HarmonyOS 鸿蒙Next：打开系统邮箱并且展示邮件地址

可以通过拼接uri传递收件人，抄送人，内容等参数，关键代码参考如下

mail({ subject= '', recipients=[], body='', ccRecipients=[], bccRecipients=[] }: mainOptions, callback: Function) {
 let mailUri: string = '';
 mailUri += recipients?.join(',') || '';
 mailUri += '?cc=' + ccRecipients?.join(',') || '';
 mailUri += '&bcc=' + bccRecipients?.join(',') || '';
 mailUri += '&subject=' + subject;
 mailUri += '&body=' + body;
 Logger.info(TAG + 'mailUri ', mailUri, 'ccRecipients:' + ccRecipients, 'bccRecipients:' + bccRecipients);
 this.startEmailApp(mailUri, callback);
}


startEmailApp = (mailUri, callback) => {
 let want: Want = {
   bundleName: 'com.huawei.hmos.email',
   abilityName: 'EntryAbility',
   moduleName: 'entry',
   uri: 'mailto:' + mailUri,
   action: 'ohos.want.action.viewData',
 };
 Logger.info(TAG + 'want ', JSON.stringify(want));

 try {
   this.ctx.uiAbilityContext.startAbility(want)
     .then(() => {
       Logger.info(TAG, 'startAbility success');
     })
     .catch((err: BusinessError) => {
       Logger.info(TAG, 'startAbility error.', err.message);
       callback(err.message);
     })
 } catch (e) {
   callback(e);
   Logger.info(TAG + 'error:', e);
 }
}