无法在我的 Android 应用程序中将数据从 mysql 数据库提取到 ListView
Unable to fetch data from mysql database to ListView in my Android Application
我的应用程序是这样工作的。首先，MainActivity.java 显示从 mysql 数据库中获取的电影列表。单击列表中的电影时，SongsActivity.java 打开并显示该特定电影中的歌曲列表。第一个 Activity 工作正常但是当我点击电影时，第二个 Activity 打开空白！没有提取正在完成！下面是我的代码，请帮助我。
MainActivity.java
package com.example.telugump3;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONArray;
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.Menu;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListView;
import android.widget.TextView;
public class MainActivity extends Activity{
Activity context;
HttpPost httppost;
StringBuffer buffer;
HttpResponse response;
HttpClient httpclient;
ProgressDialog pd;
CustomAdapter adapter;
ListView listProduct;
ArrayList<String> records;
protected void onCreate(Bundle savedInstanceState) {
//TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
context=this;
records=new ArrayList<String>();
listProduct=(ListView)findViewById(R.id.product_list);
adapter=new CustomAdapter(context, R.layout.list_item,R.id.pro_name, records);
listProduct.setAdapter(adapter);
listProduct.setOnItemClickListener(new OnItemClickListener(){
@Override
public void onItemClick(AdapterView<?> arg0, View v, int position, long id){
String sText = ((TextView) v.findViewById(R.id.pro_name)).getText().toString();
Intent songIntent = new Intent(getApplicationContext(), SongActivity.class);
songIntent.putExtra("movie_name", sText );
startActivity(songIntent);
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
//create a LayoutTransition object
return true;
}
public void onStart(){
super.onStart();
//execute background task
BackTask bt=new BackTask();
bt.execute();
}
//background process to make a request to server and list product information
private class BackTask extends AsyncTask<Void,Void,Void>{
protected void onPreExecute(){
super.onPreExecute();
pd = new ProgressDialog(context);
pd.setTitle("Retrieving data");
pd.setMessage("Please wait.");
pd.setCancelable(true);
pd.setIndeterminate(true);
pd.show();
}
protected Void doInBackground(Void...params){
InputStream is=null;
String result="";
try{
httpclient=new DefaultHttpClient();
httppost= new HttpPost("http://necrecords.16mb.com/getproducts.php");
response=httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
is = entity.getContent();
}catch(Exception e){
if(pd!=null)
pd.dismiss(); //close the dialog if error occurs
Log.e("ERROR",e.getMessage());
}
//convert response to string
try{
BufferedReader reader = new BufferedReader(new InputStreamReader(is,"utf-8"),8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
result=sb.toString();
}catch(Exception e){
Log.e("ERROR", "Error converting result "+e.toString());
}
//parse json data
try{
JSONArray jArray =new JSONArray(result);
for(int i=0;i<jArray.length();i++){
JSONObject json_data = jArray.getJSONObject(i);
String record = json_data.getString("pname")+"__"+json_data.getInt("uprice");
records.add(record);
}
}
catch(Exception e){
Log.e("ERROR", "Error pasting data "+e.toString());
}
return null;
}
protected void onPostExecute(Void result){
if(pd!=null) pd.dismiss(); //close dialog
adapter.notifyDataSetChanged(); //notify the ListView to get new records
}
}
}
SongsActivity.java
package com.example.telugump3;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONArray;
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.Menu;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListView;
import android.widget.TextView;
public class SongActivity extends Activity{
Activity context;
HttpPost httppost;
StringBuffer buffer;
HttpResponse response;
HttpClient httpclient;
ProgressDialog pd;
CustomAdapter adapter;
ListView listProduct;
ArrayList<String> records;
String mname;
protected void onCreate(Bundle savedInstanceState) {
//TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.song_activity);
context=this;
records=new ArrayList<String>();
listProduct=(ListView)findViewById(R.id.product_list);
adapter=new CustomAdapter(context, R.layout.newlist_item,R.id.pro_name, records);
listProduct.setAdapter(adapter);
Intent iin= getIntent();
Bundle b = iin.getExtras();
if(b!=null) {
mname =(String) b.getString("movie_name");
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
//create a LayoutTransition object
return true;
}
public void onStart(){
super.onStart();
//execute background task
BackTask bt=new BackTask();
bt.execute();
}
//background process to make a request to server and list product information
private class BackTask extends AsyncTask<Void,Void,Void>{
protected void onPreExecute(){
super.onPreExecute();
pd = new ProgressDialog(context);
pd.setTitle("Retrieving data");
pd.setMessage("Please wait.");
pd.setCancelable(true);
pd.setIndeterminate(true);
pd.show();
}
protected Void doInBackground(Void...params){
InputStream is=null;
String result="";
try{
httpclient=new DefaultHttpClient();
httppost= new HttpPost("http://necrecords.16mb.com/getsongslist.php?password="+mname);
response=httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
is = entity.getContent();
}catch(Exception e){
if(pd!=null)
pd.dismiss(); //close the dialog if error occurs
Log.e("ERROR",e.getMessage());
}
//convert response to string
try{
BufferedReader reader = new BufferedReader(new InputStreamReader(is,"utf-8"),8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
result=sb.toString();
}catch(Exception e){
Log.e("ERROR", "Error converting result "+e.toString());
}
//parse json data
try{
JSONArray jArray =new JSONArray(result);
for(int i=0;i<jArray.length();i++){
JSONObject json_data = jArray.getJSONObject(i);
String record = json_data.getString("allsongs")+"__"+json_data.getInt("test");
records.add(record);
}
}
catch(Exception e){
Log.e("ERROR", "Error pasting data "+e.toString());
}
return null;
}
protected void onPostExecute(Void result){
if(pd!=null) pd.dismiss(); //close dialog
adapter.notifyDataSetChanged(); //notify the ListView to get new records
}
}
}
CustomAdapter.java
package com.example.telugump3;
import java.util.ArrayList;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;
public class CustomAdapter extends ArrayAdapter<String> {
int groupid;
ArrayList<String> records;
Context context;
public CustomAdapter(Context context, int vg, int id, ArrayList<String> records){
super(context,vg, id, records);
this.context=context;
groupid=vg;
this.records=records;
}
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View itemView = inflater.inflate(groupid, parent, false);
String[] row_items=records.get(position).split("__");
TextView textName= (TextView) itemView.findViewById(R.id.pro_name);
textName.setText(row_items[0]);
TextView textPrice= (TextView) itemView.findViewById(R.id.pro_uprice);
textPrice.setText(row_items[1]+"$");
return itemView;
}
}
logcat
03-22 22:54:02.500: E/IMGSRV(7557): :0: PVRDRMOpen: TP3, ret = 37
03-22 22:54:02.500: E/IMGSRV(7557): :0: PVRDRMOpen: TP3, ret = 38
03-22 22:54:02.510: E/IMGSRV(7557): :0: PVRDRMOpen: TP3, ret = 38
03-22 22:54:02.510: E/IMGSRV(7557): :0: PVRDRMOpen: TP3, ret = 38
03-22 22:54:04.710: E/Launcher.Model(22911): Widget ComponentInfo{com.asus.calendar/com.android.calendar.widget2.CalendarAppWidgetPadProvider} has invalid dimensions (0, 0)
03-22 22:54:05.060: E/NetworkScheduler.SchedulerReceiver(16209): Invalid parameter app
03-22 22:54:05.060: E/NetworkScheduler.SchedulerReceiver(16209): Invalid package name : Perhaps you didn't include a PendingIntent in the extras?
03-22 22:54:05.600: E/IMGSRV(7586): :0: PVRDRMOpen: TP3, ret = 37
03-22 22:54:05.600: E/IMGSRV(7586): :0: PVRDRMOpen: TP3, ret = 38
03-22 22:54:05.600: E/IMGSRV(7586): :0: PVRDRMOpen: TP3, ret = 38
03-22 22:54:05.600: E/IMGSRV(7586): :0: PVRDRMOpen: TP3, ret = 38
03-22 22:54:05.790: E/IMGSRV(185): :0: PVRDRMOpen: TP3, ret = 62
03-22 22:54:05.840: E/Save(22911): com.android.launcher3.Workspace$$Icicle.
03-22 22:54:05.850: E/IMGSRV(185): :0: PVRDRMOpen: TP3, ret = 41
03-22 22:54:05.900: E/IMGSRV(185): :0: PVRDRMOpen: TP3, ret = 37
03-22 22:54:06.060: E/IMGSRV(7654): :0: PVRDRMOpen: TP3, ret = 46
03-22 22:54:06.070: E/IMGSRV(7654): :0: PVRDRMOpen: TP3, ret = 50
03-22 22:54:06.070: E/IMGSRV(7654): :0: PVRDRMOpen: TP3, ret = 51
03-22 22:54:06.070: E/IMGSRV(7654): :0: PVRDRMOpen: TP3, ret = 51
03-22 22:54:06.070: E/IMGSRV(7654): :0: PVRDRMOpen: TP3, ret = 51
03-22 22:54:06.090: E/IMGSRV(7654): :0: PVRDRMOpen: TP3, ret = 53
03-22 22:54:06.130: E/IMGSRV(185): :0: PVRDRMOpen: TP3, ret = 40
03-22 22:54:06.190: E/[ParseTask](2945): [doInBackground] fail to retrieve url: https://play.google.com/store/apps/details?id=com.example.telugump3&hl=en-US
03-22 22:54:06.210: E/IMGSRV(185): :0: PVRDRMOpen: TP3, ret = 50
03-22 22:54:06.300: E/IMGSRV(185): :0: PVRDRMOpen: TP3, ret = 55
03-22 22:54:06.320: E/IMGSRV(185): :0: PVRDRMOpen: TP3, ret = 62
03-22 22:54:06.330: E/IMGSRV(185): :0: PVRDRMOpen: TP3, ret = 36
03-22 22:54:06.340: E/IMGSRV(185): :0: PVRDRMOpen: TP3, ret = 66
03-22 22:54:06.680: E/NetworkScheduler.SchedulerReceiver(16209): Invalid parameter app
03-22 22:54:06.680: E/NetworkScheduler.SchedulerReceiver(16209): Invalid package name : Perhaps you didn't include a PendingIntent in the extras?
03-22 22:54:07.150: E/IMGSRV(185): :0: PVRDRMOpen: TP3, ret = 40
03-22 22:54:07.340: E/IMGSRV(185): :0: PVRDRMOpen: TP3, ret = 41
03-22 22:54:07.820: E/lights(560): [LED] open path fail.
03-22 22:54:08.000: E/ERROR(7654): Illegal character in query at index 54: http://necrecords.16mb.com/getsongslist.php?password=A AA E EEE
03-22 22:54:08.000: E/ERROR(7654): Error converting result java.lang.NullPointerException: lock == null
03-22 22:54:08.000: E/ERROR(7654): Error pasting data org.json.JSONException: End of input at character 0 of
03-22 22:54:08.040: E/IMGSRV(185): :0: PVRDRMOpen: TP3, ret = 37
03-22 22:54:08.060: E/IMGSRV(185): :0: PVRDRMOpen: TP3, ret = 55
03-22 22:54:08.110: E/IMGSRV(185): :0: PVRDRMOpen: TP3, ret = 53
03-22 22:54:08.450: E/IMGSRV(185): :0: PVRDRMOpen: TP3, ret = 40
03-22 22:54:10.810: E/IMGSRV(185): :0: PVRDRMOpen: TP3, ret = 34
03-22 22:54:10.830: E/lights(560): [LED] open path fail.
现在还有两个疑惑
1) 在 SongsActivity.java 中，我在 link 中使用了从第一个 Activity 获得的字符串来获取所需信息。这是在 url 中使用字符串的正确方法吗？
2) 当我按后退按钮到 return 到第一个 Activity 时，ListView 再次获取数据并且电影列表加倍。有解决办法吗？
这里发生了一些事情，我会尽力解决。
此日志条目可疑：
03-22 22:30:42.860: E/ERROR(6055): Illegal character in query at index 53: http://necrecords.16mb.com/getproducts.php?password=A AA E EEE
另外，从这个日志：
03-22 22:54:08.000: E/ERROR(7654): Error converting result java.lang.NullPointerException: lock == null
您可以看到您没有从该 PHP 页面获得有效响应。
此代码块抛出异常：
//convert response to string
try{
BufferedReader reader = new BufferedReader(new InputStreamReader(is,"utf-8"),8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
result=sb.toString();
}catch(Exception e){
Log.e("ERROR", "Error converting result "+e.toString());
我刚刚在浏览器中尝试了 URL，它成功了，因为浏览器会自动正确编码 url，如下所示：
http://necrecords.16mb.com/getproducts.php?password=A%20AA%20E%20EEE
我认为您只需要对 URL 进行正确编码，因为该字符串包含空格。
String query = URLEncoder.encode(mname, "utf-8");
httppost= new HttpPost("http://necrecords.16mb.com/getsongslist.php?password="+query);
response=httpclient.execute(httppost);
至于你的列表加倍的问题，你可以在每次 AsyncTask 执行时清除列表：
protected Void doInBackground(Void...params){
InputStream is=null;
String result="";
try{
records.clear(); //clear the list before re-populating
httpclient=new DefaultHttpClient();
httppost= new HttpPost("http://necrecords.16mb.com/getproducts.php");
response=httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
is = entity.getContent();
}catch(Exception e){
还有一件事要提，您可能希望为每个 Acitvity 创建一个单独的适配器。就像现在一样，您正在为两个活动使用相同的适配器。
在您的适配器 getView() 中，您引用了 R.id.pro_name 和 R.id.pro_uprice，但您在两个活动中都使用了此适配器。您的两个 Activity 的布局中是否都包含这些元素 xml？
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View itemView = inflater.inflate(groupid, parent, false);
String[] row_items=records.get(position).split("__");
TextView textName= (TextView) itemView.findViewById(R.id.pro_name);
textName.setText(row_items[0]);
TextView textPrice= (TextView) itemView.findViewById(R.id.pro_uprice);
textPrice.setText(row_items[1]+"$");
return itemView;
}
我的应用程序是这样工作的。首先，MainActivity.java 显示从 mysql 数据库中获取的电影列表。单击列表中的电影时，SongsActivity.java 打开并显示该特定电影中的歌曲列表。第一个 Activity 工作正常但是当我点击电影时，第二个 Activity 打开空白！没有提取正在完成！下面是我的代码，请帮助我。
MainActivity.java
package com.example.telugump3;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONArray;
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.Menu;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListView;
import android.widget.TextView;
public class MainActivity extends Activity{
Activity context;
HttpPost httppost;
StringBuffer buffer;
HttpResponse response;
HttpClient httpclient;
ProgressDialog pd;
CustomAdapter adapter;
ListView listProduct;
ArrayList<String> records;
protected void onCreate(Bundle savedInstanceState) {
//TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
context=this;
records=new ArrayList<String>();
listProduct=(ListView)findViewById(R.id.product_list);
adapter=new CustomAdapter(context, R.layout.list_item,R.id.pro_name, records);
listProduct.setAdapter(adapter);
listProduct.setOnItemClickListener(new OnItemClickListener(){
@Override
public void onItemClick(AdapterView<?> arg0, View v, int position, long id){
String sText = ((TextView) v.findViewById(R.id.pro_name)).getText().toString();
Intent songIntent = new Intent(getApplicationContext(), SongActivity.class);
songIntent.putExtra("movie_name", sText );
startActivity(songIntent);
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
//create a LayoutTransition object
return true;
}
public void onStart(){
super.onStart();
//execute background task
BackTask bt=new BackTask();
bt.execute();
}
//background process to make a request to server and list product information
private class BackTask extends AsyncTask<Void,Void,Void>{
protected void onPreExecute(){
super.onPreExecute();
pd = new ProgressDialog(context);
pd.setTitle("Retrieving data");
pd.setMessage("Please wait.");
pd.setCancelable(true);
pd.setIndeterminate(true);
pd.show();
}
protected Void doInBackground(Void...params){
InputStream is=null;
String result="";
try{
httpclient=new DefaultHttpClient();
httppost= new HttpPost("http://necrecords.16mb.com/getproducts.php");
response=httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
is = entity.getContent();
}catch(Exception e){
if(pd!=null)
pd.dismiss(); //close the dialog if error occurs
Log.e("ERROR",e.getMessage());
}
//convert response to string
try{
BufferedReader reader = new BufferedReader(new InputStreamReader(is,"utf-8"),8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
result=sb.toString();
}catch(Exception e){
Log.e("ERROR", "Error converting result "+e.toString());
}
//parse json data
try{
JSONArray jArray =new JSONArray(result);
for(int i=0;i<jArray.length();i++){
JSONObject json_data = jArray.getJSONObject(i);
String record = json_data.getString("pname")+"__"+json_data.getInt("uprice");
records.add(record);
}
}
catch(Exception e){
Log.e("ERROR", "Error pasting data "+e.toString());
}
return null;
}
protected void onPostExecute(Void result){
if(pd!=null) pd.dismiss(); //close dialog
adapter.notifyDataSetChanged(); //notify the ListView to get new records
}
}
}
SongsActivity.java
package com.example.telugump3;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONArray;
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.Menu;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListView;
import android.widget.TextView;
public class SongActivity extends Activity{
Activity context;
HttpPost httppost;
StringBuffer buffer;
HttpResponse response;
HttpClient httpclient;
ProgressDialog pd;
CustomAdapter adapter;
ListView listProduct;
ArrayList<String> records;
String mname;
protected void onCreate(Bundle savedInstanceState) {
//TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.song_activity);
context=this;
records=new ArrayList<String>();
listProduct=(ListView)findViewById(R.id.product_list);
adapter=new CustomAdapter(context, R.layout.newlist_item,R.id.pro_name, records);
listProduct.setAdapter(adapter);
Intent iin= getIntent();
Bundle b = iin.getExtras();
if(b!=null) {
mname =(String) b.getString("movie_name");
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
//create a LayoutTransition object
return true;
}
public void onStart(){
super.onStart();
//execute background task
BackTask bt=new BackTask();
bt.execute();
}
//background process to make a request to server and list product information
private class BackTask extends AsyncTask<Void,Void,Void>{
protected void onPreExecute(){
super.onPreExecute();
pd = new ProgressDialog(context);
pd.setTitle("Retrieving data");
pd.setMessage("Please wait.");
pd.setCancelable(true);
pd.setIndeterminate(true);
pd.show();
}
protected Void doInBackground(Void...params){
InputStream is=null;
String result="";
try{
httpclient=new DefaultHttpClient();
httppost= new HttpPost("http://necrecords.16mb.com/getsongslist.php?password="+mname);
response=httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
is = entity.getContent();
}catch(Exception e){
if(pd!=null)
pd.dismiss(); //close the dialog if error occurs
Log.e("ERROR",e.getMessage());
}
//convert response to string
try{
BufferedReader reader = new BufferedReader(new InputStreamReader(is,"utf-8"),8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
result=sb.toString();
}catch(Exception e){
Log.e("ERROR", "Error converting result "+e.toString());
}
//parse json data
try{
JSONArray jArray =new JSONArray(result);
for(int i=0;i<jArray.length();i++){
JSONObject json_data = jArray.getJSONObject(i);
String record = json_data.getString("allsongs")+"__"+json_data.getInt("test");
records.add(record);
}
}
catch(Exception e){
Log.e("ERROR", "Error pasting data "+e.toString());
}
return null;
}
protected void onPostExecute(Void result){
if(pd!=null) pd.dismiss(); //close dialog
adapter.notifyDataSetChanged(); //notify the ListView to get new records
}
}
}
CustomAdapter.java
package com.example.telugump3;
import java.util.ArrayList;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;
public class CustomAdapter extends ArrayAdapter<String> {
int groupid;
ArrayList<String> records;
Context context;
public CustomAdapter(Context context, int vg, int id, ArrayList<String> records){
super(context,vg, id, records);
this.context=context;
groupid=vg;
this.records=records;
}
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View itemView = inflater.inflate(groupid, parent, false);
String[] row_items=records.get(position).split("__");
TextView textName= (TextView) itemView.findViewById(R.id.pro_name);
textName.setText(row_items[0]);
TextView textPrice= (TextView) itemView.findViewById(R.id.pro_uprice);
textPrice.setText(row_items[1]+"$");
return itemView;
}
}
logcat
03-22 22:54:02.500: E/IMGSRV(7557): :0: PVRDRMOpen: TP3, ret = 37
03-22 22:54:02.500: E/IMGSRV(7557): :0: PVRDRMOpen: TP3, ret = 38
03-22 22:54:02.510: E/IMGSRV(7557): :0: PVRDRMOpen: TP3, ret = 38
03-22 22:54:02.510: E/IMGSRV(7557): :0: PVRDRMOpen: TP3, ret = 38
03-22 22:54:04.710: E/Launcher.Model(22911): Widget ComponentInfo{com.asus.calendar/com.android.calendar.widget2.CalendarAppWidgetPadProvider} has invalid dimensions (0, 0)
03-22 22:54:05.060: E/NetworkScheduler.SchedulerReceiver(16209): Invalid parameter app
03-22 22:54:05.060: E/NetworkScheduler.SchedulerReceiver(16209): Invalid package name : Perhaps you didn't include a PendingIntent in the extras?
03-22 22:54:05.600: E/IMGSRV(7586): :0: PVRDRMOpen: TP3, ret = 37
03-22 22:54:05.600: E/IMGSRV(7586): :0: PVRDRMOpen: TP3, ret = 38
03-22 22:54:05.600: E/IMGSRV(7586): :0: PVRDRMOpen: TP3, ret = 38
03-22 22:54:05.600: E/IMGSRV(7586): :0: PVRDRMOpen: TP3, ret = 38
03-22 22:54:05.790: E/IMGSRV(185): :0: PVRDRMOpen: TP3, ret = 62
03-22 22:54:05.840: E/Save(22911): com.android.launcher3.Workspace$$Icicle.
03-22 22:54:05.850: E/IMGSRV(185): :0: PVRDRMOpen: TP3, ret = 41
03-22 22:54:05.900: E/IMGSRV(185): :0: PVRDRMOpen: TP3, ret = 37
03-22 22:54:06.060: E/IMGSRV(7654): :0: PVRDRMOpen: TP3, ret = 46
03-22 22:54:06.070: E/IMGSRV(7654): :0: PVRDRMOpen: TP3, ret = 50
03-22 22:54:06.070: E/IMGSRV(7654): :0: PVRDRMOpen: TP3, ret = 51
03-22 22:54:06.070: E/IMGSRV(7654): :0: PVRDRMOpen: TP3, ret = 51
03-22 22:54:06.070: E/IMGSRV(7654): :0: PVRDRMOpen: TP3, ret = 51
03-22 22:54:06.090: E/IMGSRV(7654): :0: PVRDRMOpen: TP3, ret = 53
03-22 22:54:06.130: E/IMGSRV(185): :0: PVRDRMOpen: TP3, ret = 40
03-22 22:54:06.190: E/[ParseTask](2945): [doInBackground] fail to retrieve url: https://play.google.com/store/apps/details?id=com.example.telugump3&hl=en-US
03-22 22:54:06.210: E/IMGSRV(185): :0: PVRDRMOpen: TP3, ret = 50
03-22 22:54:06.300: E/IMGSRV(185): :0: PVRDRMOpen: TP3, ret = 55
03-22 22:54:06.320: E/IMGSRV(185): :0: PVRDRMOpen: TP3, ret = 62
03-22 22:54:06.330: E/IMGSRV(185): :0: PVRDRMOpen: TP3, ret = 36
03-22 22:54:06.340: E/IMGSRV(185): :0: PVRDRMOpen: TP3, ret = 66
03-22 22:54:06.680: E/NetworkScheduler.SchedulerReceiver(16209): Invalid parameter app
03-22 22:54:06.680: E/NetworkScheduler.SchedulerReceiver(16209): Invalid package name : Perhaps you didn't include a PendingIntent in the extras?
03-22 22:54:07.150: E/IMGSRV(185): :0: PVRDRMOpen: TP3, ret = 40
03-22 22:54:07.340: E/IMGSRV(185): :0: PVRDRMOpen: TP3, ret = 41
03-22 22:54:07.820: E/lights(560): [LED] open path fail.
03-22 22:54:08.000: E/ERROR(7654): Illegal character in query at index 54: http://necrecords.16mb.com/getsongslist.php?password=A AA E EEE
03-22 22:54:08.000: E/ERROR(7654): Error converting result java.lang.NullPointerException: lock == null
03-22 22:54:08.000: E/ERROR(7654): Error pasting data org.json.JSONException: End of input at character 0 of
03-22 22:54:08.040: E/IMGSRV(185): :0: PVRDRMOpen: TP3, ret = 37
03-22 22:54:08.060: E/IMGSRV(185): :0: PVRDRMOpen: TP3, ret = 55
03-22 22:54:08.110: E/IMGSRV(185): :0: PVRDRMOpen: TP3, ret = 53
03-22 22:54:08.450: E/IMGSRV(185): :0: PVRDRMOpen: TP3, ret = 40
03-22 22:54:10.810: E/IMGSRV(185): :0: PVRDRMOpen: TP3, ret = 34
03-22 22:54:10.830: E/lights(560): [LED] open path fail.
现在还有两个疑惑
1) 在 SongsActivity.java 中，我在 link 中使用了从第一个 Activity 获得的字符串来获取所需信息。这是在 url 中使用字符串的正确方法吗？
2) 当我按后退按钮到 return 到第一个 Activity 时，ListView 再次获取数据并且电影列表加倍。有解决办法吗？
这里发生了一些事情，我会尽力解决。
此日志条目可疑：
03-22 22:30:42.860: E/ERROR(6055): Illegal character in query at index 53: http://necrecords.16mb.com/getproducts.php?password=A AA E EEE
另外，从这个日志：
03-22 22:54:08.000: E/ERROR(7654): Error converting result java.lang.NullPointerException: lock == null
您可以看到您没有从该 PHP 页面获得有效响应。
此代码块抛出异常：
//convert response to string
try{
BufferedReader reader = new BufferedReader(new InputStreamReader(is,"utf-8"),8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
result=sb.toString();
}catch(Exception e){
Log.e("ERROR", "Error converting result "+e.toString());
我刚刚在浏览器中尝试了 URL，它成功了，因为浏览器会自动正确编码 url，如下所示：
http://necrecords.16mb.com/getproducts.php?password=A%20AA%20E%20EEE
我认为您只需要对 URL 进行正确编码，因为该字符串包含空格。
String query = URLEncoder.encode(mname, "utf-8");
httppost= new HttpPost("http://necrecords.16mb.com/getsongslist.php?password="+query);
response=httpclient.execute(httppost);
至于你的列表加倍的问题，你可以在每次 AsyncTask 执行时清除列表：
protected Void doInBackground(Void...params){
InputStream is=null;
String result="";
try{
records.clear(); //clear the list before re-populating
httpclient=new DefaultHttpClient();
httppost= new HttpPost("http://necrecords.16mb.com/getproducts.php");
response=httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
is = entity.getContent();
}catch(Exception e){
还有一件事要提，您可能希望为每个 Acitvity 创建一个单独的适配器。就像现在一样，您正在为两个活动使用相同的适配器。
在您的适配器 getView() 中，您引用了 R.id.pro_name 和 R.id.pro_uprice，但您在两个活动中都使用了此适配器。您的两个 Activity 的布局中是否都包含这些元素 xml？
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View itemView = inflater.inflate(groupid, parent, false);
String[] row_items=records.get(position).split("__");
TextView textName= (TextView) itemView.findViewById(R.id.pro_name);
textName.setText(row_items[0]);
TextView textPrice= (TextView) itemView.findViewById(R.id.pro_uprice);
textPrice.setText(row_items[1]+"$");
return itemView;
}