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我有兩個片段片段A和片段B.在兩個片段Iam中使用asynctask並在後臺運行一些函數。這些函數（用於解析XML和填充列表視圖）。當我啓動兩個片段中的應用函數時都運行在同一時間。所以應用程序變得緩慢。 我需要的是首先在片段A中運行函數。片段B中的函數只有在完成片段B中的函數後才能啓動。。我該如何實現？請提前一些一扶me.Thanks .....如何在Android的碎片背景中運行函數？
片段A =>
public class A extends Fragment {
static String urls;
// XML node keys
static final String KEY_HEAD = "item"; // parent node
// static final String KEY_TITLE = "title";
static final String KEY_DATE = "pubDate";
public static String headflag = "";
int f = 0;
ListView list;
KeralaAdapter adapter;
ProgressBar loading;
ArrayList<HashMap<String, String>> newsList;
public static Kerala classnam;
public static String[] Title;
public static String[] Description;
public static String[] Tit;
public static String[] Tit2;
public static String[] Desc;
public static String[] Desc2;
public static String[] image;
public static String[] Date;
public static String[] Flash;
public static String[] Fl;
public static String[] Fl2;
public static NodeList nl;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflating layout
View v = inflater.inflate(R.layout.kerala_fragment, container, false);
// We obtain layout references
return v;
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
// We set clear listener
if (Headlines.headflag == "malayalam") {
urls = "http://www.abc.com/rssfeeds/17/1/rss.xml";
}
if (Headlines.headflag == "english") {
urls = "http://www.abc.com/en/rssfeeds/1/latest/rss.xml";
}
loading = (ProgressBar) getActivity().findViewById(R.id.loading);
new ProgressAsyncTask().execute();
}
public void populate_listview() {
newsList = new ArrayList<HashMap<String, String>>();
String MarqueeStr = "";
for (int i = 0; i < nl.getLength(); i++) {
// creating new HashMap
HashMap<String, String> map = new HashMap<String, String>();
Element e = (Element) nl.item(i);
// map.put(KEY_DATE, parser.getValue(e, KEY_DATE));
newsList.add(map);
}
}
public void StartProgress() {
new ProgressAsyncTask().execute();
}
public class ProgressAsyncTask extends AsyncTask<Void, Integer, Void> {
int myProgress;
@Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
myProgress = 0;
}
@Override
protected void onPostExecute(Void result) {
// TODO Auto-generated method stub
super.onPostExecute(result);
list = (ListView) getActivity().findViewById(R.id.list2);
// Getting adapter by passing xml data ArrayList
adapter = new KeralaAdapter(getActivity(), newsList);
list.setAdapter(adapter);
loading.setVisibility(View.INVISIBLE);
list.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
Intent myintent = new Intent(
"com.madhyamam.malayalam2keralapodcast.PODCAST");
Bundle mybundle = new Bundle();
mybundle.putInt("number", position);
myintent.putExtras(mybundle);
startActivity(myintent);
}
});
}
@Override
protected Void doInBackground(Void... arg0) {
// TODO Auto-generated method stub
getActivity().finishActivity(5);
parse(); //Here is the first function in fragment A
if (Title != null) {
populate_listview(); //Second function
}
return null;
}
@Override
protected void onProgressUpdate(Integer... values) {
// TODO Auto-generated method stub
}
}
public void parse() {
//parsing done here....
}
}
片段B =>
public class B extends Fragment {
static String urls;
// XML node keys
static final String KEY_HEAD = "item"; // parent node
// static final String KEY_TITLE = "title";
static final String KEY_DATE = "pubDate";
public static String headflag = "";
int f = 0;
ListView list;
NationalAdapter adapter;
ProgressBar loading;
ArrayList<HashMap<String, String>> newsList;
public static National classnam;
public static String[] Title;
public static String[] Description;
public static String[] Tit;
public static String[] Tit2;
public static String[] Desc;
public static String[] Desc2;
public static String[] image;
public static String[] Date;
public static String[] Flash;
public static String[] Fl;
public static String[] Fl2;
public static NodeList nl;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflating layout
View v = inflater.inflate(R.layout.national_fragment, container, false);
// We obtain layout references
return v;
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
// We set clear listener
if (Headlines.headflag == "malayalam") {
urls = "http://www.abc.com/rssfeeds/18/1/rss.xml";
}
if (Headlines.headflag == "english") {
urls = "http://www.abc.com/en/rssfeeds/2/latest/rss.xml";
}
loading = (ProgressBar) getActivity().findViewById(R.id.loading2);
new ProgressAsyncTask().execute();
}
public void populate_listview() {
newsList = new ArrayList<HashMap<String, String>>();
String MarqueeStr = "";
for (int i = 0; i < nl.getLength(); i++) {
// creating new HashMap
HashMap<String, String> map = new HashMap<String, String>();
Element e = (Element) nl.item(i);
// map.put(KEY_DATE, parser.getValue(e, KEY_DATE));
newsList.add(map);
}
}
public void StartProgress() {
new ProgressAsyncTask().execute();
}
public class ProgressAsyncTask extends AsyncTask<Void, Integer, Void> {
int myProgress;
@Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
myProgress = 0;
}
@Override
protected void onPostExecute(Void result) {
// TODO Auto-generated method stub
super.onPostExecute(result);
list = (ListView) getActivity().findViewById(R.id.list3);
// Getting adapter by passing xml data ArrayList
adapter = new NationalAdapter(getActivity(), newsList);
list.setAdapter(adapter);
loading.setVisibility(View.INVISIBLE);
list.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
Intent myintent = new Intent(
"com.madhyamam.malayalam2nationalpodcast.PODCAST");
Bundle mybundle = new Bundle();
mybundle.putInt("number", position);
myintent.putExtras(mybundle);
startActivity(myintent);
}
});
}
@Override
protected Void doInBackground(Void... arg0) {
// TODO Auto-generated method stub
parse(); //First function in fragment B
if (Title != null) {
populate_listview(); // Second function in fragment B
}
return null;
}
@Override
protected void onProgressUpdate(Integer... values) {
// TODO Auto-generated method stub
}
}
public void parse() {
//parsing done here....
}
}
而且主要活動=>
public class MainActivity extends SlidingMenuActivity {
private LinearLayout MenuList;
private Button btnToggleMenuList;
private int screenWidth;
private boolean isExpanded;
private ViewPager mViewPager;
private ProgressDialog pd;
TextView settings, headlines, kerala, national, international, sports,
tech, enter, bus, hotwheels, gulf;
static TextView flashnews;
public static int stopflag = 0;
HorizontalScrollView scroll;
private ListView listView;
static int currentRotation;
public PagerTabStrip pagerTabStrip;
@Override
public void onCreate(Bundle savedInstanceState) {
Context context = getApplicationContext();
setLayoutIds(R.layout.slidingtab, R.layout.main);
setAnimationDuration(300);
super.onCreate(savedInstanceState);
btnToggleMenuList = (Button) findViewById(R.id.BtnSlide);
btnToggleMenuList.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
toggleMenu();
startanim();
}
});
SharedPreferences mlmprf = getSharedPreferences("malayalam",
MODE_PRIVATE);
final SharedPreferences.Editor mlmedit = mlmprf.edit();
if (mlmprf.getBoolean("enable", true)) {
Headlines.headflag = "malayalam";
} else {
Headlines.headflag = "english";
}
flashnews = (TextView) findViewById(R.id.flashs);
flashnews.setSelected(true);
flashnews.setEllipsize(TruncateAt.MARQUEE);
flashnews.setHorizontallyScrolling(true);
flashnews.setSingleLine(true);
flashnews.setLines(1);
;
settings = (Button) findViewById(R.id.settings);
headlines = (TextView) findViewById(R.id.headlines);
kerala = (TextView) findViewById(R.id.kerala);
national = (TextView) findViewById(R.id.national);
international = (TextView) findViewById(R.id.international);
sports = (TextView) findViewById(R.id.sports);
tech = (TextView) findViewById(R.id.tech);
gulf = (TextView) findViewById(R.id.gulf);
enter = (TextView) findViewById(R.id.entertainment);
bus = (TextView) findViewById(R.id.business);
hotwheels = (TextView) findViewById(R.id.hotwheels);
Typeface tf = Typeface.createFromAsset(getAssets(), "fonts/kozuka.otf");
headlines.setTypeface(tf);
kerala.setTypeface(tf);
national.setTypeface(tf);
international.setTypeface(tf);
sports.setTypeface(tf);
tech.setTypeface(tf);
gulf.setTypeface(tf);
enter.setTypeface(tf);
bus.setTypeface(tf);
hotwheels.setTypeface(tf);
pagerTabStrip = (PagerTabStrip) findViewById(R.id.pager_title_strip);
pagerTabStrip.setDrawFullUnderline(true);
pagerTabStrip.setTabIndicatorColor(Color.rgb(3, 158, 203));
headlines.setPressed(true);
// We get UI references
mViewPager = (ViewPager) findViewById(R.id.viewpager);
// We set pager adapter
mViewPager.setAdapter(new MyAdapter(this));
mViewPager.setOffscreenPageLimit(9);
// We set receiver button listener
}
protected void startanim() {
// TODO Auto-generated method stub
RotateAnimation anim = new RotateAnimation(currentRotation,
currentRotation + 180, Animation.RELATIVE_TO_SELF, 0.5f,
Animation.RELATIVE_TO_SELF, 0.5f);
currentRotation = (currentRotation + 180) % 360;
anim.setInterpolator(new LinearInterpolator());
anim.setDuration(400);
anim.setFillEnabled(true);
anim.setFillAfter(true);
// Start animating the image
btnToggleMenuList.startAnimation(anim);
}
/**
* Adapter for ViewPAger that manages background interactions with fragments
*/
private class MyAdapter extends FragmentPagerAdapter {
private Context mContext;
private String[] frags = { A.class.getName(),
B.class.getName()};
public MyAdapter(FragmentActivity activity) {
super(activity.getSupportFragmentManager());
mContext = activity;
}
@Override
public Fragment getItem(int pos) {
return Fragment.instantiate(mContext, frags[pos]);
}
@Override
public int getCount() {
return frags.length;
}
@Override
public CharSequence getPageTitle(int pos) {
if (pos == 0)
return "A";
if (pos == 1)
return "B";
else
return null;
}
}
}
'AsyncTask'不是網絡工作的最佳場所。在隊列中處理網絡背景可以做的一件事是例如使用IntentService並將所有邏輯移動到那裏。使用網絡請求服務是Android的最佳實踐。您可以查看「Google I/O 2010 - Android REST客戶端應用程序」視頻。我認爲它會給你一些想法。 – Evos