/* 直接拨打电话 */
  Intent callIntent = new Intent(Intent.ACTION_CALL,Uri.parse("tel:12345678"));
  startActivity(callIntent);

权限:<uses-permission android:name="android.permission.CALL_PHONE"/>

/* 直接发送邮件 */
  Intent sendEmailIntent = new Intent(Intent.ACTION_SEND);
  sendEmailIntent.putExtra(Intent.EXTRA_EMAIL, "目标邮件地址");
  sendEmailIntent.putExtra(Intent.EXTRA_SUBJECT, "目标邮件标题");
  sendEmailIntent.putExtra(Intent.EXTRA_TEXT, "目标邮件内容");
  sendEmailIntent.setType("text/plain"); //纯文本
  startActivity(Intent.createChooser(sendEmailIntent, "选择发送消息的客户端"));或startActivity(sendEmailIntent);

/* 直接发送短信 */

Uri smsToUri = Uri.parse("smsto:10000");
Intent intent = new Intent(Intent.ACTION_SENDTO, smsToUri);
intent.putExtra("sms_body", smsBody);  //参数名固定位sms_body
startActivity(intent);

权限:<uses-permission android:name="android.permission.READ_SMS">