我是android的新人。我正在尝试开发一个客户端app.Anyway，我有用户个人资料活动，其中有朋友和关注者，并且正在使用textview显示计数。当用户点击关注者计数时，textview会在对话框中看到朋友列表作为列表视图。它创建了一个apiclient对象，用于从服务器检索数据为json格式。
friendsCountTxtView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
MyTApiClients apiclients = new MyApiClients(session);
apiclients.getFriendsListService().show(userID, userName, -1, countForList, new Callback<Response>() {
@Override
public void success(Result<Response> result) {
BufferedReader reader;
StringBuilder sb = new StringBuilder();
try {
reader = new BufferedReader(new InputStreamReader(result.response.getBody().in()));
String line;
while ((line = reader.readLine()) != null) {
sb.append(line);
}
} catch (IOException e) {
e.printStackTrace();
}
String jsonResult = sb.toString();
try {
JSONObject objResult = new JSONObject(jsonResult);
nextCursor = Long.parseLong(objResult.getString("next_cursor"));
ListViewLoaderTask listViewLoaderTask = new ListViewLoaderTask();
listViewLoaderTask.execute(jsonResult);
} catch (JSONException e) {
e.printStackTrace();
}
}
@Override
public void failure(Exception e) {
}
});
}
});
我使用asyncTask解析jsonobject并将其绑定到listview。
private class ListViewLoaderTask extends AsyncTask<String, Void, SimpleAdapter> {
JSONObject jObject;
/** Returning an Adapter For Using Post Execute*/
@Override
protected SimpleAdapter doInBackground(String... strJson) {
try{
jObject = new JSONObject(strJson[0]);
UserProfileJsonParser userProfileJsonParser = new UserProfileJsonParser();
userProfileJsonParser.parse(jObject);
}catch(Exception e){
Log.d("JSON Exception1", e.toString());
}
UserProfileJsonParser userProfileJsonParser = new UserProfileJsonParser();
List<HashMap<String, String>> userProfiles = null;
try{
/** Getting the parsed data as a List construct */
userProfiles = userProfileJsonParser.parse(jObject);
}catch(Exception e){
Log.d("Exception",e.toString());
}
/** Keys used in Hashmap */
String[] from = { "name","screen_name"};
/** Ids of views in listview_layout */
int[] to = { R.id.name,R.id.screen_name};
SimpleAdapter adapter = new SimpleAdapter(UserProfileActivity.this, userProfiles, R.layout.friends_list_items_layout, from, to);
return adapter;
}
/** Invoked by the Android system on "doInBackground" is executed completely */
/** This will be executed in ui thread */
@Override
protected void onPostExecute(final SimpleAdapter adapter) {
dialoglist.setAdapter(adapter);
builder.setView(dialoglist);
if (!isDialogBoxOpen)
{
isDialogBoxOpen = true;
final Dialog dialog = builder.create();
dialog.show();
}
}
}
稍后当用户滚动listview时，它会执行另一个异步方法来加载更多数据。
dialoglist.setOnScrollListener(new OnScrollListener() {
private int currentVisibleItemCount;
private int currentScrollState;
private int currentFirstVisibleItem;
private int totalItem;
@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
// TODO Auto-generated method stub
int threshold = 1;
int count = dialoglist.getCount();
if (scrollState == SCROLL_STATE_IDLE) {
if (dialoglist.getLastVisiblePosition() >= count
- threshold) {
// Execute LoadMoreDataTask AsyncTask
new LoadMoreDataTask().execute();
}
}
this.currentScrollState = scrollState;
this.isScrollCompleted();
}
@Override
public void onScroll(AbsListView view, int firstVisibleItem,
int visibleItemCount, int totalItemCount) {
// TODO Auto-generated method stub
this.currentFirstVisibleItem = firstVisibleItem;
this.currentVisibleItemCount = visibleItemCount;
this.totalItem = totalItemCount;
}
private void isScrollCompleted() {
if (totalItem - currentFirstVisibleItem == currentVisibleItemCount
&& this.currentScrollState == SCROLL_STATE_IDLE) {
/** To do code here*/
}
}
});
}
private class LoadMoreDataTask extends AsyncTask<Void, Void, Void> {
@Override
protected Void doInBackground(Void... params) {
MyApiClients apiclients = new MyApiClients(session);
apiclients.getFriendsListService().show(userID, userName, nextCursor, countForList, new Callback<Response>() {
@Override
public void success(Result<Response> result) {
BufferedReader reader = null;
StringBuilder sb = new StringBuilder();
try {
reader = new BufferedReader(new InputStreamReader(result.response.getBody().in()));
String line;
while ((line = reader.readLine()) != null) {
sb.append(line);
}
} catch (IOException e) {
e.printStackTrace();
}
String jsonResult = sb.toString();
try {
JSONObject objResult = new JSONObject(jsonResult);
nextCursor = Long.parseLong (objResult.getString("next_cursor"));
ListViewLoaderTask listViewLoaderTask = new ListViewLoaderTask();
listViewLoaderTask.execute(jsonResult);
} catch (JSONException e) {
e.printStackTrace();
}
}
@Override
public void failure(Exception e) {
}
});
return null;
}
@Override
protected void onPostExecute(Void result) {
}
}
最后，当我们加载更多数据时，我再次调用listViewLoaderTask来绑定来自服务的检索数据。
它有效但有一些问题。当提醒数据到来时（5行）对话框变小。有时当我点击文本视图时，它不会打开对话框。
问题1：如何使我的对话框稳定。是自定义对话效率解决方案。
问题2：我使用异步方法进行此操作。你认为我的使用对吗？你为我的这项任务提供了哪些最佳实践方法？