Question

apears的错误是android.os.NetworkOnMainThreadException，这与runUithread有关，但我不知道如何更改它。我已经做了asynctask我不明白。请帮帮我。

 /**
 * Background Async Task to Get complete product details
 * */
class GetProductDetails extends AsyncTask<String, String, String> {

    /**
     * Before starting background thread Show Progress Dialog
     * */
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        pDialog = new ProgressDialog(EditProductActivity.this);
        pDialog.setMessage("Loading product details. Please wait...");
        pDialog.setIndeterminate(false);
        pDialog.setCancelable(true);
        pDialog.show();
    }

    /**
     * Getting product details in background thread
     * */
    protected String doInBackground(String... params) {

        // updating UI from Background Thread
        runOnUiThread(new Runnable() {
            public void run() {
                // Check for success tag
                int success;
                try {
                    // Building Parameters
                    List<NameValuePair> params = new ArrayList<NameValuePair>();
                    params.add(new BasicNameValuePair("id", id2));

                    // getting product details by making HTTP request
                    // Note that product details url will use GET request
                    JSONObject json = jParser.makeHttpRequest(
                            url_product_detials, "GET", params);

                    // check your log for json response
                    Log.d("Single Product Details", json.toString());

                    // json success tag
                    success = json.getInt(TAG_SUCCESS);
                    if (success == 1) {
                        // successfully received product details
                        JSONArray productObj = json
                                .getJSONArray(TAG_PRODUCT); // JSON Array

                        // get first product object from JSON Array
                        JSONObject product = productObj.getJSONObject(0);

                        // product with this pid found
                        // Edit Text
                        txtdata1 = (EditText) findViewById(R.id.inputdt_ini);
                        txtdata2 = (EditText) findViewById(R.id.inputdt_fim);
                        txtDesc = (EditText) findViewById(R.id.inputDesc);

                        // display product data in EditText
                        txtdata1.setText(product.getString(TAG_DATA1));
                        txtdata2.setText(product.getString(TAG_DATA2));
                        txtDesc.setText(product.getString(TAG_DESCRICAO));

                    }else{
                        // product with pid not found
                    }
                } catch (JSONException e) {
                    e.printStackTrace();
                }
            }
        });

        return null;
    }

    /**
     * After completing background task Dismiss the progress dialog
     * **/
    protected void onPostExecute(String file_url) {
        // dismiss the dialog once got all details
        pDialog.dismiss();
    }
}

Answer 1

您必须在后台线程中执行网络操作，而不是UI线程，因为您正在执行runOnUiThread。因此，网络操作必须与对UI视图进行更改分开。

而是执行以下操作（一种方法）：

删除runOnUiThread
将您的AsyncTask更改为AsyncTask<String, String, JSONObject>
在product

doInBackground

在onPostExecute中，您可以使用product

所以基本上这可以让您的网络操作全部在后台线程中完成，一旦完成，它将返回product到onPostExecute以供您显示。

您的代码示例（没有测试，但是为您提供了一般性的想法，并且没有包含onPreExecute，因为它与问题无关）：

/**
 * Background Async Task to Get complete product details
 */
class GetProductDetails extends AsyncTask<String, String, JSONObject> {

    /**
     * Getting product details in background thread
     */
    protected JSONObject doInBackground(String... params) {
        // Check for success tag
        int success;
        try {
            // Building Parameters
            List<NameValuePair> params = new ArrayList<NameValuePair>();
            params.add(new BasicNameValuePair("id", id2));

            // getting product details by making HTTP request
            // Note that product details url will use GET request
            JSONObject json = jParser.makeHttpRequest(
                    url_product_detials, "GET", params);

            // check your log for json response
            Log.d("Single Product Details", json.toString());

            // json success tag
            success = json.getInt(TAG_SUCCESS);
            if (success == 1) {
                // successfully received product details
                JSONArray productObj = json
                        .getJSONArray(TAG_PRODUCT); // JSON Array

                // get first product object from JSON Array
                JSONObject product = productObj.getJSONObject(0);

                // instead return your product to onPostExecute
                return product;
            } else {
                // product with pid not found
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }

        return null;
    }

    /**
     * After completing background task Dismiss the progress dialog
     * *
     */
    protected void onPostExecute(JSONObject product) {
        if (product != null) {
            // product with this pid found
            // Edit Text
            txtdata1 = (EditText) findViewById(R.id.inputdt_ini);
            txtdata2 = (EditText) findViewById(R.id.inputdt_fim);
            txtDesc = (EditText) findViewById(R.id.inputDesc);

            // display product data in EditText
            txtdata1.setText(product.getString(TAG_DATA1));
            txtdata2.setText(product.getString(TAG_DATA2));
            txtDesc.setText(product.getString(TAG_DESCRICAO));
        }

        // dismiss the dialog once got all details
        pDialog.dismiss();
    }
}

Answer 2

你是如此接近......在你致电JSONObject之前，做所有的事情来获取你的数据（也就是创建onUiThread()等...）你应该做的唯一的事情在onUiThread()进行操作应该在文本视图上调用setText()。

Asynctask线程错误

2 个答案: