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我无法从单独的类文件中的异步任务中将数据返回到我的主要活动中。

这是我的主要活动：

public class Main extends Activity {
EditText searchOne;
EditText searchTwo;

Button findMovies;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.totlayout);

    //set the UI elements
    searchOne = (EditText) findViewById(R.id.searchOne);
    searchTwo = (EditText) findViewById(R.id.searchTwo);

    findMovies = (Button) findViewById(R.id.findMovies);


}
public void displayResults(View view){
    //do something in response to button
    Intent intent = new Intent(this, DisplayResultsActivity.class);

    //make person search url1
    final StringBuilder personSearchURLOne = new StringBuilder(getName.getName1(searchOne)); 
    final String searchURLOne = personSearchURLOne.toString();
    Log.d("searchurlone", searchURLOne.toString());

    //make person search url2
    final StringBuilder personSearchURLTwo = new StringBuilder(getName.getName2(searchTwo));
    final String searchURLTwo = personSearchURLTwo.toString();

    //get ID 1 this needs to get data back from asynctask in the type string to be passed to buildCreditURL
    new getFirstID().execute(searchURLOne);

    //get ID 2
    new getFirstID().execute(searchURLTwo);

    //make credit search url1
    final StringBuilder creditURLOne = new StringBuilder(buildCreditURL.getCreditURLOne(firstID));

这是包含我的 AsyncTask 的单独类文件：

package com.tot.tipofthetongue;

import android.os.AsyncTask;

import android.util.Log;





import org.json.JSONArray;
import org.json.JSONException;

import org.json.JSONObject;

public class getFirstID extends AsyncTask<String, Void, String> {

public static String TAG_ID = "id";
public static String TAG_RESULTS = "results";


String personOne = null;
static String firstID = null;


@Override
protected String doInBackground(String... personSearchURLOne) {
    Log.d("personSearchURLOne in getFirstID containts", personSearchURLOne[0]);

    JSONArray results = null;

    JSONParser jParser = new JSONParser();

    JSONObject jSon = jParser.doInBackground(personSearchURLOne[0]);

    try{
        results = jSon.getJSONArray(TAG_RESULTS);

        for(int i = 0; i < results.length(); i++){
            JSONObject r = results.getJSONObject(i);
            firstID = r.getString(TAG_ID);

        }


    }
    catch(JSONException e){
        Log.e("Error", e.toString());
    }
            /need this value as string to be passed back to the main activity
    return firstID;


}




}

如何将 firstID 作为字符串输出到我的主要活动中，以便可以在属于另一个单独的类文件的另一个方法中使用它。

更新的 getFirstID：

package com.tot.tipofthetongue;


import android.os.AsyncTask;

import android.util.Log;





import org.json.JSONArray;
import org.json.JSONException;

import org.json.JSONObject;

 public class getFirstID extends AsyncTask<String, Void, String> {

public static String TAG_ID = "id";
public static String TAG_RESULTS = "results";


String personOne = null;
static String firstID = null;


@Override
protected String doInBackground(String... personSearchURLOne) {

    Log.d("personSearchURLOne in getFirstID containts", personSearchURLOne[0]);

    JSONArray results = null;

    JSONParser jParser = new JSONParser();

    JSONObject jSon = jParser.doInBackground(personSearchURLOne[0]);

    try{
        results = jSon.getJSONArray(TAG_RESULTS);

        for(int i = 0; i < results.length(); i++){
            JSONObject r = results.getJSONObject(i);
            firstID = r.getString(TAG_ID);

        }


    }
    catch(JSONException e){
        Log.e("Error", e.toString());
    }
    return firstID;


}
@Override
public void onPostExecute(String firstID){

}




}
4

3 回答 3

2

覆盖类中的onPostExecute(String result)方法getFirstID：

@Override protected void onPostExecute(String result) {
    // Invoke method on Main activity or do other action.
}

该方法由 UI 线程执行，可以更新视图。您可以通过在构造函数中将其MainActivity设置在类的字段中来添加对 的引用。getFirstID

希望能帮助到你！

于 2012-09-16T19:06:14.787 回答
2

一个非常简单的方法是这样做。

public class getFirstID extends AsyncTask<String, Void, Pair<String, String>> {
    public static interface MyAsyncCallback {
        /**
         * Called when the AsyncTask is finished processing the url.
         * @param url the url that the firstId was from
         * @param firstId the id that was parsed out of the json object
         */
        public void setFirstId(String url, String firstId);
    }

    private final MyAsyncCallback mCallback;

    public getFirstID(MyAsyncCallback callback) {
       mCallback = callback;
    }

   public Pair<String,String> doInBackground(String... params) {
       String firstID = parseJsonForID(params); // I am not going to copy your alg into here.
       return Pair.create(params[0], firstId);
   }


   public void onPostExecute(Pair<String,String> urlAndFirstId) {
     mCallback.setFirstId(urlAndFirstId.first, urlAndFirstId.second);
   }
}

public class Main extends Activity implements MyAsyncCallback {
  ....

 public void setFirstId(String url, String firstID) {
      // Example
      Intent intent = new Intent(this, OtherActivity.class);
      intent.putExtra("firstId", firstId);
      intent.putExtra("url", url);
      startActivity(intent);
 }
}
于 2012-09-16T19:06:58.547 回答
1

您可以使用意图将内容发送到另一个活动。

Intent intent = new Intent(this, YourActivity.class);
intent.putExtra("name", string);

在这里阅读

或者你可以把你的 AsyncTask 类放在你的活动类中。

public class Main extends Activity {

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.get_data);


}

private class Download extends AsyncTask <Void, Void, String> {

    protected String doInBackground(Void...params) {

    }

    @Override
    protected void onPostExecute(String result) {

    }

    @Override
    protected void onPreExecute() {

    }

}

}
于 2012-09-16T19:05:55.553 回答