Android异常NetworkonMainThreadException(已经使用了Asynctask，但仍然错误)

Question

我正在构建一个简单的Android应用程序，但我一直在获得此例外NetworkOnMainThreadException。我已经对此进行了很多研究，我知道在Android3.0（Honeycomb）OS及更高版本上，它更严格，应该使用Asynctask（在后台线程上），并且我已经完成了我发现的所有事情，但仍然得到此例外，有人可以指导如何解决此问题吗？

editproductactivity.java：

package com.example.test;
import java.util.ArrayList;
import java.util.List;
import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
public class EditProductActivity extends Activity {
    EditText txtName;
    EditText txtPrice;
    EditText txtDesc;
    EditText txtCreatedAt;
    Button btnSave;
    Button btnDelete;
    String pid;
    //progress Dialog
    private ProgressDialog pDialog;
    //JSON parser class
    JSONParser jsonParser = new JSONParser();
    //single product url
    private static final String url_product_details = "http://api.kerjaapa.com/android_connect/get_product_details.php";
    //url to update product
    private static final String url_update_product = "http://api.kerjaapa.com/android_connect/update_product.php";
    //url to delete product
    private static final String url_delete_product = "http://api.kerjaapa.com/android_connect/delete_product.php";
    //JSON Node names
    private static final String TAG_SUCCESS = "success";
    private static final String TAG_PRODUCT = "product";
    private static final String TAG_PID = "pid";
    private static final String TAG_NAME = "name";
    private static final String TAG_PRICE = "price";
    private static final String TAG_DESCRIPTION = "description";
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.edit_product);
        //save button
        btnSave = (Button) findViewById(R.id.btnSave);
        btnDelete = (Button) findViewById(R.id.btnDelete);
        //getting product details from intent
        Intent i = getIntent();
        //getting product id(pid) from intent
        pid = i.getStringExtra(TAG_PID);
        //getting complete product details in background thread
        new GetProductDetails().execute();
        //save button click event
        btnSave.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View arg0) {
                //starting background task to update product
                new SaveProductDetails().execute();
            }
        });
        //Delete button click event
        btnDelete.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View arg0) {
                //deleting product in background thread
                new DeleteProduct().execute();
            }
        });
    }
    //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("pid", pid));
                        //getting product details by making HTTP request
                        //Note that product details url will use GET request
                        JSONObject json = jsonParser.makeHttpRequest(
                            url_product_details, "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
                            txtName = (EditText) findViewById(R.id.inputName);
                            txtPrice = (EditText) findViewById(R.id.inputPrice);
                            txtDesc = (EditText) findViewById(R.id.inputDesc);
                            //display product data in editText
                            txtName.setText(product.getString(TAG_NAME));
                            txtPrice.setText(product.getString(TAG_PRICE));
                            txtDesc.setText(product.getString(TAG_DESCRIPTION));
                        } 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();
        }
    }
    //Background Async Task to Save product details
    class SaveProductDetails extends AsyncTask<String, String, String> {
        //Before starting background thread, show dialog
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            pDialog = new ProgressDialog(EditProductActivity.this);
            pDialog.setMessage("Saving product ...");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(true);
            pDialog.show();
        }
        //Saving product
        protected String doInBackground(String... args) {
            //getting updated data from EditTexts
            String name = txtName.getText().toString();
            String price = txtPrice.getText().toString();
            String description = txtDesc.getText().toString();
            //Building parameters
            List<NameValuePair> params = new ArrayList<NameValuePair>();
            params.add(new BasicNameValuePair(TAG_PID, pid));
            params.add(new BasicNameValuePair(TAG_NAME, name));
            params.add(new BasicNameValuePair(TAG_PRICE, price));
            params.add(new BasicNameValuePair(TAG_DESCRIPTION, description));
            //sending modified data through http request
            //Notice that update product url accepts POST method
            JSONObject json = jsonParser.makeHttpRequest(url_update_product, 
                "POST", params);
            //check json success tag
            try {
                int success = json.getInt(TAG_SUCCESS);
                if (success == 1) {
                    //successfully updated
                    Intent i = getIntent();
                    //send result code 100 to notify about product update
                    setResult(100, i);
                    finish();
                } else {
                    //failed to update product
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }
            return null;
        }
        //After completing background task, dismiss dialog
        protected void onPostExecute(String file_url) {
            //dismiss dialog
            pDialog.dismiss();
        }
    }
    //Background async task to delete product
    class DeleteProduct extends AsyncTask<String, String, String> {
        //Before starting, show progress dialog
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            pDialog = new ProgressDialog(EditProductActivity.this);
            pDialog.setMessage("Deleting Product...");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(true);
            pDialog.show();
        }
        //Deleting product
        protected String doInBackground(String... args) {

            //check for success tag
            int success;
            try {
                //Building parameters
                List<NameValuePair> params = new ArrayList<NameValuePair>();
                params.add(new BasicNameValuePair("pid", pid));
                //getting product details by making HTTP request
                JSONObject json = jsonParser.makeHttpRequest(
                    url_delete_product, "POST", params);
                //check your log for json response
                Log.d("Delete product", json.toString());
                //json success tag
                success = json.getInt(TAG_SUCCESS);
                if (success == 1) {
                    //product successfully deleted
                    //notify previous activity by sending code 100
                    Intent i = getIntent();
                    //send result code 100 to notify about product deletion
                    setResult(100, i);
                    finish();
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }
            return null;
        }
        //After completing background task dismiss dialog
        protected void onPostExecute(String file_url) {
            //dismiss dialog once finish
            pDialog.dismiss();
        }
    }
}

和布局xml：

edit_product.xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >
    <!-- Name Label -->
    <TextView android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Product Name"
        android:paddingLeft="10dip"
        android:paddingRight="10dip"
        android:paddingTop="10dip"
        android:textSize="17dip" />
    <!-- Input Name -->
    <EditText android:id="@+id/inputName"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_margin="5dip"
        android:layout_marginBottom="15dip"
        android:singleLine="true" />
    <!-- Price Label -->
    <TextView android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Price"
        android:paddingLeft="10dip"
        android:paddingRight="10dip"
        android:paddingTop="10dip"
        android:textSize="17dip" />
    <!-- Input Price -->
    <EditText android:id="@+id/inputPrice"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_margin="5dip"
        android:layout_marginBottom="15dip"
        android:singleLine="true" 
        android:inputType="numberDecimal" />
    <!-- Description Label -->
    <TextView android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Description"
        android:paddingLeft="10dip"
        android:paddingRight="10dip"
        android:paddingTop="10dip"
        android:textSize="17dip" />
    <!-- Input Description -->
    <EditText android:id="@+id/inputDesc"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_margin="5dip"
        android:layout_marginBottom="15dip"
        android:lines="4"
        android:gravity="top" />
    <LinearLayout android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">
        <!-- Button Update Product -->
        <Button android:id="@+id/btnSave"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:text="Save Changes"
            android:layout_weight="1" />
        <!-- Button Delete Product -->
        <Button android:id="@+id/btnDelete"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:text="Delete"
            android:layout_weight="1" />
    </LinearLayout>

</LinearLayout>

这是调试错误堆栈：

在
defaultrequestdirector.execute（httphost，httprequest，httpcontext）行：531
defaulthttpclient（apptracthtpclient）.ececute（httphost，httprequest，httpcontext）行：555 defaulthttpclient（apptracthtpclient）.execute（httpurirequest，httpcontext）行：487
defaulthttpclient（apptracthttpclient）.ececute（httpurirequest）行：465 jsonparser.makehttprequest（字符串，字符串，列表）行：61
editproductivity $ getProductDetails $ 1.run（）线：120 Handler.HandleCallback（消息）行：733
Handler.disPatchMessage（消息）行：95
looper.loop（）线：136 ActivityThread.main（String []）行：5017
method.invokenative（对象，对象[]，class，class []，class，int，boolean）行：不可用[本机方法]
method.invoke（对象，对象...）行：515
zygoteinit $ methodandargscaller.run（）行：779
zygoteinit.main（string []）行：595 nativestart.main（string []）行：不可用[本机方法]

我认为我已经遵循了使用asynctask，使用onpreexecute（），onpostexecute（）在后台执行任务的规则。对不起，我是新手，对任何帮助都非常感谢。提前。

Answer 1

我认为我已经遵循了使用异步的规则，执行任务 在背景上使用onpreexecute（），onpostexecute（）。

并不是因为在您的doInBackground中您在UI线程上执行HTTP请求：

runOnUiThread(new Runnable() {
                public void run() {

完全失败了使用异步任务的目的。

因此，请删除runOnUiThread，在后台进行请求，完成任务后使用onPostExecute来更新您的字段。

Answer 2

您的doinbackground应该运行网络操作并将结果发布到OnPostExecute，您可以在其中更新UI。

Answer 3

您的doinbackground方法正在调用runonuithread，这是胡说八道。

您应该在doinbackground上进行背景工作，然后在onpostexecute中执行UI工作，例如：

package com.example.test;
import java.util.ArrayList;
import java.util.List;
import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
public class EditProductActivity extends Activity {
    EditText txtName;
    EditText txtPrice;
    EditText txtDesc;
    EditText txtCreatedAt;
    Button btnSave;
    Button btnDelete;
    String pid;
    //progress Dialog
    private ProgressDialog pDialog;
    //JSON parser class
    JSONParser jsonParser = new JSONParser();
    //single product url
    private static final String url_product_details = "http://api.kerjaapa.com/android_connect/get_product_details.php";
    //url to update product
    private static final String url_update_product = "http://api.kerjaapa.com/android_connect/update_product.php";
    //url to delete product
    private static final String url_delete_product = "http://api.kerjaapa.com/android_connect/delete_product.php";
    //JSON Node names
    private static final String TAG_SUCCESS = "success";
    private static final String TAG_PRODUCT = "product";
    private static final String TAG_PID = "pid";
    private static final String TAG_NAME = "name";
    private static final String TAG_PRICE = "price";
    private static final String TAG_DESCRIPTION = "description";
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.edit_product);
        //save button
        btnSave = (Button) findViewById(R.id.btnSave);
        btnDelete = (Button) findViewById(R.id.btnDelete);
        //getting product details from intent
        Intent i = getIntent();
        //getting product id(pid) from intent
        pid = i.getStringExtra(TAG_PID);
        //getting complete product details in background thread
        new GetProductDetails().execute();
        //save button click event
        btnSave.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View arg0) {
                //starting background task to update product
                new SaveProductDetails().execute();
            }
        });
        //Delete button click event
        btnDelete.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View arg0) {
                //deleting product in background thread
                new DeleteProduct().execute();
            }
        });
    }
    //Background Async Task to Get Complete Product Details
    class GetProductDetails extends AsyncTask<String, String, Integer> {
        //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) {
                    //Check for success tag
                    int success = 0;
                    try {
                        //Building Parameters
                        List<NameValuePair> params = new ArrayList<NameValuePair>();
                        params.add(new BasicNameValuePair("pid", pid));
                        //getting product details by making HTTP request
                        //Note that product details url will use GET request
                        JSONObject json = jsonParser.makeHttpRequest(
                            url_product_details, "GET", params);
                        //check your log for json response
                        Log.d("Single Product Details", json.toString());
                        //json success tag
                        success = json.getInt(TAG_SUCCESS);
                    } catch (JSONException e) {
                        e.printStackTrace();
                        }
                    }
            return success;
        }
        //After completing background task dismiss the progress dialog
        protected void onPostExecute(Integer 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
                    txtName = (EditText) findViewById(R.id.inputName);
                    txtPrice = (EditText) findViewById(R.id.inputPrice);
                    txtDesc = (EditText) findViewById(R.id.inputDesc);
                    //display product data in editText
                    txtName.setText(product.getString(TAG_NAME));
                    txtPrice.setText(product.getString(TAG_PRICE));
                    txtDesc.setText(product.getString(TAG_DESCRIPTION));
                } else {
                    //product with pid not found
                }
            //dismiss the dialog once got all details
            pDialog.dismiss();
        }
    }
    //Background Async Task to Save product details
    class SaveProductDetails extends AsyncTask<String, String, String> {
        //Before starting background thread, show dialog
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            pDialog = new ProgressDialog(EditProductActivity.this);
            pDialog.setMessage("Saving product ...");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(true);
            pDialog.show();
        }
        //Saving product
        protected String doInBackground(String... args) {
            //getting updated data from EditTexts
            String name = txtName.getText().toString();
            String price = txtPrice.getText().toString();
            String description = txtDesc.getText().toString();
            //Building parameters
            List<NameValuePair> params = new ArrayList<NameValuePair>();
            params.add(new BasicNameValuePair(TAG_PID, pid));
            params.add(new BasicNameValuePair(TAG_NAME, name));
            params.add(new BasicNameValuePair(TAG_PRICE, price));
            params.add(new BasicNameValuePair(TAG_DESCRIPTION, description));
            //sending modified data through http request
            //Notice that update product url accepts POST method
            JSONObject json = jsonParser.makeHttpRequest(url_update_product, 
                "POST", params);
            //check json success tag
            try {
                int success = json.getInt(TAG_SUCCESS);
                if (success == 1) {
                    //successfully updated
                    Intent i = getIntent();
                    //send result code 100 to notify about product update
                    setResult(100, i);
                    finish();
                } else {
                    //failed to update product
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }
            return null;
        }
        //After completing background task, dismiss dialog
        protected void onPostExecute(String file_url) {
            //dismiss dialog
            pDialog.dismiss();
        }
    }
    //Background async task to delete product
    class DeleteProduct extends AsyncTask<String, String, String> {
        //Before starting, show progress dialog
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            pDialog = new ProgressDialog(EditProductActivity.this);
            pDialog.setMessage("Deleting Product...");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(true);
            pDialog.show();
        }
        //Deleting product
        protected String doInBackground(String... args) {

            //check for success tag
            int success;
            try {
                //Building parameters
                List<NameValuePair> params = new ArrayList<NameValuePair>();
                params.add(new BasicNameValuePair("pid", pid));
                //getting product details by making HTTP request
                JSONObject json = jsonParser.makeHttpRequest(
                    url_delete_product, "POST", params);
                //check your log for json response
                Log.d("Delete product", json.toString());
                //json success tag
                success = json.getInt(TAG_SUCCESS);
                if (success == 1) {
                    //product successfully deleted
                    //notify previous activity by sending code 100
                    Intent i = getIntent();
                    //send result code 100 to notify about product deletion
                    setResult(100, i);
                    finish();
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }
            return null;
        }
        //After completing background task dismiss dialog
        protected void onPostExecute(String file_url) {
            //dismiss dialog once finish
            pDialog.dismiss();
        }
    }
}

Answer 4

doinbackground 不与主UI线程交互，并且您在 doinbackground 中提到了 asyntask 的视图strong>

还删除 runonuithread 从 doinbackground

也将它们放入 onpostexecute 方法

 //product with this pid found
//Edit text
                            txtName = (EditText) findViewById(R.id.inputName);
                            txtPrice = (EditText) findViewById(R.id.inputPrice);
                            txtDesc = (EditText) findViewById(R.id.inputDesc);
                            //display product data in editText
                            txtName.setText(product.getString(TAG_NAME));
                            txtPrice.setText(product.getString(TAG_PRICE));
                            txtDesc.setText(product.getString(TAG_DESCRIPTION));