我有一个列表视图，其中显示了50个元素。我决定对视图进行分页处理，每个部分显示10个元素，然后点击下一页按钮以获取下一个10个元素。如何设置10个数据？我遵循了这篇文章
http://rakhi577.wordpress.com/2013/05/20/listview-pagination-ex-2/
以下是我的代码。你能帮我检查一下代码或者提供一个正确实现的指南吗？
public class MainActivity extends ListActivity {
Context context;
Button btnSearch ;
EditText txtSearch;
private ProgressDialog pDialog;
// URL to get contacts JSON
public int TOTAL_LIST_ITEMS = 50;
public int NUM_ITEMS_PAGE = 10;
private int noOfBtns;
private Button[] btns;
// JSON Node names
private static final String TAG_CONTACTS = "contacts";
private static final String TAG_ID = "id";
private static final String TAG_NAME = "name";
private static final String TAG_EMAIL = "email";
private static final String TAG_ADDRESS = "address";
private static final String TAG_GENDER = "gender";
private static final String TAG_PHONE = "phone";
private static final String TAG_PHONE_MOBILE = "mobile";
private static final String TAG_PHONE_HOME = "home";
private static final String TAG_PHONE_OFFICE = "office";
// contacts JSONArray
JSONArray contacts = null;
// Hashmap for ListView
ArrayList<HashMap<String, String>> contactList;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btnSearch=(Button)findViewById(R.id.buttonSearch);
txtSearch=(EditText)findViewById(R.id.Searchtext);
}
public String gotourl()
{
final EditText txtSearch=(EditText)findViewById(R.id.Searchtext);
String ts=txtSearch.getText().toString();
String url = "http://latest.bloomapi.com/api/search?limit=50&offset=0&key1=last_name&op1=eq&value1="+ts;
return url ;
}
public void Searchfunction(View v)
{
Btnfooter();
//loadList(0);
CheckBtnBackGroud(0);
contactList = new ArrayList<HashMap<String, String>>();
ListView lv = getListView();
// Listview on item click listener
lv.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// getting values from selected ListItem
String name = ((TextView) view.findViewById(R.id.name))
.getText().toString();
String cost = ((TextView) view.findViewById(R.id.email))
.getText().toString();
String description = ((TextView) view.findViewById(R.id.mobile))
.getText().toString();
// Starting single contact activity
Intent in = new Intent(getApplicationContext(),
SingleContactActivity.class);
in.putExtra(TAG_NAME, name);
in.putExtra(TAG_EMAIL, cost);
in.putExtra(TAG_PHONE_MOBILE, description);
startActivity(in);
}
});
// Calling async task to get json
new GetContacts().execute();
}
private void Btnfooter()
{
int val = TOTAL_LIST_ITEMS%NUM_ITEMS_PAGE;
val = val==0?0:1;
noOfBtns=TOTAL_LIST_ITEMS/NUM_ITEMS_PAGE+val;
LinearLayout ll = (LinearLayout)findViewById(R.id.btnLay);
btns =new Button[noOfBtns];
for(int i=0;i<noOfBtns;i++)
{
btns[i] = new Button(this);
btns[i].setBackgroundColor(getResources().getColor(android.R.color.transparent));
btns[i].setText(""+(i+1));
LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
ll.addView(btns[i], lp);
final int j = i;
btns[j].setOnClickListener(new OnClickListener() {
public void onClick(View v)
{
//loadList(j);
CheckBtnBackGroud(j);
}
});
}
}
private void CheckBtnBackGroud(int index)
{
for(int i=0;i<noOfBtns;i++)
{
if(i==index)
{
btns[index].setBackgroundDrawable(getResources().getDrawable(R.drawable.box_green));
btns[i].setTextColor(getResources().getColor(android.R.color.white));
}
else
{
btns[i].setBackgroundColor(getResources().getColor(android.R.color.transparent));
btns[i].setTextColor(getResources().getColor(android.R.color.black));
}
}
}
private class GetContacts extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
pDialog = new ProgressDialog(MainActivity.this);
pDialog.setMessage("Please wait...");
pDialog.setCancelable(false);
pDialog.show();
}
@Override
protected Void doInBackground(Void... arg0) {
// Creating service handler class instance
ServiceHandler sh = new ServiceHandler();
// Making a request to url and getting response
String jsonStr = sh.makeServiceCall(gotourl(), ServiceHandler.GET);
Log.d("Response: ", "> " + jsonStr);
if (jsonStr != null) {
try {
JSONObject jsonObj = new JSONObject(jsonStr);
// Getting JSON Array node
contacts = jsonObj.getJSONArray("result");
// looping through All Contacts
for (int i = 0; i < contacts.length(); i++) {
Integer a = contacts.length();
Log.d("loop", a.toString());
JSONObject c = contacts.getJSONObject(i);
String id = c.getString("npi");
String name = c.getString("first_name");
String email = c.getString("last_name");
//String address = c.getString(TAG_ADDRESS);
String gender = c.getString("type");
// tmp hashmap for single contact
HashMap<String, String> contact = new HashMap<String, String>();
// adding each child node to HashMap key => value
contact.put("npi", id);
contact.put("first_name", name);
contact.put("last_name", email);
//contact.put(TAG_PHONE_MOBILE, mobile);
contact.put("type", gender);
// adding contact to contact list
contactList.add(contact);
}
} catch (JSONException e) {
e.printStackTrace();
}
} else {
Log.d("ServiceHandler", "Couldn't get any data from the url");
}
return null;
}
@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
// Dismiss the progress dialog
if (pDialog.isShowing())
pDialog.dismiss();
/**
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(
MainActivity.this, contactList,
R.layout.list_item, new String[] { "first_name", "last_name",
"type" }, new int[] { R.id.name,
R.id.email, R.id.mobile });
setListAdapter(adapter);
}
}}
我修改了代码。当我点击下一页按钮（如2、3、4、5），却显示第一页的数据。以下是我的修改后的代码，请大家帮忙看一下：
public class MainActivity extends ListActivity {
private TextView title;
Context context;
Button btnSearch ;
EditText txtSearch;
private ListView listview;
private ProgressDialog pDialog;
// URL to get contacts JSON
public int TOTAL_LIST_ITEMS = 50;
public int NUM_ITEMS_PAGE = 10;
private int noOfBtns;
private Button[] btns;
// JSON Node names
private static final String TAG_CONTACTS = "contacts";
private static final String TAG_ID = "id";
private static final String TAG_NAME = "name";
private static final String TAG_EMAIL = "email";
private static final String TAG_ADDRESS = "address";
private static final String TAG_GENDER = "gender";
private static final String TAG_PHONE = "phone";
private static final String TAG_PHONE_MOBILE = "mobile";
private static final String TAG_PHONE_HOME = "home";
private static final String TAG_PHONE_OFFICE = "office";
// contacts JSONArray
JSONArray contacts = null;
// Hashmap for ListView
ArrayList<HashMap<String, String>> contactList;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btnSearch=(Button)findViewById(R.id.buttonSearch);
txtSearch=(EditText)findViewById(R.id.Searchtext);
title = (TextView)findViewById(R.id.title);
}
public String gotourl()
{
final EditText txtSearch=(EditText)findViewById(R.id.Searchtext);
String ts=txtSearch.getText().toString();
String url = "http://latest.bloomapi.com/api/search?limit=50&offset=0&key1=last_name&op1=eq&value1="+ts;
return url ;
}
public void Searchfunction(View v)
{
Btnfooter();
CheckBtnBackGroud(0);
contactList = new ArrayList<HashMap<String, String>>();
ListView lv = getListView();
// Listview on item click listener
lv.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
if(position%2==0)
{
view.setBackgroundColor(Color.parseColor("#F4FA58"));
}else
{
view.setBackgroundColor(Color.parseColor("#DA81F5"));
}
// getting values from selected ListItem
String name = ((TextView) view.findViewById(R.id.name))
.getText().toString();
String cost = ((TextView) view.findViewById(R.id.email))
.getText().toString();
String description = ((TextView) view.findViewById(R.id.mobile))
.getText().toString();
// Starting single contact activity
Intent in = new Intent(getApplicationContext(),
SingleContactActivity.class);
in.putExtra(TAG_NAME, name);
in.putExtra(TAG_EMAIL, cost);
in.putExtra(TAG_PHONE_MOBILE, description);
startActivity(in);
}
});
// Calling async task to get json
new GetContacts().execute();
}
private void Btnfooter()
{
int val = TOTAL_LIST_ITEMS%NUM_ITEMS_PAGE;
val = val==0?0:1;
noOfBtns=TOTAL_LIST_ITEMS/NUM_ITEMS_PAGE+val;
LinearLayout ll = (LinearLayout)findViewById(R.id.btnLay);
btns =new Button[noOfBtns];
for(int i=0;i<noOfBtns;i++)
{
btns[i] = new Button(this);
btns[i].setBackgroundColor(getResources().getColor(android.R.color.transparent));
btns[i].setText(""+(i+1));
LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
ll.addView(btns[i], lp);
final int j = i;
btns[j].setOnClickListener(new OnClickListener() {
public void onClick(View v)
{
new GetContacts().execute();
CheckBtnBackGroud(j);
}
});
}
}
private void CheckBtnBackGroud(int index)
{
title.setText("Page "+(index+1)+" of "+noOfBtns);
for(int i=0;i<noOfBtns;i++)
{
if(i==index)
{
btns[index].setBackgroundDrawable(getResources().getDrawable(R.drawable.box_green));
btns[i].setTextColor(getResources().getColor(android.R.color.white));
}
else
{
btns[i].setBackgroundColor(getResources().getColor(android.R.color.transparent));
btns[i].setTextColor(getResources().getColor(android.R.color.black));
}
}
}
private class GetContacts extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
pDialog = new ProgressDialog(MainActivity.this);
pDialog.setMessage("Please wait...");
pDialog.setCancelable(false);
pDialog.show();
}
@Override
protected Void doInBackground(Void... arg0) {
// Creating service handler class instance
ServiceHandler sh = new ServiceHandler();
// Making a request to url and getting response
String jsonStr = sh.makeServiceCall(gotourl(), ServiceHandler.GET);
Log.d("Response: ", "> " + jsonStr);
if (jsonStr != null) {
try {
JSONObject jsonObj = new JSONObject(jsonStr);
int number = 0;
int start = number * NUM_ITEMS_PAGE;
// looping through All Contacts
// Getting JSON Array node
contacts = jsonObj.getJSONArray("result");
// looping through All Contacts
//for (int i = 0; i < contacts.length(); i++) {
for(int i=start;i<(start)+NUM_ITEMS_PAGE;i++) {
Integer a = contacts.length();
Log.d("loop", a.toString());
JSONObject c = contacts.getJSONObject(i);
String id = c.getString("npi");
String name = c.getString("first_name");
String email = c.getString("last_name");
String gender = c.getString("type");
// tmp hashmap for single contact
HashMap<String, String> contact = new HashMap<String, String>();
// adding each child node to HashMap key => value
contact.put("npi", id);
contact.put("first_name", name);
contact.put("last_name", email);
//contact.put(TAG_PHONE_MOBILE, mobile);
contact.put("type", gender);
// adding contact to contact list
contactList.add(contact);
}
} catch (JSONException e) {
e.printStackTrace();
}
} else {
Log.d("ServiceHandler", "Couldn't get any data from the url");
}
return null;
}
@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
// Dismiss the progress dialog
if (pDialog.isShowing())
pDialog.dismiss();
/**
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(
MainActivity.this, contactList,
R.layout.list_item, new String[] { "first_name", "last_name",
"type" }, new int[] { R.id.name,
R.id.email, R.id.mobile });
setListAdapter(adapter);
}
}}