RichEditor组件实现图片插入后换行并横向居中效果
============================

#### 问题现象

RichEditor组件如何实现文本中插入图片后，图片换行并横向居中的场景。

#### 背景知识

[RichEditor](https://developer.huawei.com/consumer/cn/doc/harmonyos-references/ts-basic-components-richeditor)是支持图文混排和文本交互式编辑的组件，适用于需要复杂文本输入的场景（如评论区、富文本编辑器）。

#### 解决方案

*   **方案一**：文本中插入图片后，图片换行并横向居中的场景，可以使用[addBuilderSpan](https://developer.huawei.com/consumer/cn/doc/harmonyos-references/ts-basic-components-richeditor#addbuilderspan11)在RichEditor中添加用户自定义布局（BuilderSpan），自定义布局中设置图片横向居中，并用Text组件设置换行。
    
    @Entry
    @Component
    struct BuilderSpanExample {
      controller: RichEditorController = new RichEditorController();
      option: RichEditorOptions = { controller: this.controller };
      private customBuilder: CustomBuilder = undefined;
    
      @Builder
      imageTextBuilder() {
        Row({ space: 2 }) {
         _ // $r('app.media.startIcon')需要替换为开发者所需的图像资源文件。_
          Image($r('app.media.startIcon')).width(24).height(24).margin({ left: -5 });
          Text('\\n').fontSize(10);
        }
        .width('100%')
        .height(50)
        .padding(5)
        .alignItems(VerticalAlign.Center)
        .justifyContent(FlexAlign.Center)
      }
    
      build() {
        Column() {
          Button('addImageTextBuilder')
            .onClick(() => {
              let insertOffset = this.controller.getCaretOffset();
              this.customBuilder = () => {
                this.imageTextBuilder();
              };
              this.controller.addBuilderSpan(this.customBuilder, { offset: insertOffset });
            })
          Column() {
            RichEditor(this.option)
              .onReady(() => {
                this.controller.addTextSpan('0123456789',
                  {
                    style:
                    {
                      fontColor: Color.Orange,
                      fontSize: 30
                    }
                  });
              })
          }
          .margin({ top: 60 })
          .borderWidth(1)
          .borderColor(Color.Red)
          .width('100%')
          .height('70%')
        }
      }
    }
    
*   **方案二**：文本中插入图片后，图片不换行并横向居中的场景，可以使用addBuilderSpan在RichEditor中添加用户自定义布局（BuilderSpan），自定义布局中设置图片横向居中，并用Text组件设置换行。
    
    @Entry
    @Component
    struct Index {
      controller: RichEditorController = new RichEditorController();
      option: RichEditorOptions = { controller: this.controller };
      private customBuilder: CustomBuilder = undefined;
      uiContext: UIContext = this.getUIContext();
      @State imageTextHeight: number = 50;
    
      @Builder
      imageTextBuilder() {
        Row({ space: 2 }) {
        _  // $r('app.media.startIcon')需要替换为开发者所需的图像资源文件。_
          Image($r('app.media.startIcon')).width(70).height(70).margin({ left: -5 });
        }
        .height(this.imageTextHeight)
        .padding(5)
        .alignItems(VerticalAlign.Center)
      }
    
      build() {
        Column() {
          Button('addImageTextBuilder')
            .onClick(() => {
              let insertOffset = this.controller.getCaretOffset();
              this.imageTextHeight = 70;
              this.customBuilder = () => {
                this.imageTextBuilder();
              };
              this.controller.addBuilderSpan(this.customBuilder, { offset: insertOffset });
              this.controller.updateSpanStyle({
                start: insertOffset - 1,
                end: insertOffset,
                textStyle: { lineHeight: this.imageTextHeight, halfLeading: true }
              });
            });
    
          Button('addText')
            .onClick(() => {
              let insertOffset = this.controller.getCaretOffset();
              this.controller.addTextSpan('一个测试',
                {
                  offset: insertOffset,
                  style:
                  {
                    fontColor: Color.Orange,
                    fontSize: 30
                  }
                });
            })
            .margin({ top: 10 })
          Column() {
            RichEditor(this.option)
              .onReady(() => {
                this.controller.addTextSpan('一个测试',
                  {
                    style:
                    {
                      fontColor: Color.Orange,
                      fontSize: 30
                    }
                  });
              })
          }
          .margin({ top: 60 })
          .width('100%')
          .height('70%');
        }
        .margin({ top: 50 })
      }
    }