Question

我有一个MainActivity和一个AsyncTask类。当我将其称为myTask时，MainActivity效果很好。

但是如何从MainActivity调用myTask的onPostExecute结果。

这是我的第一个问题，如果我错了，我深表歉意。

myTask类

public  class myTask extends AsyncTask<String, Void, String> {
    ProgressDialog mProgressDialog;
    DownloadCallback mDownloadCallback;
    Exception mException;
    Context mContext;
    JSONArray PHPfromArray= null;
    String status="", message="";
    private OkHttpClient client = new OkHttpClient();


    public myTask(Context context, DownloadCallback downloadCallback) {
        mContext = context;
        mDownloadCallback = downloadCallback;

    }

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        mProgressDialog = new ProgressDialog(mContext);
        mProgressDialog.setMessage("Downloading.. ");
        mProgressDialog.show();
    }

    @Override
    protected String doInBackground(String... p) {
        String jsonData = null;

        return null;
    }

    @Override
    protected void onPostExecute(String result) {
        mProgressDialog.dismiss();
        if ( result== null )
        {
            mDownloadCallback.onFailure(mException);
        } else {
            mDownloadCallback.onSuccess(durum);
        }
    }



    public interface DownloadCallback
    {
        void onSuccess(String downloadedString);
        void onFailure(Exception exception);
    }
}

此代码不起作用，如何从MainActivity调用？

   new myTask(this, new myTask() {
            @Override
            public void onSuccess(String downloadedString) {

            }
            @Override
            public void onFailure(Exception exception) {

            }
        });

Answer 1

您可以这样修改myTask：

  ....
  public myTask(Context context){
            mContext = context;
  }//firstly modify constructor

  public void setCallback(DownloadCallback downloadCallback){
        mDownloadCallback = downloadCallback;
  }//add a function
  ...

然后您可以在活动中实现android，如下所示：

public class MainActivity extends AppCompatActivity implements myTask.DownloadCallback {
            ...
            final myTask myTask = new myTask(MainActivity.this);
            myTask.setCallback(MainActivity.this);
            myTask.execute();

            @Override
            public void onSuccess(String downloadedString) {

            }

            @Override
            public void onFailure(Exception exception) {

            }
        }

如何从ASyncTask调用父活动功能完成

1 个答案: