designer/src/com/android/tools/idea/uibuilder/model/NlComponent.java - platform/tools/adt/idea - Git at Google

 /*
  * 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.idea.uibuilder.model;

 import com.android.annotations.NonNull;
 import com.android.annotations.Nullable;
 import com.android.ide.common.rendering.api.ViewInfo;
 import com.android.resources.ResourceType;
 import com.android.tools.idea.AndroidPsiUtils;
 import com.android.tools.idea.rendering.AppResourceRepository;
 import com.android.tools.idea.rendering.AttributeSnapshot;
 import com.android.tools.idea.rendering.ResourceHelper;
 import com.android.tools.idea.rendering.TagSnapshot;
 import com.android.tools.idea.uibuilder.api.InsertType;
 import com.android.tools.idea.uibuilder.api.ViewEditor;
 import com.android.tools.idea.uibuilder.api.ViewGroupHandler;
 import com.android.tools.idea.uibuilder.api.ViewHandler;
 import com.android.tools.idea.uibuilder.handlers.ViewEditorImpl;
 import com.android.tools.idea.uibuilder.handlers.ViewHandlerManager;
 import com.google.common.base.Objects;
 import com.google.common.collect.Lists;
 import com.intellij.lang.LanguageNamesValidation;
 import com.intellij.lang.java.JavaLanguage;
 import com.intellij.lang.refactoring.NamesValidator;
 import com.intellij.openapi.application.ApplicationManager;
 import com.intellij.openapi.module.Module;
 import com.intellij.openapi.project.Project;
 import com.intellij.openapi.util.Computable;
 import com.intellij.openapi.util.text.StringUtil;
 import com.intellij.psi.xml.XmlTag;
 import org.jetbrains.android.facet.AndroidFacet;

 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;

 import static com.android.SdkConstants.*;

 /**
  * Represents a component editable in the UI builder. A component has properties,
  * if visual it has bounds, etc.
  */
 public class NlComponent {
   @Nullable public List<NlComponent> children;
   @Nullable public ViewInfo viewInfo;
   @AndroidCoordinate public int x;
   @AndroidCoordinate public int y;
   @AndroidCoordinate public int w;
   @AndroidCoordinate public int h;
   private NlComponent myParent;
   @NonNull private final NlModel myModel;
   @NonNull private XmlTag myTag;
   @NonNull private String myTagName; // for non-read lock access elsewhere
   @Nullable private TagSnapshot snapshot;

   public NlComponent(@NonNull NlModel model, @NonNull XmlTag tag) {
     myModel = model;
     myTag = tag;
     myTagName = tag.getName();
   }

   @NonNull
   public XmlTag getTag() {
     return myTag;
   }

   @NonNull
   public NlModel getModel() {
     return myModel;
   }

   public void setTag(@NonNull XmlTag tag) {
     myTag = tag;
     myTagName = tag.getName();
   }

   public void setSnapshot(@Nullable TagSnapshot snapshot) {
     this.snapshot = snapshot;
   }

   public void setBounds(@AndroidCoordinate int x, @AndroidCoordinate int y, @AndroidCoordinate int w, @AndroidCoordinate int h) {
     this.x = x;
     this.y = y;
     this.w = w;
     this.h = h;
   }

   public void addChild(@NonNull NlComponent component) {
     addChild(component, null);
   }

   public void addChild(@NonNull NlComponent component, @Nullable NlComponent before) {
     if (children == null) {
       children = Lists.newArrayList();
     }
     int index = before != null ? children.indexOf(before) : -1;
     if (index != -1) {
       children.add(index, component);
     } else {
       children.add(component);
     }
     component.setParent(this);
   }

   public void delete() {
     NlComponent parent = getParent();
     if (parent != null) {
       parent.removeChild(this);
     }
     myTag.delete();
   }

   public void removeChild(@NonNull NlComponent component) {
     if (children != null) {
       children.remove(component);
     }
     component.setParent(null);
   }

   @NonNull
   public Iterable<NlComponent> getChildren() {
     return children != null ? children : Collections.<NlComponent>emptyList();
   }

   public int getChildCount() {
     return children != null ? children.size() : 0;
   }

   @Nullable
   public NlComponent getChild(int index) {
     return children != null && index >= 0 && index < children.size() ? children.get(index) : null;
   }

   @Nullable
   public NlComponent getNextSibling() {
     if (myParent == null) {
       return null;
     }
     for (int index = 0; index < myParent.getChildCount(); index++) {
       if (myParent.getChild(index) == this) {
         return myParent.getChild(index + 1);
       }
     }
     return null;
   }

   @Nullable
   public NlComponent findViewByTag(@NonNull XmlTag tag) {
     if (myTag == tag) {
       return this;
     }

     if (children != null) {
       for (NlComponent child : children) {
         NlComponent result = child.findViewByTag(tag);
         if (result != null) {
           return result;
         }
       }
     }

     return null;
   }

   @Nullable
   public List<NlComponent> findViewsByTag(@NonNull XmlTag tag) {
     List<NlComponent> result = null;

     if (children != null) {
       for (NlComponent child : children) {
         List<NlComponent> matches = child.findViewsByTag(tag);
         if (matches != null) {
           if (result != null) {
             result.addAll(matches);
           } else {
             result = matches;
           }
         }
       }
     }

     if (myTag == tag) {
       if (result == null) {
         return Lists.newArrayList(this);
       }
       result.add(this);
     }

     return result;
   }


   @Nullable
   public NlComponent findLeafAt(@AndroidCoordinate int px, @AndroidCoordinate int py) {
     if (children != null) {
       // Search BACKWARDS such that if the children are painted on top of each
       // other (as is the case in a FrameLayout) I pick the last one which will
       // be topmost!
       for (int i = children.size() - 1; i >= 0; i--) {
         NlComponent child = children.get(i);
         NlComponent result = child.findLeafAt(px, py);
         if (result != null) {
           return result;
         }
       }
     }

     return (x <= px && y <= py && x + w >= px && y + h >= py) ? this : null;
   }

   public boolean isRoot() {
     return !(myTag.getParent() instanceof XmlTag);
   }

   public NlComponent getRoot() {
     NlComponent component = this;
     while (component != null && !component.isRoot()) {
       component = component.getParent();
     }
     return component;
   }

   public static String toTree(@NonNull List<NlComponent> roots) {
     StringBuilder sb = new StringBuilder(200);
     for (NlComponent root : roots) {
       describe(sb, root, 0);
     }
     return sb.toString().trim();
   }

   private static void describe(@NonNull StringBuilder sb, @NonNull NlComponent component, int depth) {
     for (int i = 0; i < depth; i++) {
       sb.append("    ");
     }
     sb.append(describe(component));
     sb.append('\n');
     for (NlComponent child : component.getChildren()) {
       describe(sb, child, depth + 1);
     }
   }

   private static String describe(@NonNull NlComponent root) {
     return Objects.toStringHelper(root).omitNullValues()
       .add("tag", describe(root.myTag))
       .add("bounds",  "[" + root.x + "," + root.y + ":" + root.w + "x" + root.h)
       .toString();
   }

   private static String describe(@Nullable XmlTag tag) {
     if (tag == null) {
       return "";
     } else {
       return '<' + tag.getName() + '>';
     }
   }

   /** Returns the ID of this component */
   @Nullable
   public String getId() {
     String id = getAttribute(ANDROID_URI, ATTR_ID);
     if (id != null) {
       if (id.startsWith(NEW_ID_PREFIX)) {
         return id.substring(NEW_ID_PREFIX.length());
       } else if (id.startsWith(ID_PREFIX)) {
         return id.substring(ID_PREFIX.length());
       }
     }
     return null;
   }

   /**
    * Determines whether the given new component should have an id attribute.
    * This is generally false for layouts, and generally true for other views,
    * not including the {@code <include>} and {@code <merge>} tags. Note that
    * {@code <fragment>} tags <b>should</b> specify an id.
    *
    * @return true if the component should have a default id
    */
   public boolean needsDefaultId() {
     if (myTagName.equals(VIEW_INCLUDE) || myTagName.equals(VIEW_MERGE) || myTagName.equals(SPACE) || myTagName.equals(REQUEST_FOCUS) ||
         // Handle <Space> in the compatibility library package
         (myTagName.endsWith(SPACE) && myTagName.length() > SPACE.length() && myTagName.charAt(myTagName.length() - SPACE.length()) == '.')) {
       return false;
     }

     // Assign id's to ViewGroups like ListViews, but not to views like LinearLayout
     ViewHandler viewHandler = getViewHandler();
     if (viewHandler == null) {
       if (myTagName.endsWith("Layout")) {
         return false;
       }
     } else if (viewHandler instanceof ViewGroupHandler) {
       return false;
     }

     return true;
   }

   /** Returns the ID, but also assigns a default id if the component does not already have an id (even if the component does
    * not need one according to {@link #needsDefaultId()} */
   public String ensureId() {
     String id = getId();
     if (id != null) {
       return id;
     }

     return assignId();
   }

   public String assignId() {
     Collection<String> idList = getIds(myModel.getFacet());
     return assignId(this, idList);
   }

   public static String assignId(@NonNull NlComponent component, @NonNull Collection<String> idList) {
     String idValue = StringUtil.decapitalize(component.getTagName());

     Module module = component.getModel().getModule();
     Project project = module.getProject();
     idValue = ResourceHelper.prependResourcePrefix(module, idValue);

     String nextIdValue = idValue;
     int index = 0;

     // Ensure that we don't create something like "switch" as an id, which won't compile when used
     // in the R class
     NamesValidator validator = LanguageNamesValidation.INSTANCE.forLanguage(JavaLanguage.INSTANCE);

     while (idList.contains(nextIdValue) || validator != null && validator.isKeyword(nextIdValue, project)) {
       ++index;
       if (index == 1 && (validator == null || !validator.isKeyword(nextIdValue, project))) {
         nextIdValue = idValue;
       } else {
         nextIdValue = idValue + Integer.toString(index);
       }
     }

     String newId = idValue + (index == 0 ? "" : Integer.toString(index));
     component.setAttribute(ANDROID_URI, ATTR_ID, NEW_ID_PREFIX + newId);
     return newId;
   }

   /** Looks up the existing set of id's reachable from the given module */
   private static Collection<String> getIds(@NonNull AndroidFacet facet) {
     AppResourceRepository resources = AppResourceRepository.getAppResources(facet, true);
     return resources.getItemsOfType(ResourceType.ID);
   }

   public int getBaseline() {
     try {
       if (viewInfo != null) {
         Object viewObject = viewInfo.getViewObject();
         return (Integer)viewObject.getClass().getMethod("getBaseline").invoke(viewObject);
       }
     }
     catch (Throwable ignore) {
     }

     return -1;
   }

   private Insets myMargins;
   private Insets myPadding;

   private static int fixDefault(int value) {
     return value == Integer.MIN_VALUE ? 0 : value;
   }

   @NonNull
   public Insets getMargins() {
     if (myMargins == null) {
       if (viewInfo == null) {
         return Insets.NONE;
       }
       try {
         Object layoutParams = viewInfo.getLayoutParamsObject();
         Class<?> layoutClass = layoutParams.getClass();

         int left = fixDefault(layoutClass.getField("leftMargin").getInt(layoutParams));
         int top = fixDefault(layoutClass.getField("topMargin").getInt(layoutParams));
         int right = fixDefault(layoutClass.getField("rightMargin").getInt(layoutParams));
         int bottom = fixDefault(layoutClass.getField("bottomMargin").getInt(layoutParams));
         // Doesn't look like we need to read startMargin and endMargin here;
         // ViewGroup.MarginLayoutParams#doResolveMargins resolves and assigns values to the others

         if (left == 0 && top == 0 && right == 0 && bottom == 0) {
           myMargins = Insets.NONE;
         } else {
           myMargins = new Insets(left, top, right, bottom);
         }
       }
       catch (Throwable e) {
         myMargins = Insets.NONE;
       }
     }
     return myMargins;
   }

   @NonNull
   public Insets getPadding() {
     if (myPadding == null) {
       if (viewInfo == null) {
         return Insets.NONE;
       }
       try {
         Object layoutParams = viewInfo.getViewObject();
         Class<?> layoutClass = layoutParams.getClass();

         int left = fixDefault((Integer)layoutClass.getMethod("getPaddingLeft").invoke(layoutParams)); // TODO: getPaddingStart!
         int top = fixDefault((Integer)layoutClass.getMethod("getPaddingTop").invoke(layoutParams));
         int right = fixDefault((Integer)layoutClass.getMethod("getPaddingRight").invoke(layoutParams));
         int bottom = fixDefault((Integer)layoutClass.getMethod("getPaddingBottom").invoke(layoutParams));
         if (left == 0 && top == 0 && right == 0 && bottom == 0) {
           myPadding = Insets.NONE;
         } else {
           myPadding = new Insets(left, top, right, bottom);
         }
       }
       catch (Throwable e) {
         myPadding = Insets.NONE;
       }
     }
     return myPadding;
   }

   @Nullable
   public NlComponent getParent() {
     return myParent;
   }

   public void setParent(@Nullable NlComponent parent) {
     myParent = parent;
   }

   @NonNull
   public String getTagName() {
     return myTagName;
   }

   @Override
   public String toString() {
     return describe(this);
   }

   /** Convenience wrapper for now; this should be replaced with property lookup */
   public void setAttribute(@Nullable String namespace, @NonNull String attribute, @Nullable String value) {
     // Handle validity
     myTag.setAttribute(attribute, namespace, value);
     if (snapshot != null) {
       snapshot.setAttribute(attribute, namespace, null, value);
     }
   }

   @Nullable
   public String getAttribute(@Nullable String namespace, @NonNull String attribute) {
     if (snapshot != null) {
       return snapshot.getAttribute(attribute, namespace);
     } else if (myTag.isValid()) {
       return AndroidPsiUtils.getAttributeSafely(myTag, namespace, attribute);
     } else {
       // Newly created components for example
       return null;
     }
   }

   @NonNull
   public List<AttributeSnapshot> getAttributes() {
     if (snapshot != null) {
       return snapshot.attributes;
     }

     if (myTag.isValid()) {
       if (!ApplicationManager.getApplication().isReadAccessAllowed()) {
         return ApplicationManager.getApplication().runReadAction(new Computable<List<AttributeSnapshot>>() {
           @Override
           public List<AttributeSnapshot> compute() {
             return AttributeSnapshot.createAttributesForTag(myTag);
           }
         });
       }
       return AttributeSnapshot.createAttributesForTag(myTag);
     }

     return Collections.emptyList();
   }

   public String ensureNamespace(@NonNull String prefix, @NonNull String namespace) {
     //todo: Merge with functionality in {@link SuppressLintIntentionAction#ensureNamespaceImported}
     assert isRoot();
     // Handle validity
     String existingPrefix = myTag.getPrefixByNamespace(namespace);
     if (existingPrefix != null) {
       return existingPrefix;
     }
     if (myTag.getAttribute(XMLNS_PREFIX + prefix) != null) {
       String base = prefix;
       for (int i = 2; ; i++) {
         prefix = base + Integer.toString(i);
         if (myTag.getAttribute(XMLNS_PREFIX + prefix) == null) {
           break;
         }
       }
     }
     myTag.setAttribute(XMLNS_PREFIX + prefix, namespace);
     return prefix;
   }

   public boolean isShowing() {
     return snapshot != null;
   }

   @Nullable
   public ViewHandler getViewHandler() {
     return ViewHandlerManager.get(myTag.getProject()).getHandler(this);
   }

   /**
    * Creates a new child of the given type, and inserts it before the given sibling (or null to append at the end).
    * Note: This operation can only be called when the caller is already holding a write lock. This will be the
    * case from {@link ViewHandler} callbacks such as {@link ViewHandler#onCreate(ViewEditor, NlComponent, NlComponent, InsertType)}
    * and {@link com.android.tools.idea.uibuilder.api.DragHandler#commit(int, int, int)}.
    *
    * @param editor     The editor showing the component
    * @param fqcn       The fully qualified name of the widget to insert, such as {@code android.widget.LinearLayout}
    *                   You can also pass XML tags here (this is typically the same as the fully qualified class name
    *                   of the custom view, but for Android framework views in the android.view or android.widget packages,
    *                   you can omit the package.)
    * @param before     The sibling to insert immediately before, or null to append
    * @param insertType The type of insertion
    */
   public NlComponent createChild(@NonNull ViewEditor editor,
                                  @NonNull String fqcn,
                                  @Nullable NlComponent before,
                                  @NonNull InsertType insertType) {
     return myModel.createComponent(((ViewEditorImpl)editor).getScreenView(), fqcn, this, before, insertType);
   }

   /**
    * Returns true if views with the given fully qualified class name need to include
    * their package in the layout XML tag
    *
    * @param fqcn the fully qualified class name, such as android.widget.Button
    * @return true if the full package path should be included in the layout XML element
    *         tag
    */
   private static boolean viewNeedsPackage(String fqcn) {
     return !(fqcn.startsWith(ANDROID_WIDGET_PREFIX)
              || fqcn.startsWith(ANDROID_VIEW_PKG)
              || fqcn.startsWith(ANDROID_WEBKIT_PKG));
   }

   /**
    * Maps a custom view class to the corresponding layout tag;
    * e.g. {@code android.widget.LinearLayout} maps to just {@code LinearLayout}, but
    * {@code android.support.v4.widget.DrawerLayout} maps to
    * {@code android.support.v4.widget.DrawerLayout}.
    *
    * @param fqcn fully qualified class name
    * @return the corresponding view tag
    */
   @NonNull
   public static String viewClassToTag(@NonNull String fqcn) {
     if (!viewNeedsPackage(fqcn)) {
       return fqcn.substring(fqcn.lastIndexOf('.') + 1);
     }

     return fqcn;
   }
 }
	/*
	* 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.idea.uibuilder.model;

	import com.android.annotations.NonNull;
	import com.android.annotations.Nullable;
	import com.android.ide.common.rendering.api.ViewInfo;
	import com.android.resources.ResourceType;
	import com.android.tools.idea.AndroidPsiUtils;
	import com.android.tools.idea.rendering.AppResourceRepository;
	import com.android.tools.idea.rendering.AttributeSnapshot;
	import com.android.tools.idea.rendering.ResourceHelper;
	import com.android.tools.idea.rendering.TagSnapshot;
	import com.android.tools.idea.uibuilder.api.InsertType;
	import com.android.tools.idea.uibuilder.api.ViewEditor;
	import com.android.tools.idea.uibuilder.api.ViewGroupHandler;
	import com.android.tools.idea.uibuilder.api.ViewHandler;
	import com.android.tools.idea.uibuilder.handlers.ViewEditorImpl;
	import com.android.tools.idea.uibuilder.handlers.ViewHandlerManager;
	import com.google.common.base.Objects;
	import com.google.common.collect.Lists;
	import com.intellij.lang.LanguageNamesValidation;
	import com.intellij.lang.java.JavaLanguage;
	import com.intellij.lang.refactoring.NamesValidator;
	import com.intellij.openapi.application.ApplicationManager;
	import com.intellij.openapi.module.Module;
	import com.intellij.openapi.project.Project;
	import com.intellij.openapi.util.Computable;
	import com.intellij.openapi.util.text.StringUtil;
	import com.intellij.psi.xml.XmlTag;
	import org.jetbrains.android.facet.AndroidFacet;

	import java.util.Collection;
	import java.util.Collections;
	import java.util.List;

	import static com.android.SdkConstants.*;

	/**
	* Represents a component editable in the UI builder. A component has properties,
	* if visual it has bounds, etc.
	*/
	public class NlComponent {
	@Nullable public List<NlComponent> children;
	@Nullable public ViewInfo viewInfo;
	@AndroidCoordinate public int x;
	@AndroidCoordinate public int y;
	@AndroidCoordinate public int w;
	@AndroidCoordinate public int h;
	private NlComponent myParent;
	@NonNull private final NlModel myModel;
	@NonNull private XmlTag myTag;
	@NonNull private String myTagName; // for non-read lock access elsewhere
	@Nullable private TagSnapshot snapshot;

	public NlComponent(@NonNull NlModel model, @NonNull XmlTag tag) {
	myModel = model;
	myTag = tag;
	myTagName = tag.getName();
	}

	@NonNull
	public XmlTag getTag() {
	return myTag;
	}

	@NonNull
	public NlModel getModel() {
	return myModel;
	}

	public void setTag(@NonNull XmlTag tag) {
	myTag = tag;
	myTagName = tag.getName();
	}

	public void setSnapshot(@Nullable TagSnapshot snapshot) {
	this.snapshot = snapshot;
	}

	public void setBounds(@AndroidCoordinate int x, @AndroidCoordinate int y, @AndroidCoordinate int w, @AndroidCoordinate int h) {
	this.x = x;
	this.y = y;
	this.w = w;
	this.h = h;
	}

	public void addChild(@NonNull NlComponent component) {
	addChild(component, null);
	}

	public void addChild(@NonNull NlComponent component, @Nullable NlComponent before) {
	if (children == null) {
	children = Lists.newArrayList();
	}
	int index = before != null ? children.indexOf(before) : -1;
	if (index != -1) {
	children.add(index, component);
	} else {
	children.add(component);
	}
	component.setParent(this);
	}

	public void delete() {
	NlComponent parent = getParent();
	if (parent != null) {
	parent.removeChild(this);
	}
	myTag.delete();
	}

	public void removeChild(@NonNull NlComponent component) {
	if (children != null) {
	children.remove(component);
	}
	component.setParent(null);
	}

	@NonNull
	public Iterable<NlComponent> getChildren() {
	return children != null ? children : Collections.<NlComponent>emptyList();
	}

	public int getChildCount() {
	return children != null ? children.size() : 0;
	}

	@Nullable
	public NlComponent getChild(int index) {
	return children != null && index >= 0 && index < children.size() ? children.get(index) : null;
	}

	@Nullable
	public NlComponent getNextSibling() {
	if (myParent == null) {
	return null;
	}
	for (int index = 0; index < myParent.getChildCount(); index++) {
	if (myParent.getChild(index) == this) {
	return myParent.getChild(index + 1);
	}
	}
	return null;
	}

	@Nullable
	public NlComponent findViewByTag(@NonNull XmlTag tag) {
	if (myTag == tag) {
	return this;
	}

	if (children != null) {
	for (NlComponent child : children) {
	NlComponent result = child.findViewByTag(tag);
	if (result != null) {
	return result;
	}
	}
	}

	return null;
	}

	@Nullable
	public List<NlComponent> findViewsByTag(@NonNull XmlTag tag) {
	List<NlComponent> result = null;

	if (children != null) {
	for (NlComponent child : children) {
	List<NlComponent> matches = child.findViewsByTag(tag);
	if (matches != null) {
	if (result != null) {
	result.addAll(matches);
	} else {
	result = matches;
	}
	}
	}
	}

	if (myTag == tag) {
	if (result == null) {
	return Lists.newArrayList(this);
	}
	result.add(this);
	}

	return result;
	}


	@Nullable
	public NlComponent findLeafAt(@AndroidCoordinate int px, @AndroidCoordinate int py) {
	if (children != null) {
	// Search BACKWARDS such that if the children are painted on top of each
	// other (as is the case in a FrameLayout) I pick the last one which will
	// be topmost!
	for (int i = children.size() - 1; i >= 0; i--) {
	NlComponent child = children.get(i);
	NlComponent result = child.findLeafAt(px, py);
	if (result != null) {
	return result;
	}
	}
	}

	return (x <= px && y <= py && x + w >= px && y + h >= py) ? this : null;
	}

	public boolean isRoot() {
	return !(myTag.getParent() instanceof XmlTag);
	}

	public NlComponent getRoot() {
	NlComponent component = this;
	while (component != null && !component.isRoot()) {
	component = component.getParent();
	}
	return component;
	}

	public static String toTree(@NonNull List<NlComponent> roots) {
	StringBuilder sb = new StringBuilder(200);
	for (NlComponent root : roots) {
	describe(sb, root, 0);
	}
	return sb.toString().trim();
	}

	private static void describe(@NonNull StringBuilder sb, @NonNull NlComponent component, int depth) {
	for (int i = 0; i < depth; i++) {
	sb.append(" ");
	}
	sb.append(describe(component));
	sb.append('\n');
	for (NlComponent child : component.getChildren()) {
	describe(sb, child, depth + 1);
	}
	}

	private static String describe(@NonNull NlComponent root) {
	return Objects.toStringHelper(root).omitNullValues()
	.add("tag", describe(root.myTag))
	.add("bounds", "[" + root.x + "," + root.y + ":" + root.w + "x" + root.h)
	.toString();
	}

	private static String describe(@Nullable XmlTag tag) {
	if (tag == null) {
	return "";
	} else {
	return '<' + tag.getName() + '>';
	}
	}

	/** Returns the ID of this component */
	@Nullable
	public String getId() {
	String id = getAttribute(ANDROID_URI, ATTR_ID);
	if (id != null) {
	if (id.startsWith(NEW_ID_PREFIX)) {
	return id.substring(NEW_ID_PREFIX.length());
	} else if (id.startsWith(ID_PREFIX)) {
	return id.substring(ID_PREFIX.length());
	}
	}
	return null;
	}

	/**
	* Determines whether the given new component should have an id attribute.
	* This is generally false for layouts, and generally true for other views,
	* not including the {@code <include>} and {@code <merge>} tags. Note that
	* {@code <fragment>} tags <b>should</b> specify an id.
	*
	* @return true if the component should have a default id
	*/
	public boolean needsDefaultId() {
	if (myTagName.equals(VIEW_INCLUDE) \|\| myTagName.equals(VIEW_MERGE) \|\| myTagName.equals(SPACE) \|\| myTagName.equals(REQUEST_FOCUS) \|\|
	// Handle <Space> in the compatibility library package
	(myTagName.endsWith(SPACE) && myTagName.length() > SPACE.length() && myTagName.charAt(myTagName.length() - SPACE.length()) == '.')) {
	return false;
	}

	// Assign id's to ViewGroups like ListViews, but not to views like LinearLayout
	ViewHandler viewHandler = getViewHandler();
	if (viewHandler == null) {
	if (myTagName.endsWith("Layout")) {
	return false;
	}
	} else if (viewHandler instanceof ViewGroupHandler) {
	return false;
	}

	return true;
	}

	/** Returns the ID, but also assigns a default id if the component does not already have an id (even if the component does
	* not need one according to {@link #needsDefaultId()} */
	public String ensureId() {
	String id = getId();
	if (id != null) {
	return id;
	}

	return assignId();
	}

	public String assignId() {
	Collection<String> idList = getIds(myModel.getFacet());
	return assignId(this, idList);
	}

	public static String assignId(@NonNull NlComponent component, @NonNull Collection<String> idList) {
	String idValue = StringUtil.decapitalize(component.getTagName());

	Module module = component.getModel().getModule();
	Project project = module.getProject();
	idValue = ResourceHelper.prependResourcePrefix(module, idValue);

	String nextIdValue = idValue;
	int index = 0;

	// Ensure that we don't create something like "switch" as an id, which won't compile when used
	// in the R class
	NamesValidator validator = LanguageNamesValidation.INSTANCE.forLanguage(JavaLanguage.INSTANCE);

	while (idList.contains(nextIdValue) \|\| validator != null && validator.isKeyword(nextIdValue, project)) {
	++index;
	if (index == 1 && (validator == null \|\| !validator.isKeyword(nextIdValue, project))) {
	nextIdValue = idValue;
	} else {
	nextIdValue = idValue + Integer.toString(index);
	}
	}

	String newId = idValue + (index == 0 ? "" : Integer.toString(index));
	component.setAttribute(ANDROID_URI, ATTR_ID, NEW_ID_PREFIX + newId);
	return newId;
	}

	/** Looks up the existing set of id's reachable from the given module */
	private static Collection<String> getIds(@NonNull AndroidFacet facet) {
	AppResourceRepository resources = AppResourceRepository.getAppResources(facet, true);
	return resources.getItemsOfType(ResourceType.ID);
	}

	public int getBaseline() {
	try {
	if (viewInfo != null) {
	Object viewObject = viewInfo.getViewObject();
	return (Integer)viewObject.getClass().getMethod("getBaseline").invoke(viewObject);
	}
	}
	catch (Throwable ignore) {
	}

	return -1;
	}

	private Insets myMargins;
	private Insets myPadding;

	private static int fixDefault(int value) {
	return value == Integer.MIN_VALUE ? 0 : value;
	}

	@NonNull
	public Insets getMargins() {
	if (myMargins == null) {
	if (viewInfo == null) {
	return Insets.NONE;
	}
	try {
	Object layoutParams = viewInfo.getLayoutParamsObject();
	Class<?> layoutClass = layoutParams.getClass();

	int left = fixDefault(layoutClass.getField("leftMargin").getInt(layoutParams));
	int top = fixDefault(layoutClass.getField("topMargin").getInt(layoutParams));
	int right = fixDefault(layoutClass.getField("rightMargin").getInt(layoutParams));
	int bottom = fixDefault(layoutClass.getField("bottomMargin").getInt(layoutParams));
	// Doesn't look like we need to read startMargin and endMargin here;
	// ViewGroup.MarginLayoutParams#doResolveMargins resolves and assigns values to the others

	if (left == 0 && top == 0 && right == 0 && bottom == 0) {
	myMargins = Insets.NONE;
	} else {
	myMargins = new Insets(left, top, right, bottom);
	}
	}
	catch (Throwable e) {
	myMargins = Insets.NONE;
	}
	}
	return myMargins;
	}

	@NonNull
	public Insets getPadding() {
	if (myPadding == null) {
	if (viewInfo == null) {
	return Insets.NONE;
	}
	try {
	Object layoutParams = viewInfo.getViewObject();
	Class<?> layoutClass = layoutParams.getClass();

	int left = fixDefault((Integer)layoutClass.getMethod("getPaddingLeft").invoke(layoutParams)); // TODO: getPaddingStart!
	int top = fixDefault((Integer)layoutClass.getMethod("getPaddingTop").invoke(layoutParams));
	int right = fixDefault((Integer)layoutClass.getMethod("getPaddingRight").invoke(layoutParams));
	int bottom = fixDefault((Integer)layoutClass.getMethod("getPaddingBottom").invoke(layoutParams));
	if (left == 0 && top == 0 && right == 0 && bottom == 0) {
	myPadding = Insets.NONE;
	} else {
	myPadding = new Insets(left, top, right, bottom);
	}
	}
	catch (Throwable e) {
	myPadding = Insets.NONE;
	}
	}
	return myPadding;
	}

	@Nullable
	public NlComponent getParent() {
	return myParent;
	}

	public void setParent(@Nullable NlComponent parent) {
	myParent = parent;
	}

	@NonNull
	public String getTagName() {
	return myTagName;
	}

	@Override
	public String toString() {
	return describe(this);
	}

	/** Convenience wrapper for now; this should be replaced with property lookup */
	public void setAttribute(@Nullable String namespace, @NonNull String attribute, @Nullable String value) {
	// Handle validity
	myTag.setAttribute(attribute, namespace, value);
	if (snapshot != null) {
	snapshot.setAttribute(attribute, namespace, null, value);
	}
	}

	@Nullable
	public String getAttribute(@Nullable String namespace, @NonNull String attribute) {
	if (snapshot != null) {
	return snapshot.getAttribute(attribute, namespace);
	} else if (myTag.isValid()) {
	return AndroidPsiUtils.getAttributeSafely(myTag, namespace, attribute);
	} else {
	// Newly created components for example
	return null;
	}
	}

	@NonNull
	public List<AttributeSnapshot> getAttributes() {
	if (snapshot != null) {
	return snapshot.attributes;
	}

	if (myTag.isValid()) {
	if (!ApplicationManager.getApplication().isReadAccessAllowed()) {
	return ApplicationManager.getApplication().runReadAction(new Computable<List<AttributeSnapshot>>() {
	@Override
	public List<AttributeSnapshot> compute() {
	return AttributeSnapshot.createAttributesForTag(myTag);
	}
	});
	}
	return AttributeSnapshot.createAttributesForTag(myTag);
	}

	return Collections.emptyList();
	}

	public String ensureNamespace(@NonNull String prefix, @NonNull String namespace) {
	//todo: Merge with functionality in {@link SuppressLintIntentionAction#ensureNamespaceImported}
	assert isRoot();
	// Handle validity
	String existingPrefix = myTag.getPrefixByNamespace(namespace);
	if (existingPrefix != null) {
	return existingPrefix;
	}
	if (myTag.getAttribute(XMLNS_PREFIX + prefix) != null) {
	String base = prefix;
	for (int i = 2; ; i++) {
	prefix = base + Integer.toString(i);
	if (myTag.getAttribute(XMLNS_PREFIX + prefix) == null) {
	break;
	}
	}
	}
	myTag.setAttribute(XMLNS_PREFIX + prefix, namespace);
	return prefix;
	}

	public boolean isShowing() {
	return snapshot != null;
	}

	@Nullable
	public ViewHandler getViewHandler() {
	return ViewHandlerManager.get(myTag.getProject()).getHandler(this);
	}

	/**
	* Creates a new child of the given type, and inserts it before the given sibling (or null to append at the end).
	* Note: This operation can only be called when the caller is already holding a write lock. This will be the
	* case from {@link ViewHandler} callbacks such as {@link ViewHandler#onCreate(ViewEditor, NlComponent, NlComponent, InsertType)}
	* and {@link com.android.tools.idea.uibuilder.api.DragHandler#commit(int, int, int)}.
	*
	* @param editor The editor showing the component
	* @param fqcn The fully qualified name of the widget to insert, such as {@code android.widget.LinearLayout}
	* You can also pass XML tags here (this is typically the same as the fully qualified class name
	* of the custom view, but for Android framework views in the android.view or android.widget packages,
	* you can omit the package.)
	* @param before The sibling to insert immediately before, or null to append
	* @param insertType The type of insertion
	*/
	public NlComponent createChild(@NonNull ViewEditor editor,
	@NonNull String fqcn,
	@Nullable NlComponent before,
	@NonNull InsertType insertType) {
	return myModel.createComponent(((ViewEditorImpl)editor).getScreenView(), fqcn, this, before, insertType);
	}

	/**
	* Returns true if views with the given fully qualified class name need to include
	* their package in the layout XML tag
	*
	* @param fqcn the fully qualified class name, such as android.widget.Button
	* @return true if the full package path should be included in the layout XML element
	* tag
	*/
	private static boolean viewNeedsPackage(String fqcn) {
	return !(fqcn.startsWith(ANDROID_WIDGET_PREFIX)
	\|\| fqcn.startsWith(ANDROID_VIEW_PKG)
	\|\| fqcn.startsWith(ANDROID_WEBKIT_PKG));
	}

	/**
	* Maps a custom view class to the corresponding layout tag;
	* e.g. {@code android.widget.LinearLayout} maps to just {@code LinearLayout}, but
	* {@code android.support.v4.widget.DrawerLayout} maps to
	* {@code android.support.v4.widget.DrawerLayout}.
	*
	* @param fqcn fully qualified class name
	* @return the corresponding view tag
	*/
	@NonNull
	public static String viewClassToTag(@NonNull String fqcn) {
	if (!viewNeedsPackage(fqcn)) {
	return fqcn.substring(fqcn.lastIndexOf('.') + 1);
	}

	return fqcn;
	}
	}