HarmonyOS 鸿蒙Next PasteButton相关

实现的大致思路为，先在复制后使用systemPasteboard.hasData判断是否剪切板有数据，并用bool型状态变量记录，然后使用这个状态变量决定是否需要创建pasteButton控件。基于gitee仓库demo，将index文件中复制按钮部分代码修改如下：

import { BusinessError, pasteboard } from '@kit.BasicServicesKit';
import { unifiedDataChannel } from '@kit.ArkData';
import { CommonConstants } from '../common/CommonConstants';
import Logger from '../common/Logger';

@Entry
@Component
struct Index {
  @State copyText: string = '';
  @State text: string = '';
  @State pasteBoardData: boolean = false;

  build() {
    Column() {
      Text($r('app.string.title'))
        .fontSize($r('app.float.title_font_size'))
        .fontWeight(FontWeight.Bold)
        .height($r('app.float.title_height'))
        .margin({
          top: $r('app.float.title_margin'),
          left: $r('app.float.title_left'),
          bottom: $r('app.float.title_margin')
        })
      Column() {
        TextArea({ placeholder: $r('app.string.input_tip'), text: this.copyText })
          .width(CommonConstants.FULL_PERCENT)
          .height(CommonConstants.TEXTAREA_HEIGHT)
          .onChange((value: string) => {
            this.copyText = value;
          })

        TextArea({ placeholder: $r('app.string.result_tip'), text: this.text })
          .width(CommonConstants.FULL_PERCENT)
          .height(CommonConstants.TEXTAREA_HEIGHT)
          .onChange((value: string) => {
            this.text = value;
          })
          .margin({
            top: $r('app.float.space'),
            bottom: $r('app.float.space')
          })

        Column() {
          if(this.pasteBoardData) {
            PasteButton()
              .width(CommonConstants.FULL_PERCENT)
              .height($r('app.float.button_height'))
              .onClick((_event: ClickEvent, result: PasteButtonOnClickResult) => {
                if (result === PasteButtonOnClickResult.SUCCESS) {
                  pasteboard.getSystemPasteboard().getData((err: BusinessError, pasteData: pasteboard.PasteData) => {
                    if (err && err.code !== 0) {
                      Logger.error('Get system pasteboard error:' + JSON.stringify(err));
                    } else {
                      this.text = pasteData.getPrimaryText();
                    }
                  })
                }
              })
          }

          Button($r('app.string.copy'))
            .width(CommonConstants.FULL_PERCENT)
            .height($r('app.float.button_height'))
            .margin({
              top: $r('app.float.button_space')
            })
            .onClick(() => {
              let plainTextData = new unifiedDataChannel.UnifiedData();
              let plainText = new unifiedDataChannel.PlainText();
              plainText.details = {
                key: 'delayPlaintext',
                value: this.copyText
              };
              plainText.textContent = this.copyText;
              plainText.abstract = 'delayTextContent';
              plainTextData.addRecord(plainText);
              let systemPasteboard: pasteboard.SystemPasteboard = pasteboard.getSystemPasteboard();
              systemPasteboard.setUnifiedData(plainTextData);
              systemPasteboard.hasData((err: BusinessError, data: boolean) => {
                if (err) {
                  console.error(`Failed to check the PasteData. Cause: ${err.message}`);
                  this.pasteBoardData = false;
                  return;
                }
                this.pasteBoardData = data;
                console.info(`Succeeded in checking the PasteData. Data: ${data}`);
              });
            })
        }
      }
      .justifyContent(FlexAlign.SpaceBetween)
      .layoutWeight(1)
      .padding({
        left: $r('app.float.column_side_padding'),
        right: $r('app.float.column_side_padding')
      })
    }
    .alignItems(HorizontalAlign.Start)
    .height(CommonConstants.FULL_PERCENT)
    .width(CommonConstants.FULL_PERCENT)
    .padding({
      bottom: $r('app.float.column_side_padding')
    })
  }
}

参考demo链接：https://gitee.com/harmonyos_samples/pasteboard