我是Android应用程序开发的新手。我有这个源代码，我试图让它工作，我从在线教程中获取它。
我面临的问题是，当我在设备或模拟器上运行此代码时，出现以下错误：
不幸的是，MainScreen已停止
但是我的数据被输入到我在wamp中创建的mysql数据库中。
这是我的代码： 1.AllProductsActivity
package com.example.androidhive;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import org.apache.http.NameValuePair;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.ListActivity;
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.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;
public class AllProductsActivity extends ListActivity {
private ProgressDialog pDialog;
JSONParser jParser = new JSONParser();
ArrayList<HashMap<String, String>> productsList;
private static String url_all_products = "http://10.0.2.2/android_connect/get_all_products.php";
private static final String TAG_SUCCESS = "success";
private static final String TAG_PRODUCTS = "products";
private static final String TAG_PID = "pid";
private static final String TAG_NAME = "name";
JSONArray products = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.all_products);
productsList = new ArrayList<HashMap<String, String>>();
new LoadAllProducts().execute();
ListView lv = getListView();
lv.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
String pid = ((TextView) view.findViewById(R.id.pid)).getText()
.toString();
Intent in = new Intent(getApplicationContext(),
EditProductActivity.class);
in.putExtra(TAG_PID, pid);
startActivityForResult(in, 100);
}
});
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
// if result code 100
if (resultCode == 100) {
Intent intent = getIntent();
finish();
startActivity(intent);
}
}
/**
* Background Async Task to Load all product by making HTTP Request
* */
class LoadAllProducts extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(AllProductsActivity.this);
pDialog.setMessage("Loading products. Please wait...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show();
}
/**
* getting All products from url
* */
protected String doInBackground(String... args) {
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
// getting JSON string from URL
JSONObject json = jParser.makeHttpRequest(url_all_products, "GET", params);
// Check your log cat for JSON reponse
Log.d("All Products: ", json.toString());
try {
// Checking for SUCCESS TAG
int success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// products found
// Getting Array of Products
products = json.getJSONArray(TAG_PRODUCTS);
// looping through All Products
for (int i = 0; i < products.length(); i++) {
JSONObject c = products.getJSONObject(i);
// Storing each json item in variable
String id = c.getString(TAG_PID);
String name = c.getString(TAG_NAME);
// creating new HashMap
HashMap<String, String> map = new HashMap<String, String>();
// adding each child node to HashMap key => value
map.put(TAG_PID, id);
map.put(TAG_NAME, name);
// adding HashList to ArrayList
productsList.add(map);
}
} else {
// no products found
// Launch Add New product Activity
Intent i = new Intent(getApplicationContext(),
NewProductActivity.class);
// Closing all previous activities
i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(i);
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
/**
* After completing background task Dismiss the progress dialog
* **/
protected void onPostExecute(String file_url) {
// dismiss the dialog after getting all products
pDialog.dismiss();
// updating UI from Background Thread
runOnUiThread(new Runnable() {
public void run() {
/**
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(
AllProductsActivity.this, productsList,
R.layout.list_item, new String[] { TAG_PID,
TAG_NAME},
new int[] { R.id.pid, R.id.name });
// updating listview
setListAdapter(adapter);
}
});
}
}
}
2.EditProductActivity:
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_detials = "http://10.0.2.2/android_connect/get_product_details.php";
// url to update product
private static final String url_update_product = "http://10.0.2.2/android_connect/update_product.php";
// url to delete product
private static final String url_delete_product = "http://10.0.2.2/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_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
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 Progress 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 the progress dialog
* **/
protected void onPostExecute(String file_url) {
// dismiss the dialog once product updated
pDialog.dismiss();
}
}
/*****************************************************************
* Background Async Task to Delete Product
* */
class DeleteProduct 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("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 the progress dialog
* **/
protected void onPostExecute(String file_url) {
// dismiss the dialog once product deleted
pDialog.dismiss();
}
}
}
3.JSONParser
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.List;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.utils.URLEncodedUtils;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONException;
import org.json.JSONObject;
import android.util.Log;
public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
// constructor
public JSONParser() {
}
// function get json from url
// by making HTTP POST or GET mehtod
public JSONObject makeHttpRequest(String url, String method,
List<NameValuePair> params) {
// Making HTTP request
try {
// check for request method
if(method == "POST"){
// request method is POST
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
httpPost.setEntity(new UrlEncodedFormEntity(params));
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
}else if(method == "GET"){
// request method is GET
DefaultHttpClient httpClient = new DefaultHttpClient();
String paramString = URLEncodedUtils.format(params, "utf-8");
url += "?" + paramString;
HttpGet httpGet = new HttpGet(url);
HttpResponse httpResponse = httpClient.execute(httpGet);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
}
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
json = sb.toString();
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
// try parse the string to a JSON object
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
}
4.MainScreenActivity;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class MainScreenActivity extends Activity{
Button btnViewProducts;
Button btnNewProduct;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_screen);
// Buttons
btnViewProducts = (Button) findViewById(R.id.btnViewProducts);
btnNewProduct = (Button) findViewById(R.id.btnCreateProduct);
// view products click event
btnViewProducts.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
// Launching All products Activity
Intent i = new Intent(getApplicationContext(), AllProductsActivity.class);
startActivity(i);
}
});
// view products click event
btnNewProduct.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
// Launching create new product activity
Intent i = new Intent(getApplicationContext(), NewProductActivity.class);
startActivity(i);
}
});
}
}
5.NewProductActivity:
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.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 NewProductActivity extends Activity {
// Progress Dialog
private ProgressDialog pDialog;
JSONParser jsonParser = new JSONParser();
EditText inputName;
EditText inputPrice;
EditText inputDesc;
// url to create new product
private static String url_create_product = "http://10.0.2.2/android_connect/create_product.php";
// JSON Node names
private static final String TAG_SUCCESS = "success";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.add_product);
// Edit Text
inputName = (EditText) findViewById(R.id.inputName);
inputPrice = (EditText) findViewById(R.id.inputPrice);
inputDesc = (EditText) findViewById(R.id.inputDesc);
// Create button
Button btnCreateProduct = (Button) findViewById(R.id.btnCreateProduct);
// button click event
btnCreateProduct.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
// creating new product in background thread
new CreateNewProduct().execute();
}
});
}
/**
* Background Async Task to Create new product
* */
class CreateNewProduct extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(NewProductActivity.this);
pDialog.setMessage("Creating Product..");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
/**
* Creating product
* */
protected String doInBackground(String... args) {
String name = inputName.getText().toString();
String price = inputPrice.getText().toString();
String description = inputDesc.getText().toString();
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("name", name));
params.add(new BasicNameValuePair("price", price));
params.add(new BasicNameValuePair("description", description));
JSONObject json = jsonParser.makeHttpRequest(url_create_product,
"POST", params);
Log.d("Create Response", json.toString());
try {
int success = json.getInt(TAG_SUCCESS);
if (success == 1) {
Intent i = new Intent(getApplicationContext(), AllProductsActivity.class);
startActivity(i);
finish();
} else {
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
protected void onPostExecute(String file_url) {
// dismiss the dialog once done
pDialog.dismiss();
}
}
}
这是LogCat错误：
12-10 15:37:48.934 338-568/com.example.androidhive E/AndroidRuntime? FATAL EXCEPTION: AsyncTask #1
java.lang.RuntimeException: An error occured while executing doInBackground()
at android.os.AsyncTask$3.done(AsyncTask.java:200)
at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:274)
at java.util.concurrent.FutureTask.setException(FutureTask.java:125)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:308)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1088)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:581)
at java.lang.Thread.run(Thread.java:1019)
Caused by: java.lang.IllegalArgumentException: Illegal character in authority at index 15: http://10.0.2.2 /android_connect/create_product.php
at java.net.URI.create(URI.java:776)
at org.apache.http.client.methods.HttpPost.<init>(HttpPost.java:79)
at com.example.androidhive.JSONParser.makeHttpRequest(JSONParser.java:48)
at com.example.androidhive.NewProductActivity$CreateNewProduct.doInBackground(NewProductActivity.java:95)
at com.example.androidhive.NewProductActivity$CreateNewProduct.doInBackground(NewProductActivity.java:64)
at android.os.AsyncTask$2.call(AsyncTask.java:185)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:306)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1088)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:581)
at java.lang.Thread.run(Thread.java:1019)
12-10 15:37:49.974 338-338/com.example.androidhive E/WindowManager? Activity com.example.androidhive.NewProductActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@405490f8 that was originally added here
android.view.WindowLeaked: Activity com.example.androidhive.NewProductActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@405490f8 that was originally added here
at android.view.ViewRoot.<init>(ViewRoot.java:258)
at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:148)
at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91)
at android.view.Window$LocalWindowManager.addView(Window.java:424)
at android.app.Dialog.show(Dialog.java:241)
at com.example.androidhive.NewProductActivity$CreateNewProduct.onPreExecute(NewProductActivity.java:76)
at android.os.AsyncTask.execute(AsyncTask.java:391)
at com.example.androidhive.NewProductActivity$1.onClick(NewProductActivity.java:56)
at android.view.View.performClick(View.java:2485)
at android.view.View$PerformClick.run(View.java:9080)
at android.os.Handler.handleCallback(Handler.java:587)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:123)
at android.app.ActivityThread.main(ActivityThread.java:3683)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:507)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
at dalvik.system.NativeStart
答案 0 :(得分：0)
此错误是由于http请求网址错误，因为您知道网址不允许任何空格或特殊字符，所以我们必须在发出请求之前对其进行编码，请打印您的网址，您将找到解决方案。