我正在开发一个shoutcast应用程序（除了默认的MediaPlayer的流质量问题），它使用listFragment存储应用程序处于活动状态的歌曲信息。
到目前为止，我在该片段上有一个按钮，我已经添加了一个onClickListener来通过AysncTask执行HTTP Get Request。这很完美。 但是我显然不想浪费额外的空间，包括刷新列表的按钮。所以我一直在尝试实现一个定时器，它可以执行listFragment的更新功能，无论用户当前正在查看哪个片段。
*更新功能会检查列表顶部的重复项，因此我并不担心组织数据。
*截至目前，打开的第一个片段有控制MediaPlayer对象的按钮，第二个是listFragment。
这些是我的java文件。我对Android开发很新，所以任何解决方案的例子都很棒。
import java.io.IOException;
import java.util.Locale;
import android.annotation.SuppressLint;
import android.app.ActionBar;
import android.app.Application;
import android.app.FragmentTransaction;
//import android.app.ListFragment;
import android.os.Bundle;
import android.os.PowerManager;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.app.ListFragment;
import android.support.v4.app.NavUtils;
import android.support.v4.view.ViewPager;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnTouchListener;
import android.view.ViewGroup;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import android.app.Activity;
import android.content.Context;
import android.content.res.Configuration;
import android.media.AudioManager;
import android.media.AudioManager.OnAudioFocusChangeListener;
import android.media.MediaPlayer;
import android.media.MediaPlayer.OnInfoListener;
import android.media.MediaPlayer.OnPreparedListener;
import android.net.Uri;
import android.net.wifi.WifiManager;
import android.net.wifi.WifiManager.WifiLock;
import android.util.Log;
import android.widget.Button;
public class MainActivity extends FragmentActivity implements ActionBar.TabListener {
/**
* The {@link android.support.v4.view.PagerAdapter} that will provide
* fragments for each of the sections. We use a
* {@link android.support.v4.app.FragmentPagerAdapter} derivative, which
* will keep every loaded fragment in memory. If this becomes too memory
* intensive, it may be best to switch to a
* {@link android.support.v4.app.FragmentStatePagerAdapter}.
*/
SectionsPagerAdapter mSectionsPagerAdapter;
/**
* The {@link ViewPager} that will host the section contents.
*/
ViewPager mViewPager;
private MediaPlayer mp;
int MediaState = 0; //idle
@SuppressLint("ShowToast")
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Set up the action bar.
final ActionBar actionBar = getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
// Create the adapter that will return a fragment for each of the three
// primary sections of the app.
mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.pager);
mViewPager.setAdapter(mSectionsPagerAdapter);
// When swiping between different sections, select the corresponding
// tab. We can also use ActionBar.Tab#select() to do this if we have
// a reference to the Tab.
mViewPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
@Override
public void onPageSelected(int position) {
actionBar.setSelectedNavigationItem(position);
}
});
// For each of the sections in the app, add a tab to the action bar.
for (int i = 0; i < mSectionsPagerAdapter.getCount(); i++) {
// Create a tab with text corresponding to the page title defined by
// the adapter. Also specify this Activity object, which implements
// the TabListener interface, as the callback (listener) for when
// this tab is selected.
actionBar.addTab(
actionBar.newTab()
.setText(mSectionsPagerAdapter.getPageTitle(i))
.setTabListener(this));
}
Toast setup = Toast.makeText(getApplicationContext(), "Setting Up", Toast.LENGTH_SHORT);
setup.show();
//Audio manager
if(mp==null) //prevent creation of new media player for new instances of the views
{
mp = new MediaPlayer();
mp.setAudioStreamType(AudioManager.STREAM_MUSIC);
try{
mp.setAudioSessionId(0);
mp.setDataSource("http://130.191.35.35:8000");
mp.setWakeMode(getApplicationContext(), PowerManager.PARTIAL_WAKE_LOCK);
mp.setOnPreparedListener(new OnPreparedListener()
{
@Override
public void onPrepared(MediaPlayer arg0) {
// TODO Auto-generated method stub
//playStream(mViewPager);
//mp.start();
MediaState = 2; //prepared
Toast t = Toast.makeText(getApplicationContext(), "Ready to Go", Toast.LENGTH_SHORT);
t.show();
}
});
//on info listener not catching any of the info through logcat for live stream skipping audio is due to buffer underruns
//Should fix by using a stream proxy instead...not sure how to set one up
mp.setOnInfoListener(new OnInfoListener() {
@Override
public boolean onInfo(MediaPlayer mp, int what, int extra) {
if (what == MediaPlayer.MEDIA_INFO_BUFFERING_START) {
Toast t = Toast.makeText(getApplicationContext(), "Buffering", Toast.LENGTH_SHORT);
t.show();
} else if (what == MediaPlayer.MEDIA_INFO_BUFFERING_END) {
Toast t = Toast.makeText(getApplicationContext(), "Buffering Stopped", Toast.LENGTH_SHORT);
t.show();
} else if (what == 703)
{
Toast t = Toast.makeText(getApplicationContext(), "Problem!", Toast.LENGTH_SHORT);
t.show();
}
return false;
}
});
MediaState = 1; //initialized // or stopped
mp.prepareAsync();
MediaState = 6; //MediaPlayer is preparing pick a state that isn't used so nothing works until its prepared
}
catch(IOException ex)
{
Toast t = Toast.makeText(getApplicationContext(), "Problem", Toast.LENGTH_SHORT);
t.show();
}
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
// When the given tab is selected, switch to the corresponding page in
// the ViewPager.
mViewPager.setCurrentItem(tab.getPosition());
}
@Override
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
}
@Override
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
}
/**
* A {@link FragmentPagerAdapter} that returns a fragment corresponding to
* one of the sections/tabs/pages.
*/
public class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position) {
// getItem is called to instantiate the fragment for the given page.
// Return a DummySectionFragment (defined as a static inner class
// below) with the page number as its lone argument.
Fragment fragment;
if(position==0)
{
//returns the main page
fragment = new DummySectionFragment();
Bundle args = new Bundle();
args.putInt(DummySectionFragment.ARG_SECTION_NUMBER, position + 1);
fragment.setArguments(args);
}
else
{ //returns the listFragment
fragment = new SecondSectionFragment();
Bundle args = new Bundle();
fragment.setArguments(args);
}
return fragment;
}
@Override
public int getCount() {
// Show 3 total pages.
// Show 2 total pages
return 2;
}
@Override
public CharSequence getPageTitle(int position) {
Locale l = Locale.getDefault();
switch (position) {
case 0:
return getString(R.string.title_section1).toUpperCase(l);
case 1:
return getString(R.string.title_section2).toUpperCase(l);
case 2:
return getString(R.string.title_section3).toUpperCase(l);
}
return null;
}
}
/**
* The main screen's fragment
*/
public static class DummySectionFragment extends Fragment{
/**
* The fragment argument representing the section number for this
* fragment.
*/
public static final String ARG_SECTION_NUMBER = "section_number";
public DummySectionFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main_dummy, container, false);
return rootView;
}
}
public void playStream(View view) {
if(!mp.isPlaying())
{
if(MediaState==2)
{
mp.start();
Toast t = Toast.makeText(getApplicationContext(), "Play", Toast.LENGTH_SHORT);
t.show();
MediaState=3; // Media is now in started state
}
if(MediaState==1)
{
try
{
mp.prepare();
MediaState = 2; // Media is now prepared
mp.start();
Toast t = Toast.makeText(getApplicationContext(), "Play", Toast.LENGTH_SHORT);
t.show();
MediaState = 3; // Media is now in playing or started state
}
catch(IOException ex)
{
}
}
}
}
public void pauseStream(View view)
{
if(mp.isPlaying())
{
mp.pause();
Toast t = Toast.makeText(getApplicationContext(), "Pause", Toast.LENGTH_SHORT);
t.show();
MediaState = 2; // Media is now in paused state
}
}
public void stopStream(View view)
{
mp.stop();
Toast t = Toast.makeText(getApplicationContext(), "Stop", Toast.LENGTH_SHORT);
t.show();
MediaState = 1;
}
@Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
//prevent odd echoing for media player when screen rotates something to do with the activity being destroyed
}
}
import java.io.IOException;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;
import android.app.Activity;
import android.content.Context;
import android.net.ParseException;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Looper;
import android.support.v4.app.ListFragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.Toast;
public class SecondSectionFragment extends ListFragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
public static final String ARG_SECTION_NUMBER = "section_number";
public SecondSectionFragment() {
}
String[] values = new String[] {"Welcome!"};
ArrayAdapter<String> adapter;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.second_main_dummy, container, false);
Button refreshButton = (Button)rootView.findViewById(R.id.addBtn);
refreshButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
findItem();
}
});
adapter = new ArrayAdapter<String>(getActivity(),
android.R.layout.simple_list_item_1, values);
setListAdapter(adapter);
setupTimer();
return rootView;
}
@Override
public void onListItemClick(ListView l, View v, int position, long id)
{
String text = adapter.getItem(position);
customToast(text);
}
public void customToast(String text)
{
Toast t = Toast.makeText(this.getActivity().getApplicationContext(), text, Toast.LENGTH_SHORT);
t.show();
}
public void addItem(String[] texts)
{
for(int t=0;t<texts.length;t++)
{
addItem(texts[t]);
}
}
public void addItem(String text)
{
String[] prev = new String[values.length];
prev = values.clone();
values = new String[prev.length+1];
values[0]=text;
for(int i=1;i<values.length;i++)
{
values[i]=prev[i-1];
}
adapter = new ArrayAdapter<String>(getActivity(),
android.R.layout.simple_list_item_1, values);
setListAdapter(adapter);
adapter.notifyDataSetChanged();
}
class HTTPRequest extends AsyncTask<Void, Void, String> {
@Override
protected String doInBackground(Void... params) {
try {
HttpGet httpRequest = new HttpGet( "http://_____/___.php?q="+Math.random());
HttpClient httpclient = new DefaultHttpClient();
HttpResponse response = httpclient.execute(httpRequest);
int code = response.getStatusLine().getStatusCode();
if(code!=404)
{
String responseBody = EntityUtils.toString(response.getEntity());
responseBody = responseBody.replace("</body></html>","");
return responseBody;
}
return "404 Error";
} catch (Exception e) {
return "Exception";
}
}
protected void onPostExecute(String text) {
if(!text.contains(adapter.getItem(0)))
{
addItem(text);
}
else
{
customToast(adapter.getItem(0));
}
}
}
public void findItem()
{
new HTTPRequest().execute();
}
public void setupTimer()
{
//Not sure if this would be the correct place to start up a timer
}
}
答案 0 :(得分：0)
如果这仍然有效。我确实有这样的实时更新解决方案。
private final Handler mHandler = new Handler();
private final Runnable mRunnable = new Runnable() {
@Override
public void run() {
mHandler.removeCallbacks(mRunnable);
// DO here something like your findItem()
mHandler.postDelayed(mRunnable, TIMEOUT);
}
};
public void setupTimer() {
if (mHandler != null) {
mHandler.removeCallbacks(mRunnable);
mHandler.postDelayed(mRunnable, TIMEOUT);
}
}
从onResume（）调用你的setupTimer（） 在你的onPause（）添加
if (mHandler != null) {
mHandler.removeCallbacks(mRunnable);
}