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https://github.com/zhigang1992/react-native.git
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4e841f2114
Summary: When a user clicks on some text, `RCTSurfaceTouchHandler` will call into a method on `RCTParagraphComponentView`. That method (i.e: `touchEventEmitter`) would be responsible for identifying the closest ancestral `<Text/>` component to which we should dispatch the `onPress` event, given the point where the user clicked. To answer this query, we'll use a data structure called `UIAttributedString`. This data structure represents a string, and a corresponding mapping from sequences of its characters to some arbitrary data. In this attributed string, we'll map sequences of characters to their closest ancestral `ParagraphShadowNode` or `TextShadowNode`. That way, when we get a click event on `RCTParagraphComponentView`, we can just look at the character that was clicked, and use that information to do a lookup in the attributed string to find the shadow node who's EventEmitter is responsible for processing the click event. Reviewed By: shergin Differential Revision: D9696904 fbshipit-source-id: a199649981ad271afa85414ce4c3f056851348be
58 lines
1.8 KiB
C++
58 lines
1.8 KiB
C++
/**
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* Copyright (c) 2015-present, Facebook, Inc.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*/
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#include "BaseTextShadowNode.h"
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#include <fabric/components/text/RawTextShadowNode.h>
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#include <fabric/components/text/RawTextProps.h>
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#include <fabric/components/text/TextShadowNode.h>
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#include <fabric/components/text/TextProps.h>
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#include <fabric/debug/DebugStringConvertibleItem.h>
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namespace facebook {
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namespace react {
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AttributedString BaseTextShadowNode::getAttributedString(
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const TextAttributes &textAttributes,
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const SharedShadowNode &parentNode
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) const {
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AttributedString attributedString;
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for (const auto &childNode : parentNode->getChildren()) {
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// RawShadowNode
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auto rawTextShadowNode = std::dynamic_pointer_cast<const RawTextShadowNode>(childNode);
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if (rawTextShadowNode) {
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AttributedString::Fragment fragment;
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fragment.string = rawTextShadowNode->getProps()->text;
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fragment.textAttributes = textAttributes;
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fragment.parentShadowNode = parentNode;
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attributedString.appendFragment(fragment);
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continue;
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}
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// TextShadowNode
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auto textShadowNode = std::dynamic_pointer_cast<const TextShadowNode>(childNode);
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if (textShadowNode) {
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TextAttributes localTextAttributes = textAttributes;
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localTextAttributes.apply(textShadowNode->getProps()->textAttributes);
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attributedString.appendAttributedString(textShadowNode->getAttributedString(localTextAttributes, textShadowNode));
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continue;
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}
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// Any other kind of ShadowNode
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AttributedString::Fragment fragment;
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fragment.shadowNode = childNode;
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fragment.textAttributes = textAttributes;
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attributedString.appendFragment(fragment);
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}
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return attributedString;
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}
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} // namespace react
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} // namespace facebook
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