java - 如何在AsyncTask中获取onPostExecute结果？

Question

我已经使用 AsyncTask 几天了。我的旧代码可以在 API 8 上使用 runOnUIThred 运行，但不能在 >API 18 上运行。我想在 doInBackground() 中使用 JSON 将数据发送到数据库，并在 onPostExecute() 中获取数据。如何将我的代码分成两部分？

class GetProductDetails extends AsyncTask<String, String, Integer> {

    @Override
    protected void onPreExecute() {
       //bla-bla-bla
    }

    protected Integer doInBackground(String... args) {
               int success = 0;
                try {
                    List<NameValuePair> params = new ArrayList<NameValuePair>();
                    params.add(new BasicNameValuePair("pid", pid));

                    JSONObject json = jsonParser.makeHttpRequest(
                            url_product_detials, "GET", params);
                    success = json.getInt(TAG_SUCCESS);

                } catch (Exception e) {
                    e.printStackTrace();
                }

        return success;
    }

    protected void onPostExecute(Integer success) {
          pDialog.dismiss();
          JSONArray productObj = json.getJSONArray(TAG_PRODUCT); 
          JSONObject product = productObj.getJSONObject(0);

          if (success == 1) {

                txtName = (TextView) findViewById(R.id.tvName);
                txtPrice = (TextView) findViewById(R.id.tvPrice);
                txtDesc = (TextView) findViewById(R.id.tvDescription);
                txtCurrent = (TextView) findViewById(R.id.tvCurrent);
                txtTurn = (TextView) findViewById(R.id.tvTurn);

                txtName.setText(product.getString(TAG_NAME));
                txtPrice.setText(product.getString(TAG_PRICE));
                txtDesc.setText(product.getString(TAG_DESCRIPTION));
                txtCurrent.setText(product.getString("current"));
                txtTurn.setText(product.getString("turn"));

          }else{ }
       }
}

Answer 1

您可以让 doInBackground 返回 JSONObject json 并在 onPostExecute 中使用它。

然后要检查是否一切正常，请在 onPostExecute 中进行检查。

类似于:

class GetProductDetails extends AsyncTask<String, String, JSONObject>
{

    @Override
    protected void onPreExecute() {
        //bla-bla-bla
    }

    protected JSONObject doInBackground(String... args) {
        JSONObject json = null;

        try {
            List<NameValuePair> params = new ArrayList<NameValuePair>();
            params.add(new BasicNameValuePair("pid", pid));

            json = jsonParser.makeHttpRequest(
                    url_product_detials, "GET", params);

        } catch (Exception e) {
            e.printStackTrace();
        }

        return json;
    }

    protected void onPostExecute(JSONObject json) {

        pDialog.dismiss();
        if (json == null) return; // check if json is null too! if null something went wrong (handle it, i used return as example)

        int success = json.getInt(TAG_SUCCESS);;

        if (success == 1) {
            JSONArray productObj = json.getJSONArray(TAG_PRODUCT);
        JSONObject product = productObj.getJSONObject(0);
            txtName = (TextView) findViewById(R.id.tvName);
            txtPrice = (TextView) findViewById(R.id.tvPrice);
            txtDesc = (TextView) findViewById(R.id.tvDescription);
            txtCurrent = (TextView) findViewById(R.id.tvCurrent);
            txtTurn = (TextView) findViewById(R.id.tvTurn);

            txtName.setText(product.getString(TAG_NAME));
            txtPrice.setText(product.getString(TAG_PRICE));
            txtDesc.setText(product.getString(TAG_DESCRIPTION));
            txtCurrent.setText(product.getString("current"));
            txtTurn.setText(product.getString("turn"));

        }else{

        }
    }