| /* |
| * Copyright (C) 2014 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_LAYOUT_HEIGHT; |
| import static com.android.SdkConstants.ATTR_LAYOUT_WIDTH; |
| import static com.android.SdkConstants.VALUE_WRAP_CONTENT; |
| import static com.android.SdkConstants.WEB_VIEW; |
| |
| import com.android.annotations.NonNull; |
| import com.android.tools.lint.detector.api.Category; |
| import com.android.tools.lint.detector.api.Implementation; |
| import com.android.tools.lint.detector.api.Issue; |
| import com.android.tools.lint.detector.api.LayoutDetector; |
| import com.android.tools.lint.detector.api.Location; |
| 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 org.w3c.dom.Attr; |
| import org.w3c.dom.Element; |
| import org.w3c.dom.Node; |
| |
| import java.util.Collection; |
| import java.util.Collections; |
| |
| public class WebViewDetector extends LayoutDetector { |
| private static final Implementation IMPLEMENTATION = new Implementation( |
| WebViewDetector.class, |
| Scope.RESOURCE_FILE_SCOPE); |
| |
| /** The main issue discovered by this detector */ |
| public static final Issue ISSUE = Issue.create( |
| "WebViewLayout", //$NON-NLS-1$ |
| "WebViews in wrap_content parents", |
| |
| "The WebView implementation has certain performance optimizations which will not " + |
| "work correctly if the parent view is using `wrap_content` rather than " + |
| "`match_parent`. This can lead to subtle UI bugs.", |
| |
| Category.CORRECTNESS, |
| 7, |
| Severity.ERROR, |
| IMPLEMENTATION); |
| |
| /** Constructs a new {@link WebViewDetector} */ |
| public WebViewDetector() { |
| } |
| |
| @NonNull |
| @Override |
| public Speed getSpeed() { |
| return Speed.FAST; |
| } |
| |
| @Override |
| public Collection<String> getApplicableElements() { |
| return Collections.singletonList(WEB_VIEW); |
| } |
| |
| @Override |
| public void visitElement(@NonNull XmlContext context, @NonNull Element element) { |
| Node parentNode = element.getParentNode(); |
| if (parentNode != null && parentNode.getNodeType() == Node.ELEMENT_NODE) { |
| Element parent = (Element)parentNode; |
| Attr width = parent.getAttributeNodeNS(ANDROID_URI, ATTR_LAYOUT_WIDTH); |
| Attr height = parent.getAttributeNodeNS(ANDROID_URI, ATTR_LAYOUT_HEIGHT); |
| Attr attr = null; |
| if (width != null && VALUE_WRAP_CONTENT.equals(width.getValue())) { |
| attr = width; |
| } |
| if (height != null && VALUE_WRAP_CONTENT.equals(height.getValue())) { |
| attr = height; |
| } |
| if (attr != null) { |
| String message = String.format("Placing a `<WebView>` in a parent element that " |
| + "uses a `wrap_content %1$s` can lead to subtle bugs; use `match_parent` " |
| + "instead", attr.getLocalName()); |
| Location location = context.getLocation(element); |
| Location secondary = context.getLocation(attr); |
| secondary.setMessage("`wrap_content` here may not work well with WebView below"); |
| location.setSecondary(secondary); |
| context.report(ISSUE, element, location, message); |
| } |
| } |
| } |
| } |