我需要实现两个选项卡选项。1）顶级站 2）我的站 我使用标签主机的片段活动。我知道应该使用操作栏，但根据 psd 我需要在底部显示选项卡选项，所以我使用了 tabhost，因为我不知道如何在屏幕底部显示操作栏它完成了。在我的所有片段中，我正在调用 Web 服务并解析 json 响应并在 lisview 中安排响应。我已经在片段的 oncreaview 中编写了服务端通信代码。我面临的问题是，当我从登录活动片段 oncreateview 切换到我的片段活动时，没有被调用，因此我的列表视图不会出现。但是当我更改标签时，它开始出现。我放了日志，发现调用活动时没有调用片段的oncreatview。
这是 fragmentActivity 的代码： 现在我只使用了两个片段。
public class AwesomeActivityNew extends FragmentActivity implements
TabHost.OnTabChangeListener {
private TabHost mTabHost;
private HashMap mapTabInfo = new HashMap<String, TabInfo>();
private TabInfo mLastTab = null;
public class TabInfo {
private String tag;
private Class<?> clss;
private Bundle args;
private Fragment fragment;
TabInfo(String tag, Class<?> clazz, Bundle args) {
this.tag = tag;
this.clss = clazz;
this.args = args;
}
}
class TabFactory implements TabContentFactory {
private final Context mContext;
/**
*
* @param context
*/
public TabFactory(Context context) {
mContext = context;
}
/**
* (non-Javadoc)
*
* @see android.widget.TabHost.TabContentFactory#createTabContent(java.lang.String)
*/
public View createTabContent(String tag) {
View v = new View(mContext);
return v;
}
}
/**
* (non-Javadoc)
*
* @see android.support.v.app.FragmentActivity#onCreate(android.os.Bundle)
*/
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Step : Inflate layout
setContentView(R.layout.maintab_new);
// Step : Setup TabHost
initialiseTabHost(savedInstanceState);
if (savedInstanceState != null) {
mTabHost.setCurrentTabByTag(savedInstanceState.getString("tab")); // set
// the
// tab
// as
// per
// the
// saved
// state
}
}
/**
* (non-Javadoc)
*
* @see android.support.v.app.FragmentActivity#onSaveInstanceState(android.os.Bundle)
*/
protected void onSaveInstanceState(Bundle outState) {
outState.putString("tab", mTabHost.getCurrentTabTag()); // save the tab
// selected
super.onSaveInstanceState(outState);
}
/**
*
* Step : Setup TabHost
*/
private void initialiseTabHost(Bundle args) {
mTabHost = (TabHost) findViewById(android.R.id.tabhost);
mTabHost.setup();
TabInfo tabInfo = null;
AwesomeActivityNew.addTab(this, this.mTabHost, this.mTabHost
.newTabSpec("Tab2").setIndicator("Tab2 "),
(tabInfo = new TabInfo("Tab2", TopStation.class, args)));
this.mapTabInfo.put(tabInfo.tag, tabInfo);
AwesomeActivityNew.addTab(this, this.mTabHost, this.mTabHost
.newTabSpec("Tab3").setIndicator("My station", getResources().getDrawable( R.drawable.star )),
(tabInfo = new TabInfo("Tab3", MyStation.class, args)));
this.mapTabInfo.put(tabInfo.tag, tabInfo);
// Default to first tab
this.onTabChanged("Tab");
//
mTabHost.setOnTabChangedListener(this);
}
/**
*
* @param activity
*
* @param tabHost
*
* @param tabSpec
*
* @param clss
*
* @param args
*/
private static void addTab(AwesomeActivityNew activity, TabHost tabHost,
TabHost.TabSpec tabSpec, TabInfo tabInfo) {
// Attach a Tab view factory to the spec
tabSpec.setContent(activity.new TabFactory(activity));
String tag = tabSpec.getTag();
// Check to see if we already have a fragment for this tab, probably
// from a previously saved state. If so, deactivate it, because our
// initial state is that a tab isn't shown.
tabInfo.fragment = activity.getSupportFragmentManager()
.findFragmentByTag(tag);
if (tabInfo.fragment != null && !tabInfo.fragment.isDetached()) {
FragmentTransaction ft = activity.getSupportFragmentManager()
.beginTransaction();
ft.detach(tabInfo.fragment);
ft.commit();
activity.getSupportFragmentManager().executePendingTransactions();
}
tabHost.addTab(tabSpec);
}
/**
* (non-Javadoc)
*
* @see android.widget.TabHost.OnTabChangeListener#onTabChanged(java.lang.String)
*/
public void onTabChanged(String tag) {
TabInfo newTab = (TabInfo) this.mapTabInfo.get(tag);
if (mLastTab != newTab) {
FragmentTransaction ft = this.getSupportFragmentManager()
.beginTransaction();
if (mLastTab != null) {
if (mLastTab.fragment != null) {
ft.detach(mLastTab.fragment);
}
}
if (newTab != null) {
if (newTab.fragment == null) {
newTab.fragment = Fragment.instantiate(this,
newTab.clss.getName(), newTab.args);
ft.add(android.R.id.tabcontent, newTab.fragment, newTab.tag);
} else {
ft.attach(newTab.fragment);
}
}
mLastTab = newTab;
ft.commit();
this.getSupportFragmentManager().executePendingTransactions();
}
}
}
这是片段的代码：
public class TopStation extends Fragment {
boolean jsonloadflag = false;
// int count = 0;
int currentpage = 0;
ListView ls;
JSONArray jsonarray;
Downloader downloader;
JSONLoader jsonloader;
MyCustomadapter adp;
int totalpages = 0;
TextView page;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// HttpClient client = new DefaultHttpClient();
// HttpPost post = new
// HttpPost("http://eluminoustechnologies.net/webapp/services/toptenstations.php");
}
@Override
public void onAttach(Activity activity) {
// TODO Auto-generated method stub
super.onAttach(activity);
if (!jsonloadflag) {
jsonloader = new JSONLoader();
jsonloader.execute(getActivity().getString(
R.string.web_root_service)
+ getActivity().getString(+R.string.TOPTEN_STATION_URL));
}
Log.e("onattach top station called","true");
}
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// count = 0;
//Log.e("oncreate view top station called","true");
// Inflate the layout for this fragment
// return inflater.inflate(R.layout.afragment, container, false);
Log.e("inside top station oncrateview","true");
currentpage = 0;
View v = inflater.inflate(R.layout.top_station, container, false);
ls = (ListView) v.findViewById(R.id.listview_topstation);
page = (TextView) v.findViewById(R.id.textView2);
/*
* View v1 = inflater.inflate(R.layout.footer_mystation, null);
* ls.addFooterView(v1);
*/
Button nextbtn = (Button) v.findViewById(R.id.btnnext);
Button previousbtn = (Button) v.findViewById(R.id.btnprevious);
new Downloader(currentpage).execute();
nextbtn.setClickable(false);
previousbtn.setClickable(false);
nextbtn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
if (currentpage < totalpages) {
new Downloader(currentpage).execute();
currentpage += 1;
page.setText("Page " + currentpage);
}
}
});
previousbtn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
if (currentpage > 1) {
new Downloader(currentpage).execute();
currentpage -= 1;
page.setText("Page " + currentpage);
}
}
});
return v;
}
@Override
public void onPause() {
// TODO Auto-generated method stub
super.onPause();
}
class MyCustomadapter extends BaseAdapter {
ArrayList<HashMap<String, String>> data;
ArrayList<HashMap<String, Bitmap>> images;
public MyCustomadapter(ArrayList<HashMap<String, String>> ls,
ArrayList<HashMap<String, Bitmap>> listbitmap) {
this.data = ls;
this.images = listbitmap;
// this.data=imagename;
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return images.size();
}
@Override
public Object getItem(int arg0) {
// TODO Auto-generated method stub
return data.get(arg0);
}
@Override
public long getItemId(int arg0) {
// TODO Auto-generated method stub
return arg0;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
// Log.e("inside getview " + count, "true");
View row;
LayoutInflater inflater = getActivity().getLayoutInflater();
row = inflater.inflate(R.layout.list_row, null, false);
// grid=inflater.inflate(R.layout.gridrow, null);
ImageView stationimg = (ImageView) row
.findViewById(R.id.imageView1);
TextView stationname = (TextView) row.findViewById(R.id.textView1);
TextView description = (TextView) row.findViewById(R.id.textView2);
HashMap<String, String> map = data.get(position);
HashMap<String, Bitmap> imagemap = images.get(position);
stationname.setText(map.get("station_name"));
// Log.e("map data for desc", map.get("description"));
description.setText(map.get("description"));
if (imagemap.get("station_picture") != null)
stationimg.setImageBitmap(imagemap.get("station_picture"));
// stationimg.setBackgroundResource(dataimg[position]);
return (row);
}
}
private class Downloader extends AsyncTask<Void, Void, Void> {
int cpage = 0;
ProgressDialog dialog;
ArrayList<HashMap<String, String>> list = new ArrayList<HashMap<String, String>>();
ArrayList<HashMap<String, Bitmap>> listbitmap = new ArrayList<HashMap<String, Bitmap>>();
public Downloader(int page) {
this.cpage = page;
}
@Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
dialog = new ProgressDialog(getActivity());
dialog.show();
}
@Override
protected void onPostExecute(Void result) {
// TODO Auto-generated method stub
super.onPostExecute(result);
adp = new MyCustomadapter(list, listbitmap);
ls.setAdapter(adp);
adp.notifyDataSetChanged();
Log.e("onPostExecute called", "true");
Log.e("size of data list", "" + list.size());
Log.e("size of data list", "" + listbitmap.size());
dialog.dismiss();
}
@Override
protected Void doInBackground(Void... params) {
// TODO Auto-generated method stub
Log.e("do inbackground downloader of downloader called", "true");
if (jsonloadflag) {
for (int j = cpage * 4; j < cpage * 4 + 4
&& j < jsonarray.length(); j++) {
HashMap<String, String> map = new HashMap<String, String>();
HashMap<String, Bitmap> imagemap = new HashMap<String, Bitmap>();
JSONObject jsonobj;
try {
jsonobj = jsonarray.getJSONObject(j);
String station_id = jsonobj.getString("station_id");
String station_name = jsonobj.getString("station_name");
String station_picture = jsonobj
.getString("station_picture");
String description = jsonobj.getString("description");
map.put("station_id", station_id);
map.put("station_name", station_name);
// map.put("station_picture", station_picture);
map.put("description", description);
String imageurl = getActivity().getResources()
.getString(R.string.web_root)
+ getActivity().getResources().getString(
R.string.station_image_path)
+ station_picture.replace(" ", "%20");
try {
URL url = new URL(imageurl);
HttpURLConnection conn = (HttpURLConnection) url
.openConnection();
conn.setDoInput(true);
conn.connect();
InputStream is = conn.getInputStream();
Bitmap bmImg = BitmapFactory.decodeStream(is);
if (bmImg != null)
imagemap.put("station_picture", bmImg);
else {
Drawable myDrawable = getResources()
.getDrawable(R.drawable.ic_launcher);
Bitmap defaultimg = ((BitmapDrawable) myDrawable)
.getBitmap();
imagemap.put("station_picture", defaultimg);
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
// Log.e("station_id",station_id);
// Log.e("station_name", station_name);
// Log.e("station_picture",station_picture);
// Log.e("description", description);
// Log.e("counter is",""+count);
list.add(map);
listbitmap.add(imagemap);
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
// count += 5;
}
return null;
}
}
private class JSONLoader extends AsyncTask<String, Void, Void> {
JSONParser parser = new JSONParser();
@Override
protected void onPostExecute(Void result) {
// TODO Auto-generated method stub
super.onPostExecute(result);
if (jsonarray.length() > 0) {
page.setText("Page " + 1);
currentpage = 1;
}
}
@Override
protected Void doInBackground(String... params) {
// TODO Auto-generated method stub
Log.e("do in background of json loader called", "true");
if (!jsonloadflag) {
jsonarray = parser.getJSONarrayFromUrl(params[0]);
if (jsonarray.length() % 4 == 0)
totalpages = jsonarray.length() / 4;
else
totalpages = jsonarray.length() / 4 + 1;
// Log.e("url param", params[0]);
// Log.e("server side json", jsonarray.toString());
jsonloadflag = true;
}
return null;
}
}
}
请帮助我如何在我的片段活动启动时显示我的片段并加载包含选项卡主机和片段的服务端数据。