How to use

com.intellij.codeInsight.completion.CodeCompletionHandlerBase

constructor

/**
 * Handles QuickFix action invoked on {@link IgnoreSyntax}.
 *
 * @param project      the {@link Project} containing the working file
 * @param file         the {@link PsiFile} containing handled entry
 * @param startElement the {@link IgnoreSyntax} that will be selected and replaced
 * @param endElement   the {@link PsiElement} which is ignored in invoked action
 */
@Override
public void invoke(@NotNull Project project, @NotNull PsiFile file,
          @Nullable("is null when called from inspection") Editor editor,
          @NotNull PsiElement startElement, @NotNull PsiElement endElement) {
  if (startElement instanceof IgnoreSyntax) {
    PsiElement value = ((IgnoreSyntax) startElement).getValue();
    if (editor != null) {
      editor.getSelectionModel().setSelection(
          value.getTextOffset(),
          value.getTextOffset() + value.getTextLength()
      );
    }
    new CodeCompletionHandlerBase(CompletionType.BASIC).invokeCompletion(project, editor);
  }
}

 @Override
 public void handleInsert(@NotNull final InsertionContext context, @NotNull LookupElement item) {

  final Editor editor = context.getEditor();
  if ("returns".equals(item.getLookupString())) {
   EditorModificationUtil.insertStringAtCaret(editor, " ");

   context.setLaterRunnable(() -> new CodeCompletionHandlerBase(CompletionType.BASIC).invokeCompletion(context.getProject(), editor, 1));
  }
 }
}

 @Override
 public void handleInsert(@NotNull final InsertionContext context, @NotNull final LookupElement item) {
  // fixme this is bad check for auto-inserting, i belive
  if (context.getCompletionChar() != '\u0000') {
   context.setLaterRunnable(() -> {
    Editor editor = context.getEditor();
    new CodeCompletionHandlerBase(CompletionType.BASIC).invokeCompletion(context.getProject(), editor, 1);
   });
  }
 }
}

  @Override
  public void run() {
    //当前文件是否最新，没有未提交的
    if (PsiDocumentManager.getInstance(project).isCommitted(editor.getDocument())) {
      //唤醒代码自动补全 ， CompletionContributor
      new CodeCompletionHandlerBase(CompletionType.BASIC).invokeCompletion(project, editor, 1);
    }
  }
});