我使用以下代码创建了listview
public class homeScreen extends Activity{
ArrayList<SingleRow> list;
boolean flag = false;
String space = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
final Context c = this;
super.onCreate(savedInstanceState);
setContentView(R.layout.homescreen);
//putting actual values in array
list = new ArrayList<SingleRow>();
Resources res = c.getResources();
String[] titles = res.getStringArray(R.array.titles);
int[] images = {R.drawable.error,R.drawable.ic_launcher,R.drawable.ic_launcher};
//putting single row in arraylist
for(int i = 0;i<3;i++){
list.add(new SingleRow(titles[i], images[i]));
}
final ListView list1 = (ListView)findViewById(R.id.spacelist);
final MySimpleAdapter adapter = new MySimpleAdapter(this,list);
list1.setAdapter(adapter);
space = getIntent().getStringExtra("spaceName");
if(null! = space){
adapter.addView(space);
}
list1.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> arg0, View v, int position, long id) {
Resources res = c.getResources();
String[] titles = res.getStringArray(R.array.titles);
if((titles[position]).equalsIgnoreCase("My Ideas")){
Intent i = new Intent(homeScreen.this, privateSpaceList.class);
startActivity(i);
} else if((titles[position]).equalsIgnoreCase("Create New Space")){
Intent i = new Intent(homeScreen.this, createNewSpace.class);
startActivity(i);
}
}
});
}
}
行类：
class SingleRow{
String title;
int image;
public SingleRow(String title,int image) {
this.title = title;
this.image = image;
}
}
适配器：
class MySimpleAdapter extends BaseAdapter{
ArrayList<SingleRow> list;
private Context context;
public MySimpleAdapter(Context c,ArrayList<SingleRow> list) {
this.context = c;
this.list = list;
}
@Override
public int getCount() {
return list.size();
}
@Override
public Object getItem(int i) {
return list.get(i);
}
@Override
public long getItemId(int i) {
return i;
}
public void addView(String space) {
int rows = this.getCount();
list.add(rows, new SingleRow(space,R.drawable.ic_launcher));
notifyDataSetChanged();
}
@Override
public View getView(int i, View view, ViewGroup viewgroup) {
LayoutInflater inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View row = inflater.inflate(R.layout.single_row,viewgroup,false);
TextView title = (TextView)row.findViewById(R.id.label);
ImageView image = (ImageView)row.findViewById(R.id.imageView);
SingleRow temp = list.get(i);
title.setText(temp.title);
image.setImageResource(temp.image);
return row;
}
}
创建新空间的代码
public class createNewSpace extends Activity{
Button add;
TextView sname,pname;
ListView plist;
int success;
Jparser jsonParser = new Jparser();
JSONObject json;
private ProgressDialog pDialog;
ArrayList<String> usersList;
ArrayList<String> spaceUsers;
private static String url_users = "http://10.0.2.2/phpdata/getting_allusers.php";
private static String url_create_space = "http://10.0.2.2/phpdata/create_space.php";
private static final String TAG_SUCCESS = "success";
private static final String TAG_USERS = "users";
private static final String TAG_UNAME = "firstName";
// products JSONArray
JSONArray users = null;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.createnewspace);
sname=(TextView)findViewById(R.id.spaceName);
pname=(TextView)findViewById(R.id.participents);
plist=(ListView)findViewById(R.id.participantlist);
add=(Button)findViewById(R.id.button1);
// Hashmap for ListView
usersList= new ArrayList<String>();
spaceUsers=new ArrayList<String>();
add.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
new getAllUsers().execute();
}
});
plist.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
long arg3) {
// TODO Auto-generated method stub
String users[]=usersList.toArray(new String[usersList.size()]);
Toast.makeText(getApplicationContext(), "User "+users[arg2]+ " added to space "+sname.getText(), Toast.LENGTH_SHORT).show();
spaceUsers.add(users[arg2]);
}
});
// Loading users in Background Thread
}
public boolean onCreateOptionsMenu(Menu menu) {
// TODO Auto-generated method stub
super.onCreateOptionsMenu(menu);
getMenuInflater().inflate(R.menu.menuspace, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// TODO Auto-generated method stub
return MenuChoice(item);
}
private boolean MenuChoice(MenuItem item)
{
switch(item.getItemId())
{
case R.id.create:
new createSpace().execute();
return true;
}
return false;
}
class createSpace extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
}
@Override
protected String doInBackground(String... arg0) {
// TODO Auto-generated method stub
for(int i=0;i<spaceUsers.size();i++)
{
String sname1 = sname.getText().toString();
String uname = spaceUsers.get(i);
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("sname", sname1));
params.add(new BasicNameValuePair("uname", uname));
// getting JSON Object
JSONObject json = jsonParser.makeHttpRequest(url_create_space,
"POST", params);
Log.d("Create Response", json.toString());
// check for success tag
try {
int success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// successfully inserted user details
Intent is = new Intent(getApplicationContext(), homeScreen.class);
is.putExtra("spaceName", sname1);
startActivity(is);
// closing this screen
finish();
} else {
}
} catch (JSONException e) {
e.printStackTrace();
}
}
return null;
}
protected void onPostExecute(String file_url) {
// dismiss the dialog once done
}
}
class getAllUsers extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
}
@Override
protected String doInBackground(String... arg0) {
// TODO Auto-generated method stub
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
// getting JSON Object
json = jsonParser.makeHttpRequest(url_users,"GET", params);
// check log cat from response
Log.d("Create Response", json.toString());
// getting value of success tag
try {
success = json.getInt(TAG_SUCCESS);
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
protected void onPostExecute(String file_url) {
if (success == 1) {
// Getting Array of users
try{
JSONArray users=json.getJSONArray(TAG_USERS);
// looping through All Products
for (int i = 0; i < users.length(); i++) {
Log.d("check", "success");
JSONObject c = users.getJSONObject(i);
// Storing each json item in variable
String name = c.getString(TAG_UNAME);
Log.d("name....",name);
// adding HashList to ArrayList
usersList.add(name);
}
} catch(JSONException e)
{
e.printStackTrace();
}
}
runOnUiThread(new Runnable() {
public void run() {
/**
* Updating parsed JSON data into ListView
* */
plist.setAdapter(new ArrayAdapter<String>(createNewSpace.this,android.R.layout.simple_list_item_1,usersList));
}
});
}
}
}
现在我想将Item添加到此现有列表中。 我正在使用意图从另一个活动中获取数据。 现在有一个项目被添加。但下次被替换。 请帮忙。 提前谢谢。
答案 0 :(得分：1)
您应该在适配器之外移动数据的创建：
list=new ArrayList<SingleRow>();
//putting actual values in array
Resources res=c.getResources();
String[] titles=res.getStringArray(R.array.titles);
int[] images={R.drawable.error,R.drawable.ic_launcher,R.drawable.ic_launcher};
//putting single row in arraylist
for(int i=0;i<3;i++){
list.add(new SingleRow(titles[i], images[i]));
}
将list变量传递给适配器并在那里存储对它的引用。然后，您只需更新列表变量中的数据，然后在适配器上调用notifyDataSetChanged()。
修改：您似乎希望存储space值，然后在HomeScreen活动中检索它们。如果我正确了解您的应用流程，那么createNewSpace类应该将空间存储在SharedPreferences中。然后在HomeScreen活动中，您应该从SharedPreferences中检索它们并显示它们。
答案 1 :(得分：0)
您可以向适配器添加数据并调用notifyDataSetChanged()。或者，您可以创建新的适配器和listView.setAdapter(adapter)该适配器。