntentFilter", //$NON-NLS-1$ "Missing intent-filter with action `android.media.browse.MediaBrowserService`.", "An Automotive Media App requires an exported service that extends " + "`android.service.media.MediaBrowserService` with an " + "`intent-filter` for the action `android.media.browse.MediaBrowserService` " + "to be able to browse and play media.\n" + "To do this, add\n" + "`<intent-filter>`\n" + " `<action android:name=\"android.media.browse.MediaBrowserService\" />`\n" + "`</intent-filter>`\n to the service that extends " + "`android.service.media.MediaBrowserService`", Category.CORRECTNESS, 6, Severity.ERROR, IMPL) .addMoreInfo("https://developer.android.com/training/auto/audio/index.html#config_manifest"); /** Missing intent-filter for Media Search. */ public static final Issue MISSING_INTENT_FILTER_FOR_MEDIA_SEARCH = Issue .create("MissingIntentFilterForMediaSearch", //$NON-NLS-1$ "Missing intent-filter with action `android.media.action.MEDIA_PLAY_FROM_SEARCH`", "To support voice searches on Android Auto, you should also register an " + "`intent-filter` for the action `android.media.action.MEDIA_PLAY_FROM_SEARCH`" + ".\nTo do this, add\n" + "`<intent-filter>`\n" + " `<action android:name=\"android.media.action.MEDIA_PLAY_FROM_SEARCH\" />`\n" + "`</intent-filter>`\n" + "to your `<activity>` or `<service>`.", Category.CORRECTNESS, 6, Severity.ERROR, IMPL) .addMoreInfo("https://developer.android.com/training/auto/audio/index.html#support_voice"); /** Missing implementation of MediaSession.Callback#onPlayFromSearch*/ public static final Issue MISSING_ON_PLAY_FROM_SEARCH = Issue.create("MissingOnPlayFromSearch", //$NON-NLS-1$ "Missing `onPlayFromSearch`.", "To support voice searches on Android Auto, in addition to adding an " + "`intent-filter` for the action `onPlayFromSearch`," + " you also need to override and implement " + "`onPlayFromSearch(String query, Bundle bundle)`", Category.CORRECTNESS, 6, Severity.ERROR, IMPL) .addMoreInfo("https://developer.android.com/training/auto/audio/index.html#support_voice"); private static final String CAR_APPLICATION_METADATA_NAME = "com.google.android.gms.car.application"; //$NON-NLS-1$ private static final String VAL_NAME_MEDIA = "media"; //$NON-NLS-1$ private static final String VAL_NAME_NOTIFICATION = "notification"; //$NON-NLS-1$ private static final String TAG_AUTOMOTIVE_APP = "automotiveApp"; //$NON-NLS-1$ private static final String ATTR_RESOURCE = "resource"; //$NON-NLS-1$ private static final String TAG_USES = "uses"; //$NON-NLS-1$ private static final String ACTION_MEDIA_BROWSER_SERVICE = "android.media.browse.MediaBrowserService"; //$NON-NLS-1$ private static final String ACTION_MEDIA_PLAY_FROM_SEARCH = "android.media.action.MEDIA_PLAY_FROM_SEARCH"; //$NON-NLS-1$ private static final String CLASS_MEDIA_SESSION_CALLBACK = "android.media.session.MediaSession.Callback"; //$NON-NLS-1$ private static final String CLASS_V4MEDIA_SESSION_COMPAT_CALLBACK = "android.support.v4.media.session.MediaSessionCompat.Callback"; //$NON-NLS-1$ private static final String METHOD_MEDIA_SESSION_PLAY_FROM_SEARCH = "onPlayFromSearch"; //$NON-NLS-1$ private static final String BUNDLE_ARG = "android.os.Bundle"; //$NON-NLS-1$ /** * Indicates whether we identified that the current app is an automotive app and * that we should validate all the automotive specific issues. */ private boolean mDoAutomotiveAppCheck; /** Indicates that a {@link #ACTION_MEDIA_BROWSER_SERVICE} intent-filter action was found. */ private boolean mMediaIntentFilterFound; /** Indicates that a {@link #ACTION_MEDIA_PLAY_FROM_SEARCH} intent-filter action was found. */ private boolean mMediaSearchIntentFilterFound; /** The resource file name deduced by the meta-data resource value */ private String mAutomotiveResourceFileName; /** Indicates whether this app is an automotive Media App. */ private boolean mIsAutomotiveMediaApp; /** {@link Location.Handle} to the application element */ private Location.Handle mMainApplicationHandle; /** Constructs a new {@link AndroidAutoDetector} check */ public AndroidAutoDetector() { } @Override public boolean appliesTo(@NonNull ResourceFolderType folderType) { // We only need to check the meta data resource file in res/xml if any. return folderType == ResourceFolderType.XML; } @Override public Collection<String> getApplicableElements() { return Arrays.asList(TAG_AUTOMOTIVE_APP, // Root element of a declared automotive descriptor. NODE_METADATA, // meta-data from AndroidManifest.xml TAG_SERVICE, // service from AndroidManifest.xml TAG_INTENT_FILTER, // Any declared intent-filter from AndroidManifest.xml NODE_APPLICATION // Used for storing the application element/location. ); } @Override public void beforeCheckProject(@NonNull Context context) { mIsAutomotiveMediaApp = false; mAutomotiveResourceFileName = null; mMediaIntentFilterFound = false; mMediaSearchIntentFilterFound = false; } @Override public void visitElement(@NonNull XmlContext context, @NonNull Element element) { String tagName = element.getTagName(); if (NODE_METADATA.equals(tagName) && !mDoAutomotiveAppCheck) { checkAutoMetadataTag(element); } else if (TAG_AUTOMOTIVE_APP.equals(tagName)) { checkAutomotiveAppElement(context, element); } else if (NODE_APPLICATION.equals(tagName)) { // Disable reporting the error if the Issue was suppressed at // the application level. if (context.getMainProject() == context.getProject() && !context.getProject().isLibrary()) { mMainApplicationHandle = context.createLocationHandle(element); mMainApplicationHandle.setClientData(element); } } else if (TAG_SERVICE.equals(tagName)) { checkServiceForBrowserServiceIntentFilter(element); } else if (TAG_INTENT_FILTER.equals(tagName)) { checkForMediaSearchIntentFilter(element); } } private void checkAutoMetadataTag(Element element) { String name = element.getAttributeNS(ANDROID_URI, ATTR_NAME); if (CAR_APPLICATION_METADATA_NAME.equals(name)) { String autoFileName = element.getAttributeNS(ANDROID_URI, ATTR_RESOURCE); if (autoFileName != null && autoFileName.startsWith("@xml/")) { //$NON-NLS-1$ // Store the fact that we need to check all the auto issues. mDoAutomotiveAppCheck = true; mAutomotiveResourceFileName = autoFileName.substring("@xml/".length()) + DOT_XML; //$NON-NLS-1$ } } } private void checkAutomotiveAppElement(XmlContext context, Element element) { // Indicates whether the current file matches the resource that was registered // in AndroidManifest.xml. boolean isMetadataResource = mAutomotiveResourceFileName != null && mAutomotiveResourceFileName.equals(context.file.getName()); for (Element child : LintUtils.getChildren(element)) { if (TAG_USES.equals(child.getTagName())) { String attrValue = child.getAttribute(ATTR_NAME); if (VAL_NAME_MEDIA.equals(attrValue)) { mIsAutomotiveMediaApp |= isMetadataResource; } else if (!VAL_NAME_NOTIFICATION.equals(attrValue) && context.isEnabled(INVALID_USES_TAG_ISSUE)) { // Error invalid value for attribute. Attr node = child.getAttributeNode(ATTR_NAME); if (node == null) { // no name specified continue; } context.report(INVALID_USES_TAG_ISSUE, node, context.getLocation(node), "Expecting one of `" + VAL_NAME_MEDIA + "` or `" + VAL_NAME_NOTIFICATION + "` for the name " + "attribute in " + TAG_USES + " tag."); } } } // Report any errors that we have collected that can be shown to the user // once we determine that this is an Automotive Media App. if (mIsAutomotiveMediaApp && !context.getProject().isLibrary() && mMainApplicationHandle != null && mDoAutomotiveAppCheck) { Element node = (Element) mMainApplicationHandle.getClientData(); if (!mMediaIntentFilterFound && context.isEnabled(MISSING_MEDIA_BROWSER_SERVICE_ACTION_ISSUE)) { context.report(MISSING_MEDIA_BROWSER_SERVICE_ACTION_ISSUE, node, mMainApplicationHandle.resolve(), "Missing `intent-filter` for action " + "`android.media.browse.MediaBrowserService` that is required for " + "android auto support"); } if (!mMediaSearchIntentFilterFound && context.isEnabled(MISSING_INTENT_FILTER_FOR_MEDIA_SEARCH)) { context.report(MISSING_INTENT_FILTER_FOR_MEDIA_SEARCH, node, mMainApplicationHandle.resolve(), "Missing `intent-filter` for action " + "`android.media.action.MEDIA_PLAY_FROM_SEARCH`."); } } } private void checkServiceForBrowserServiceIntentFilter(Element element) { if (TAG_SERVICE.equals(element.getTagName()) && !mMediaIntentFilterFound) { for (Element child : LintUtils.getChildren(element)) { String tagName = child.getTagName(); if (TAG_INTENT_FILTER.equals(tagName)) { for (Element filterChild : LintUtils.getChildren(child)) { if (NODE_ACTION.equals(filterChild.getTagName())) { String actionValue = filterChild.getAttributeNS(ANDROID_URI, ATTR_NAME); if (ACTION_MEDIA_BROWSER_SERVICE.equals(actionValue)) { mMediaIntentFilterFound = true; return; } } } } } } } private void checkForMediaSearchIntentFilter(Element element) { if (!mMediaSearchIntentFilterFound) { for (Element filterChild : LintUtils.getChildren(element)) { if (NODE_ACTION.equals(filterChild.getTagName())) { String actionValue = filterChild.getAttributeNS(ANDROID_URI, ATTR_NAME); if (ACTION_MEDIA_PLAY_FROM_SEARCH.equals(actionValue)) { mMediaSearchIntentFilterFound = true; break; } } } } } // Implementation of the JavaScanner @Override @Nullable public List<String> applicableSuperClasses() { // We currently enable scanning only for media apps. return mIsAutomotiveMediaApp ? Arrays.asList(CLASS_MEDIA_SESSION_CALLBACK, CLASS_V4MEDIA_SESSION_COMPAT_CALLBACK) : null; } @Override public void checkClass(@NonNull JavaContext context, @NonNull PsiClass declaration) { // Only check classes that are not declared abstract. if (!context.getEvaluator().isAbstract(declaration)) { MediaSessionCallbackVisitor visitor = new MediaSessionCallbackVisitor(context); declaration.accept(visitor); if (!visitor.isPlayFromSearchMethodFound() && context.isEnabled(MISSING_ON_PLAY_FROM_SEARCH)) { context.report(MISSING_ON_PLAY_FROM_SEARCH, declaration, context.getNameLocation(declaration), "This class does not override `" + METHOD_MEDIA_SESSION_PLAY_FROM_SEARCH + "` from `MediaSession.Callback`" + " The method should be overridden and implemented to support " + "Voice search on Android Auto."); } } } /** * A Visitor class to search for {@code MediaSession.Callback#onPlayFromSearch(..)} * method declaration. */ private static class MediaSessionCallbackVisitor extends JavaRecursiveElementVisitor { private final JavaContext mContext; private boolean mOnPlayFromSearchFound; public MediaSessionCallbackVisitor(JavaContext context) { this.mContext = context; } public boolean isPlayFromSearchMethodFound() { return mOnPlayFromSearchFound; } @Override public void visitMethod(PsiMethod method) { super.visitMethod(method); if (METHOD_MEDIA_SESSION_PLAY_FROM_SEARCH.equals(method.getName()) && mContext.getEvaluator().parametersMatch(method, TYPE_STRING, BUNDLE_ARG)) { mOnPlayFromSearchFound = true; } } } // Used by the IDE to show errors. @SuppressWarnings("unused") @NonNull public static String[] getAllowedAutomotiveAppTypes() { return new String[] { VAL_NAME_MEDIA, VAL_NAME_NOTIFICATION }; } }