我从这里下载了实现 Google Places API 的源代码（可以从这里下载），但它只有一个基本的 ListView 但我想将可滑动的标签与之集成，所以我尝试了一切，最后尝试复制每一行每个文件都放入一个新项目中，当以某种方式消除大量错误后，LogCat 显示：
04-22 22:17:49.398: E/AndroidRuntime(12254): FATAL EXCEPTION: AsyncTask #1
04-22 22:17:49.398: E/AndroidRuntime(12254): java.lang.RuntimeException: An error occured while executing doInBackground()
这MainActivty.java:
package project.mad.travelmate;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Locale;
import project.mad.travelmate.Place;
import project.mad.travelmate.MainActivity;
import project.mad.travelmate.PlacesMapActivity;
import project.mad.travelmate.R;
import project.mad.travelmate.SinglePlaceActivity;
import project.mad.travelmate.MainActivity.LoadPlaces;
import project.mad.travelmate.AlertDialogManager;
import project.mad.travelmate.ConnectionDetector;
import project.mad.travelmate.GPSTracker;
import project.mad.travelmate.GooglePlaces;
import project.mad.travelmate.PlacesList;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.app.FragmentPagerAdapter;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.view.ViewPager;
import android.text.Html;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;
import android.widget.AdapterView.OnItemClickListener;
public class MainActivity extends ActionBarActivity implements
ActionBar.TabListener {
SectionsPagerAdapter mSectionsPagerAdapter;
ViewPager mViewPager;
// flag for Internet connection status
Boolean isInternetPresent = false;
// Connection detector class
ConnectionDetector cd;
// Alert Dialog Manager
AlertDialogManager alert = new AlertDialogManager();
// Google Places
GooglePlaces googlePlaces;
// Places List
PlacesList nearPlaces;
// GPS Location
GPSTracker gps;
// Button
Button btnShowOnMap;
// Progress dialog
ProgressDialog pDialog;
// Places Listview
ListView lv;
// ListItems data
ArrayList<HashMap<String, String>> placesListItems = new ArrayList<HashMap<String,String>>();
// KEY Strings
public static String KEY_REFERENCE = "reference"; // id of the place
public static String KEY_NAME = "name"; // name of the place
public static String KEY_VICINITY = "vicinity"; // Place area name
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Set up the action bar.
final ActionBar actionBar = getSupportActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
// Create the adapter that will return a fragment for each of the three
// primary sections of the activity.
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));
}
cd = new ConnectionDetector(getApplicationContext());
// Check if Internet present
isInternetPresent = cd.isConnectingToInternet();
if (!isInternetPresent) {
// Internet Connection is not present
alert.showAlertDialog(MainActivity.this, "Internet Connection Error",
"Please connect to working Internet connection", false);
// stop executing code by return
return;
}
// creating GPS Class object
gps = new GPSTracker(this);
// check if GPS location can get
if (gps.canGetLocation()) {
Log.d("Your Location", "latitude:" + gps.getLatitude() + ", longitude: " + gps.getLongitude());
} else {
// Can't get user's current location
alert.showAlertDialog(MainActivity.this, "GPS Status",
"Couldn't get location information. Please enable GPS",
false);
// stop executing code by return
return;
}
// Getting listview
lv = (ListView) findViewById(R.id.list);
// button show on map
//btnShowOnMap = (Button) findViewById(R.id.btn_show_map);
// calling background Async task to load Google Places
// After getting places from Google all the data is shown in listview
new LoadPlaces().execute();
/** Button click event for shown on map
btnShowOnMap.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
Intent i = new Intent(getApplicationContext(),
PlacesMapActivity.class);
// Sending user current geo location
i.putExtra("user_latitude", Double.toString(gps.getLatitude()));
i.putExtra("user_longitude", Double.toString(gps.getLongitude()));
// passing near places to map activity
i.putExtra("near_places", nearPlaces);
// staring activity
startActivity(i);
}
});
*/
/**
* ListItem click event
* On selecting a listitem SinglePlaceActivity is launched
* */
lv.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// getting values from selected ListItem
String reference = ((TextView) view.findViewById(R.id.reference)).getText().toString();
// Starting new intent
Intent in = new Intent(getApplicationContext(),
SinglePlaceActivity.class);
// Sending place refrence id to single place activity
// place refrence id used to get "Place full details"
in.putExtra(KEY_REFERENCE, reference);
startActivity(in);
}
});
}
/**
* Background Async Task to Load Google places
* */
@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 boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
@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 PlaceholderFragment (defined as a static inner class
// below).
return PlaceholderFragment.newInstance(position + 1);
}
@Override
public int getCount() {
// Show 3 total pages.
return 3;
}
@Override
public CharSequence getPageTitle(int position) {
Locale l = Locale.getDefault();
switch (position) {
case 0:
return getString(R.string.police).toUpperCase(l);
case 1:
return getString(R.string.hospital).toUpperCase(l);
case 2:
return getString(R.string.restaurant).toUpperCase(l);
}
return null;
}
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
private static final String ARG_SECTION_NUMBER = "section_number";
/**
* Returns a new instance of this fragment for the given section number.
*/
public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
public PlaceholderFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container,
false);
TextView textView = (TextView) rootView
.findViewById(R.id.section_label);
textView.setText(Integer.toString(getArguments().getInt(
ARG_SECTION_NUMBER)));
return rootView;
}
}
class LoadPlaces extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(MainActivity.this);
pDialog.setMessage(Html.fromHtml("<b>Search</b><br/>Loading Places..."));
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show();
}
/**
* getting Places JSON
* */
protected String doInBackground(String... args) {
// creating Places class object
googlePlaces = new GooglePlaces();
try {
String types = null;
//String types = "police|hospital|train_station"; // Listing places only cafes, restaurants
// Radius in meters - increase this value if you don't find any places
double radius = 10000; // 1000 meters
// get nearest places
nearPlaces = googlePlaces.search(gps.getLatitude(),
gps.getLongitude(), radius, types);
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
protected void onPostExecute(String file_url) {
// dismiss the dialog after getting all products
pDialog.dismiss();
// updating UI from Background Thread
runOnUiThread(new Runnable() {
public void run() {
/**
* Updating parsed Places into LISTVIEW
* */
// Get json response status
String status = nearPlaces.status;
// Check for all possible status
if(status.equals("OK")){
// Successfully got places details
if (nearPlaces.results != null) {
// loop through each place
for (Place p : nearPlaces.results) {
HashMap<String, String> map = new HashMap<String, String>();
// Place reference won't display in listview - it will be hidden
// Place reference is used to get "place full details"
map.put(KEY_REFERENCE, p.reference);
// Place name
map.put(KEY_NAME, p.name);
// adding HashMap to ArrayList
placesListItems.add(map);
}
// list adapter
ListAdapter adapter = new SimpleAdapter(MainActivity.this, placesListItems,
R.layout.list_item,
new String[] { KEY_REFERENCE, KEY_NAME}, new int[] {
R.id.reference, R.id.name });
// Adding data into listview
lv.setAdapter(adapter);
}
}
else if(status.equals("ZERO_RESULTS")){
// Zero results found
alert.showAlertDialog(MainActivity.this, "Near Places",
"Sorry no places found. Try to change the types of places",
false);
}
else if(status.equals("UNKNOWN_ERROR"))
{
alert.showAlertDialog(MainActivity.this, "Places Error",
"Sorry unknown error occured.",
false);
}
else if(status.equals("OVER_QUERY_LIMIT"))
{
alert.showAlertDialog(MainActivity.this, "Places Error",
"Sorry query limit to google places is reached",
false);
}
else if(status.equals("REQUEST_DENIED"))
{
alert.showAlertDialog(MainActivity.this, "Places Error",
"Sorry error occured. Request is denied",
false);
}
else if(status.equals("INVALID_REQUEST"))
{
alert.showAlertDialog(MainActivity.this, "Places Error",
"Sorry error occured. Invalid Request",
false);
}
else
{
alert.showAlertDialog(MainActivity.this, "Places Error",
"Sorry error occured.",
false);
}
}
});
}
}
}
完整的源代码在这里。请任何人帮助我，或告诉我一种在此应用程序中集成可滑动标签或导航抽屉的方法。
提前致谢