How to Limit the Number of Lines Displayed for the Placeholder Property of the RichEditor Component?

#harmonyos #richeditorcomponent #placeholdercustomization #textlinelimitation

Read the original article：How to Limit the Number of Lines Displayed for the Placeholder Property of the RichEditor Component?

Question

Short Answer

Use a Stack container with a Text component to simulate the placeholder effect with the following steps:

Overlay Components: Place RichEditor and Text inside a Stack to layer the placeholder text over the editor.
Text Truncation:
- Set maxLines(1) to restrict the text to one line.
- Use textOverflow({ overflow: TextOverflow.Ellipsis }) to truncate excess text with ellipsis.
Event Handling:
- Monitor onEditingChange to hide the placeholder when the user starts editing.
- Use hitTestBehavior(HitTestMode.Transparent) to ensure the Text does not block user interactions with the RichEditor.

Here you can find the related code example:

@Entry
@Component
struct Index {
  tips: string = 'This is sample text, with any excess truncated. Here is the sample text, with ellipses displayed for any excess.';
  controller: RichEditorController = new RichEditorController();
  options: RichEditorOptions = { controller: this.controller };
  @State flag: boolean = false

  build() {
    Column() {
      Stack() {
        RichEditor(this.options)
          .onEditingChange((isEditing: boolean) => {
            this.flag = isEditing
          })
          .width(300)
          .height(300)

        Text(`${!this.flag && (this.controller.getSpans()).length < 1 ? this.tips : ''}`)
          .width(250) // Set text box width
          .maxLines(1) // Limit display to one line
          .textOverflow({ overflow: TextOverflow.Ellipsis }) // Hide excess text
          .border({ width: 5 })
          .hitTestBehavior(HitTestMode.Transparent)
          .fontColor(Color.Gray)
          .border({
            width: 0
          })
          .position({
            top: 0,
            left: 0
          })
      }
    }.height('100%').width('100%')
    .justifyContent(FlexAlign.Center)
  }
}