如何在AsyncTask doInBackground（）中使用同步对象？

Question

我在后台线程中使用synchronized对象时遇到了麻烦。我在样本简介中指定了问题：

1. 我写这样简单的类：

   public class UIThreadClass {
   
      MyObject object;
   
      UIThreadClass() {
         object = new MyObject();
   
         object.doActionOne();
         object.doActionTwo();
     }
   }

2. 现在我的任务是通过将两个方法放到非UI线程来改进代码。我正在使用AsyncTask 对于doActionOne（）

   private static class DoActionOneTask extends AsyncTask<Void, Void, Void> {
   
       private WeakReference<MyObject> wObject;
   
       DoActionOneTask(MyObject object) {
           wObject = new WeakReference<>(object);
       }
   
       @Override
       protected Void doInBackground(Void... voids) {
          if(wObject.get() != null) {
             MyObject myObject = wObject.get();
             myObject.doActionOne();
          }
   
          return null;
       }
   }

   对于doActionTwo（）

   private static class DoActionTwoTask extends AsyncTask<Void, Void, Void> {
   
       private WeakReference<MyObject> wObject;
   
       DoActionOneTask(MyObject object) {
           wObject = new WeakReference<>(object);
       }
   
       @Override
       protected Void doInBackground(Void... voids) {
          if(wObject.get() != null) {
             MyObject myObject = wObject.get();
             myObject.doActionTwo();
          }
   
          return null;
       }
   }

   现在在UI线程中调用它们

   public class UIThreadClass {
   
      MyObject object;
   
      UIThreadClass() {
         object = new MyObject();
   
         new DoActionOneTask(object).execute();
         new DoActionTwoTask(object).execute();
     }
   }

问题是：

使用AsyncTask时 - 如何同步对象以确保在doActionOne（）方法之后总是调用doActionTwo（）？

我尝试在doInBackground（）中使用synchronized（myObject）{myObject.doActionOne（）;}但是系统警告我myObject只是局部变量而且很难保证正确性。

任何人都可以帮我这种情况吗？非常感谢！

Answer 1

你不需要做任何事情。它们将按照Android文档顺序执行

Order of execution
When first introduced, AsyncTasks were executed serially on a single background thread. Starting with DONUT, this was changed to a pool of threads allowing multiple tasks to operate in parallel. Starting with HONEYCOMB, tasks are executed on a single thread to avoid common application errors caused by parallel execution.

If you truly want parallel execution, you can invoke executeOnExecutor(java.util.concurrent.Executor, Object[]) with THREAD_POOL_EXECUTOR.