reactjs - 焦点编辑器，将光标定位在第一个块的开头

Question

我需要将焦点应用到 Draft.js 编辑器并将光标定位在第一行/块的开头。编辑器包含多行/块。

仅this.refs.editor.focus()在应用时，光标始终位于编辑器中第二个块/行的开头。

使用这个问题和这个问题作为指导，我尝试了下面的代码但没有成功。我怀疑传递blockMap给createFromBlockArray()不正确：

focusTopLine() {

  this.refs.editor.focus();

  const { editorState } = this.state;
  const contentState = editorState.getCurrentContent();
  const selectionState = editorState.getSelection();
  const blockMap = contentState.getBlockMap();

  const newContentState = ContentState.createFromBlockArray(blockMap);
  const newEditorState = EditorState.createWithContent(newContentState);

  this.setState({
    editorState: EditorState.forceSelection(newEditorState, selectionState)
  });
}

Answer 1

您可以（可能，我没有测试过）这样做类似于如何EditorState.moveFocusToEnd()实现：

EditorState首先，在第一个块被选中的地方创建一个新的：

function moveSelectionToStart(editorState) {
  const content = editorState.getCurrentContent()
  const firstBlock = content.getFirstBlock()
  const firstKey = firstBlock.getKey()
  const length = firstBlock.getLength()

  return EditorState.acceptSelection(
    editorState,
    new SelectionState({
      anchorKey: firstKey,
      anchorOffset: length,
      focusKey: firstKey,
      focusOffset: length,
      isBackward: false,
    })
  )
}

然后用它来移动焦点：

function moveFocusToStart(editorState) {
  const afterSelectionMove = EditorState.moveSelectionToStart(editorState)
  return EditorState.forceSelection(
    afterSelectionMove,
    afterSelectionMove.getSelection()
  )
}

现在可以像这样使用它：

this.setState({ editorState: moveFocusToStart(editorState) })

Answer 2

我认为您也可以使用merge, 来设置焦点和锚点偏移，如下所示：

function moveFocusToStart(editorState: EditorState): EditorState {
  const selectionState = editorState.getSelection();
  return EditorState.forceSelection(
    editorState,
    selectionState.merge({
      anchorOffset: 0,
      focusOffset: 0,
    }),
  );
}