Question

我创建了一个类DataAdapter，它启动线程以从webservices获取数据。使用

在活动中调用时

DataAdapter.InitData();

我怎么知道两个线程何时完成？

由于七月

public class DataAdapter {

    private final static String URL = "http://www.mywebservice.com";
    private final static String URL_AD = "http://www.mywebservice2.com";

    public void InitData(){

       new GetInitData().execute(URL);
       new GetAd().execute(URL_AD);

    }

    private static class GetInitData extends AsyncTask<String, Integer, JSONObject> {
        protected JSONObject doInBackground(String... urls) {  

            JSONObject json = RestJsonClient.getJSONObject(urls[0]);
            return json;
        }

        protected void onProgressUpdate(Integer... progress) {                
        }

        protected void onPostExecute(JSONObject json) {          

           //process data
        }
    }

    private static class GetAd extends AsyncTask<String, Integer, JSONObject> {
        protected JSONObject doInBackground(String... urls) {  

            JSONObject json = RestJsonClient.getJSONObject(urls[0]);
            return json;
        }

        protected void onProgressUpdate(Integer... progress) {                
        }

        protected void onPostExecute(JSONObject json) {          

           //process data
        }
    }
}

Answer 1

使用此：

public class DataAdapter {

private final String URL = "http://www.mywebservice.com";
private final String URL_AD = "http://www.mywebservice2.com";
private boolean finished = false;

public void InitData(){

   new GetInitData(this).execute(URL);
   new GetAd(this).execute(URL_AD);

}

public void finished(){  
  if(!finished){
   finished = true;
  }else{
   Log.d("TAG","Both have finished"):
  }


private class GetInitData extends AsyncTask<String, Integer, JSONObject> {
    Activity ac = null;
    public GetInitData(Activity ac){
      this.ac=ac;
    }

    protected JSONObject doInBackground(String... urls) { 

        JSONObject json = RestJsonClient.getJSONObject(urls[0]);
        return json;
    }

    protected void onProgressUpdate(Integer... progress) {                
    }

    protected void onPostExecute(JSONObject json) {          

       //process data
       ac.finished();
    }
}

private class GetAd extends AsyncTask<String, Integer, JSONObject> {
   Activity ac = null;
    public GetInitData(Activity ac){
      this.ac=ac;
    }

    protected JSONObject doInBackground(String... urls) {  

        JSONObject json = RestJsonClient.getJSONObject(urls[0]);
        return json;
    }

    protected void onProgressUpdate(Integer... progress) {                
    }

    protected void onPostExecute(JSONObject json) {          

       //process data
       ac.finished();
    }
}

}

Answer 2

向DataAdapter类添加一个synchronized方法，其中每个AsyncTask都在其onPostExecute（）中运行。在此方法中，您设置一个布尔变量，指示第一个作业完成，当第二个AsyncTask调用该方法时，它检查第一个线程是否已经完成。如果两者都已完成，您可以使用自定义代码。

如何知道外部类中的异步任务已完成？

2 个答案: