Android代码错误

可能重复：

此处给出了发生错误的程序代码-

 package com.example.annapurna;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.NavUtils;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import java.util.ArrayList;
import java.util.List;

import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONException;
import org.json.JSONObject;

import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.util.Log;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class DisplayContri extends Activity {
    // Progress Dialog
        private ProgressDialog pDialog;

        JSONParser jsonParser = new JSONParser();
        EditText editText1;
        //EditText  text2;
       //EditText  text3;

        // url to create new product
        private static String url_create_product = "http://10.0.2.2/annapurna_connect/userold.php";

        // JSON Node names
        private static final String TAG_SUCCESS = "success";


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


        //Edit text
        editText1 = (EditText) findViewById(R.id.editText1);
        //text2 = (EditText) findViewById(R.id.editText2);
        //text3 = (EditText) findViewById(R.id.editText3);

        //Create Button
        Button button1 = (Button) findViewById(R.id.button1);

        //button click event
        button1.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // Creating new Contribution entry in background thread
                new CreateContribution().execute("");

            }
        });
    }


    /**
     * Background Async Task to Create new product
     * */
    class CreateContribution extends AsyncTask<String, String, String> {

        /**
         * Before starting background thread Show Progress Dialog
         * */
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            pDialog = new ProgressDialog(DisplayContri.this);
            pDialog.setMessage("Creating Product..");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(true);
            pDialog.show();

        }

        /**
         * Creating product
         * */
        protected String doInBackground(String... args) 
        {

            String name = editText1.getText().toString();
            //String age = (text2.getText().toString());
            //String id = (text3.getText().toString());
            Toast toast2=Toast.makeText(getApplicationContext(), "Error2", Toast.LENGTH_LONG);//This is where the error shows  
             toast2.show(); 
            // Building Parameters
            List<NameValuePair> params = new ArrayList<NameValuePair>();
            params.add(new BasicNameValuePair("name", name));
            //params.add(new BasicNameValuePair("age", age));
            //params.add(new BasicNameValuePair("id", id));

            // getting JSON Object
            // Note that create product url accepts POST method
            JSONObject json = jsonParser.makeHttpRequest(url_create_product,
                    "POST", params);

            // check log cat fro response
            Log.d("Create Response", json.toString());

            // check for success tag
            try {
                int success = json.getInt(TAG_SUCCESS);

                if (success == 1) {
                    // successfully created product
                    Intent i = new Intent(getApplicationContext(), Annapurna.class);
                    startActivity(i);

                    // closing this screen
                    finish();
                } else {
                    // failed to create product
                }
            } 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 done
            pDialog.dismiss();
        }

    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_display_contri, menu);
        return true;
    }


    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case android.R.id.home:
                NavUtils.navigateUpFromSameTask(this);
                return true;
        }
        return super.onOptionsItemSelected(item);
    }
    public void contributor(View view) {
        Intent intent = new Intent(this, Contributor.class);

        startActivity(intent);
    }

   }

有一个用于连接的Jsonparsor.java类。

---

在上面的代码中，doInBackground方法没有执行，我通过添加toast测试了应用程序，发现它没有进入doInBackground方法并一直执行到preexecute的最后一个末尾。请检查是否在主线程以外的线程上创建AsyncTask

您正试图从异步任务的后台更新UI

这是办不到的

---

如果您有任何Toast或任何其他更新，请确保将其从doInBackground删除到UI

任何背景，比如什么时候，什么地方发生的？代码示例？如果您正在处理任何邮件应用程序，以便检查您从日志发送的附件路径，听起来您正试图显示对话框等，或者从后台线程更改布局，如doInBackground。非常感谢您…我在过去三周中一直使用相同的代码。但现在终于完成了。没有问题，我的朋友。。我很高兴它帮助了你。现在，单击此答案左侧的勾号接受此答案如何：

 package com.example.annapurna;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.NavUtils;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import java.util.ArrayList;
import java.util.List;

import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONException;
import org.json.JSONObject;

import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.util.Log;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class DisplayContri extends Activity {
    // Progress Dialog
        private ProgressDialog pDialog;

        JSONParser jsonParser = new JSONParser();
        EditText editText1;
        //EditText  text2;
       //EditText  text3;

        // url to create new product
        private static String url_create_product = "http://10.0.2.2/annapurna_connect/userold.php";

        // JSON Node names
        private static final String TAG_SUCCESS = "success";


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


        //Edit text
        editText1 = (EditText) findViewById(R.id.editText1);
        //text2 = (EditText) findViewById(R.id.editText2);
        //text3 = (EditText) findViewById(R.id.editText3);

        //Create Button
        Button button1 = (Button) findViewById(R.id.button1);

        //button click event
        button1.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // Creating new Contribution entry in background thread
                new CreateContribution().execute("");

            }
        });
    }


    /**
     * Background Async Task to Create new product
     * */
    class CreateContribution extends AsyncTask<String, String, String> {

        /**
         * Before starting background thread Show Progress Dialog
         * */
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            pDialog = new ProgressDialog(DisplayContri.this);
            pDialog.setMessage("Creating Product..");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(true);
            pDialog.show();

        }

        /**
         * Creating product
         * */
        protected String doInBackground(String... args) 
        {

            String name = editText1.getText().toString();
            //String age = (text2.getText().toString());
            //String id = (text3.getText().toString());
            Toast toast2=Toast.makeText(getApplicationContext(), "Error2", Toast.LENGTH_LONG);//This is where the error shows  
             toast2.show(); 
            // Building Parameters
            List<NameValuePair> params = new ArrayList<NameValuePair>();
            params.add(new BasicNameValuePair("name", name));
            //params.add(new BasicNameValuePair("age", age));
            //params.add(new BasicNameValuePair("id", id));

            // getting JSON Object
            // Note that create product url accepts POST method
            JSONObject json = jsonParser.makeHttpRequest(url_create_product,
                    "POST", params);

            // check log cat fro response
            Log.d("Create Response", json.toString());

            // check for success tag
            try {
                int success = json.getInt(TAG_SUCCESS);

                if (success == 1) {
                    // successfully created product
                    Intent i = new Intent(getApplicationContext(), Annapurna.class);
                    startActivity(i);

                    // closing this screen
                    finish();
                } else {
                    // failed to create product
                }
            } 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 done
            pDialog.dismiss();
        }

    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_display_contri, menu);
        return true;
    }


    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case android.R.id.home:
                NavUtils.navigateUpFromSameTask(this);
                return true;
        }
        return super.onOptionsItemSelected(item);
    }
    public void contributor(View view) {
        Intent intent = new Intent(this, Contributor.class);

        startActivity(intent);
    }

   }