java - Android匿名asyncTask方法中的返回值

Question

现在在我的应用程序中，我尝试从 url 进行 http 解析，但在此之前我没有携带线程...

我有这样的类和方法:

public class TwitterOAuthHelper {
public String httpQueryToApi(String url) {
        HttpGet get = new HttpGet(url);
        HttpParams params = new BasicHttpParams();
        HttpProtocolParams.setUseExpectContinue(params, false);
        get.setParams(params);
        String response = null;
        try {
            SharedPreferences settings = context.getSharedPreferences("my_app", 0);
            String userKey = settings.getString("user_key", "");
            String userSecret = settings.getString("user_secret", "");
            consumer.setTokenWithSecret(userKey, userSecret);
            consumer.sign(get);
            DefaultHttpClient client = new DefaultHttpClient();
            response = client.execute(get, new BasicResponseHandler());
        } catch (Exception e) {
            displayToast("Failed to get data.");
        }
        return response;
    }

}

现在我尝试将此逻辑移至 asyncTask 中:

String result;
public String httpQueryToApi(String url) {
    new AsyncTask<String,Void,String>(){

        @Override
        protected String doInBackground(String... params) {
            HttpGet get = new HttpGet(String.valueOf(params));
            HttpParams param = new BasicHttpParams();
            HttpProtocolParams.setUseExpectContinue(param, false);
            get.setParams(param);
            String response = null;
            try {
                SharedPreferences settings = context.getSharedPreferences("my_app", 0);
                String userKey = settings.getString("user_key", "");
                String userSecret = settings.getString("user_secret", "");
                consumer.setTokenWithSecret(userKey, userSecret);
                consumer.sign(get);
                DefaultHttpClient client = new DefaultHttpClient();
                response = client.execute(get, new BasicResponseHandler());
            } catch (Exception e) {
                displayToast("Failed to get data.");
            }
            result = response;
            return response;
        }
    }.execute(url);
    return result;
    }

但是我如何将响应结果值返回给方法？

这样做的最佳实践是什么？

Answer 1

将以下方法添加到 asynctask 主体(在 doInBackground 方法下面):

@Override
protected void onPostExecute(String result) {
    // result is your returned value from doInBackground
    // now we are in main ui thread
}

如果你想要回调另一个方法，它应该是接口(interface)

public interface ResultInterface {
     public void resultFromHttp(String result);
}

然后是你的方法

public String httpQueryToApi(String url, final ResultInterface ri){
      //as bove
    @Override
    protected void onPostExecute(String result) {
        if(ri!=null)
            ri.resultFromHttp(result);
    }

}

在您的Activity/Fragment/任何调用httpQueryToApi的地方实现ResultInterface，传递this 作为第二个参数(ri 接口(interface))