Android＆amp; Azure移动服务查询：如何在查询完成之前暂停代码执行

Question

我需要知道如何暂停代码执行，直到我的移动服务查询完成。我得到一个空指针异常，因为代码试图在查询完成之前访问查询数据。

---Code---
mEmployeeTable.execute(new TableQueryCallback<Employee>() {
 //get employees
 ...
});

//In this activity i attempt to use the info loaded from the query above
//however since the query has not completed i get null pointer exception
startActivity(intent);

Answer 1

只有在收到回调时才需要启动活动，类似于下面的代码：

mEmployeeTable.execute(new TableQueryCallback<Employee>() {
  @Override
  public void onCompleted(List<Employee> employees, int count, Exception exception, ServiceFilterResponse response) {
    if (exception != null) {
      // error happened during query, deal with it appropriately
    } else {
      // store the loaded employees somewhere
      startActivity(intent);
    }
  }
});