| /* |
| * Copyright (C) 2011 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_BACKGROUND; |
| import static com.android.SdkConstants.ATTR_FOREGROUND; |
| import static com.android.SdkConstants.ATTR_LAYOUT; |
| import static com.android.SdkConstants.ATTR_LAYOUT_GRAVITY; |
| import static com.android.SdkConstants.DOT_JAVA; |
| import static com.android.SdkConstants.FRAME_LAYOUT; |
| import static com.android.SdkConstants.LAYOUT_RESOURCE_PREFIX; |
| import static com.android.SdkConstants.R_LAYOUT_RESOURCE_PREFIX; |
| import static com.android.SdkConstants.VIEW_INCLUDE; |
| |
| import com.android.annotations.NonNull; |
| import com.android.annotations.Nullable; |
| import com.android.tools.lint.detector.api.Category; |
| import com.android.tools.lint.detector.api.Context; |
| import com.android.tools.lint.detector.api.Detector; |
| 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.LayoutDetector; |
| import com.android.tools.lint.detector.api.LintUtils; |
| import com.android.tools.lint.detector.api.Location; |
| import com.android.tools.lint.detector.api.Location.Handle; |
| import com.android.tools.lint.detector.api.Scope; |
| import com.android.tools.lint.detector.api.Severity; |
| import com.android.tools.lint.detector.api.Speed; |
| import com.android.tools.lint.detector.api.XmlContext; |
| import com.android.utils.Pair; |
| |
| import org.w3c.dom.Element; |
| import org.w3c.dom.Node; |
| |
| import java.io.File; |
| import java.util.ArrayList; |
| import java.util.Arrays; |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.EnumSet; |
| import java.util.HashSet; |
| import java.util.List; |
| import java.util.Set; |
| |
| import lombok.ast.AstVisitor; |
| import lombok.ast.Expression; |
| import lombok.ast.MethodInvocation; |
| import lombok.ast.Select; |
| import lombok.ast.StrictListAccessor; |
| |
| /** |
| * Checks whether a root FrameLayout can be replaced with a {@code <merge>} tag. |
| */ |
| public class MergeRootFrameLayoutDetector extends LayoutDetector implements Detector.JavaScanner { |
| /** |
| * Set of layouts that we want to enable the warning for. We only warn for |
| * {@code <FrameLayout>}'s that are the root of a layout included from |
| * another layout, or directly referenced via a {@code setContentView} call. |
| */ |
| private Set<String> mWhitelistedLayouts; |
| |
| /** |
| * Set of pending [layout, location] pairs where the given layout is a |
| * FrameLayout that perhaps should be replaced by a {@code <merge>} tag (if |
| * the layout is included or set as the content view. This must be processed |
| * after the whole project has been scanned since the set of includes etc |
| * can be encountered after the included layout. |
| */ |
| private List<Pair<String, Location.Handle>> mPending; |
| |
| /** The main issue discovered by this detector */ |
| public static final Issue ISSUE = Issue.create( |
| "MergeRootFrame", //$NON-NLS-1$ |
| "FrameLayout can be replaced with `<merge>` tag", |
| |
| "If a `<FrameLayout>` is the root of a layout and does not provide background " + |
| "or padding etc, it can often be replaced with a `<merge>` tag which is slightly " + |
| "more efficient. Note that this depends on context, so make sure you understand " + |
| "how the `<merge>` tag works before proceeding.", |
| Category.PERFORMANCE, |
| 4, |
| Severity.WARNING, |
| new Implementation( |
| MergeRootFrameLayoutDetector.class, |
| EnumSet.of(Scope.ALL_RESOURCE_FILES, Scope.JAVA_FILE))) |
| .addMoreInfo( |
| "http://android-developers.blogspot.com/2009/03/android-layout-tricks-3-optimize-by.html"); //$NON-NLS-1$ |
| |
| /** Constructs a new {@link MergeRootFrameLayoutDetector} */ |
| public MergeRootFrameLayoutDetector() { |
| } |
| |
| @Override |
| @NonNull |
| public Speed getSpeed() { |
| return Speed.FAST; |
| } |
| |
| @Override |
| public boolean appliesTo(@NonNull Context context, @NonNull File file) { |
| return LintUtils.isXmlFile(file) || LintUtils.endsWith(file.getName(), DOT_JAVA); |
| } |
| |
| @Override |
| public void afterCheckProject(@NonNull Context context) { |
| if (mPending != null && mWhitelistedLayouts != null) { |
| // Process all the root FrameLayouts that are eligible, and generate |
| // suggestions for <merge> replacements for any layouts that are included |
| // from other layouts |
| for (Pair<String, Handle> pair : mPending) { |
| String layout = pair.getFirst(); |
| if (mWhitelistedLayouts.contains(layout)) { |
| Handle handle = pair.getSecond(); |
| |
| Object clientData = handle.getClientData(); |
| if (clientData instanceof Node) { |
| if (context.getDriver().isSuppressed(null, ISSUE, (Node) clientData)) { |
| return; |
| } |
| } |
| |
| Location location = handle.resolve(); |
| context.report(ISSUE, location, |
| "This `<FrameLayout>` can be replaced with a `<merge>` tag"); |
| } |
| } |
| } |
| } |
| |
| // Implements XmlScanner |
| |
| @Override |
| public Collection<String> getApplicableElements() { |
| return Arrays.asList(VIEW_INCLUDE, FRAME_LAYOUT); |
| } |
| |
| @Override |
| public void visitElement(@NonNull XmlContext context, @NonNull Element element) { |
| String tag = element.getTagName(); |
| if (tag.equals(VIEW_INCLUDE)) { |
| String layout = element.getAttribute(ATTR_LAYOUT); // NOTE: Not in android: namespace |
| if (layout.startsWith(LAYOUT_RESOURCE_PREFIX)) { // Ignore @android:layout/ layouts |
| layout = layout.substring(LAYOUT_RESOURCE_PREFIX.length()); |
| whiteListLayout(layout); |
| } |
| } else { |
| assert tag.equals(FRAME_LAYOUT); |
| if (LintUtils.isRootElement(element) && |
| ((isWidthFillParent(element) && isHeightFillParent(element)) || |
| !element.hasAttributeNS(ANDROID_URI, ATTR_LAYOUT_GRAVITY)) |
| && !element.hasAttributeNS(ANDROID_URI, ATTR_BACKGROUND) |
| && !element.hasAttributeNS(ANDROID_URI, ATTR_FOREGROUND) |
| && !hasPadding(element)) { |
| String layout = LintUtils.getLayoutName(context.file); |
| Handle handle = context.createLocationHandle(element); |
| handle.setClientData(element); |
| |
| if (!context.getProject().getReportIssues()) { |
| // If this is a library project not being analyzed, ignore it |
| return; |
| } |
| |
| if (mPending == null) { |
| mPending = new ArrayList<Pair<String,Handle>>(); |
| } |
| mPending.add(Pair.of(layout, handle)); |
| } |
| } |
| } |
| |
| private void whiteListLayout(String layout) { |
| if (mWhitelistedLayouts == null) { |
| mWhitelistedLayouts = new HashSet<String>(); |
| } |
| mWhitelistedLayouts.add(layout); |
| } |
| |
| // Implements JavaScanner |
| |
| @Override |
| public List<String> getApplicableMethodNames() { |
| return Collections.singletonList("setContentView"); //$NON-NLS-1$ |
| } |
| |
| @Override |
| public void visitMethod( |
| @NonNull JavaContext context, |
| @Nullable AstVisitor visitor, |
| @NonNull MethodInvocation node) { |
| StrictListAccessor<Expression, MethodInvocation> argumentList = node.astArguments(); |
| if (argumentList != null && argumentList.size() == 1) { |
| Expression argument = argumentList.first(); |
| if (argument instanceof Select) { |
| String expression = argument.toString(); |
| if (expression.startsWith(R_LAYOUT_RESOURCE_PREFIX)) { |
| whiteListLayout(expression.substring(R_LAYOUT_RESOURCE_PREFIX.length())); |
| } |
| } |
| } |
| } |
| } |
