使用Activity（不是ListActivity）和asyncTask onPostExecute（）android显示listView

Question

当我运行我的应用程序时，它会崩溃。实际上我注意到在list.setAdapter(adapter);中写PostExecute()时会出现问题。谁能帮我？感谢。

在Searchbykey活动中，用户可以从列表

中选择一些项目

public class Searchbykey extends SherlockActivity {

    ActionBar actionbar;
    ListView listView;
    ArrayAdapter<String> adapter;
    double latitude, longitude;
    public static ArrayList<HashMap<String, String>> xml_results;
    public ProgressDialog progressDialog; 
    Intent intentResults ;
    int k=0;
    //XML node keys
    static final String KEY_ENV = "environment"; // parent node
    static final String KEY_TITLE = "title";
    static final String KEY_FEED = "feed";
    static final String KEY_ID = "id";
    static final String KEY_LAT = "lat";
    static final String KEY_LON = "lon";
    static final String KEY_DIF_LAT = "dif lat";
    static final String KEY_DIF_LON = "dif lon";
    static final String KEY_NAME = "name";
    static final String KEY_DESC = "description";

    String[] countries = new String[] {
            "India",
            "Pakistan",
            "Sri Lanka",
            "China",
            "Bangladesh",
            "Nepal",
            "Afghanistan",
            "North Korea",
            "South Korea",
            "Japan"
    };

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.keylist);

        actionbar=getSupportActionBar();
        actionbar.setTitle("Search by keyword(s)");

        //-------Get the location that calculate from previus acrivity. Before that activity start. 
        Bundle extras = getIntent().getExtras();
        if (extras == null) 
        {
            System.out.println("None");
        }

        //Get data via the key
        latitude = extras.getDouble("latitude");
        longitude = extras.getDouble("longitude");


        //----------I have a location service that detect the location and send a broadcast msg. So here I declare a register to listen the broadcast msg for location

        IntentFilter filter = new IntentFilter("xxx.yyy.intent.action.LOCATION");
        this.registerReceiver(new LocationReceiver(), filter);

        //The checkbox for the each item is specified by the layout android.R.layout.simple_list_item_multiple_choice
        ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_multiple_choice, countries);

        //Getting the reference to the listview object of the layout
        listView = (ListView) findViewById(R.id.ListView);

        //Setting adapter to the listview
        listView.setAdapter(adapter);

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {

        getSupportMenuInflater().inflate(R.menu.keywordmenu, menu);

        (menu.findItem(R.id.search)).setIcon(R.drawable.action_search);
        (menu.findItem(R.id.clear)).setIcon(R.drawable.abs__ic_clear);

        //return(true);
        return super.onCreateOptionsMenu(menu);
    }

    public boolean onOptionsItemSelected(MenuItem item) {

        switch (item.getItemId()) {
            case R.id.search:

            //-----------Call new activity that appears the search result   
            intentResults = new Intent (this, Keysearch_results.class);
            startActivity(intentResults);

            break;
        case R.id.clear:
            ClearSelections();
        break;
        }
        return true;

    }    
}

//-----The Keysearch_results is the activity that i want to take info from url (xml parser) and appear the result of search
public class Keysearch_results extends SherlockActivity {

    //XML node keys
    static final String KEY_ENV = "environment"; // parent node
    static final String KEY_TITLE = "title";
    static final String KEY_FEED = "feed";
    static final String KEY_ID = "id";
    static final String KEY_LAT = "lat";
    static final String KEY_LON = "lon";
    static final String KEY_DIF_LAT = "dif lat";
    static final String KEY_DIF_LON = "dif lon";
    static final String KEY_NAME = "name";
    static final String KEY_DESC = "description";


    public ProgressDialog progressDialog; 
    public ArrayList<HashMap<String, String>> listItems;

    //Menu Bar
    ActionBar actionbar;

    //List
    ListView listView;
    ArrayAdapter<String> adapter;

    //User Location
    double latitude, longitude;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.results);

        //Appear action bar
        actionbar=getSupportActionBar();
        actionbar.setTitle("Results");


        //Getting the reference to the listview object of the layout
        listView = (ListView) findViewById(R.id.ResList);

        ListAdapter adapter = new SimpleAdapter(this, listItems,
                R.layout.result_row,
                new String[] { "feed", "dif lat",}, new int[] {
                        R.id.name, R.id.dif});

   new YourDownload().execute();

    }


private class YourDownload extends AsyncTask<Void, Void, Integer> {

     // private String Content;


     @Override
     protected Integer doInBackground(Void... params) {

         if(isOnline()){
            listItems.clear();   
            int i; 
            HashMap<String, String> map = null; 
            XMLParser parser = new XMLParser();
            //getting XML
            String xml = null ;
          DefaultHttpClient client = new DefaultHttpClient();
            HttpGet request = new HttpGet();
            try {
                request.setURI(new URI("http://api.cosm.com/v2/feeds.xml?&key=Sov51TAorgtao6W_JuNodPN3KMqSAKxuZjFsblR3TUp4TT0g&lat=35.1446170529352&lon=33.3462524414062"));
            } catch (URISyntaxException e) {

                e.printStackTrace();
                System.out.print("http\n");
            }
            HttpResponse httpResponse = null;
            try {
                httpResponse = client.execute(request);
            } catch (ClientProtocolException e1) {

                e1.printStackTrace();
            } catch (IOException e1) {

                e1.printStackTrace();
            }
            HttpEntity httpEntity = httpResponse.getEntity();
            try {
                xml = EntityUtils.toString(httpEntity);
            } catch (ParseException e1) {
                e1.printStackTrace();
            } catch (IOException e1) {

                e1.printStackTrace();
            }


            //getting DOM element
            Document doc = parser.getDomElement(xml); 

            NodeList nl = doc.getElementsByTagName(KEY_ENV);
          //int size=nl.getLength(); 
            // looping through all item nodes <item>
            for (i = 0; i < nl.getLength(); i++) {
                // creating new HashMap
                map = new HashMap<String, String>();
                Element e = (Element) nl.item(i);
                // adding each child node to HashMap key => value
                map.put(KEY_FEED, parser.getValue(e, KEY_FEED));
                map.put(KEY_DIF_LAT, parser.getValue(e, KEY_LAT));
                map.put(KEY_DIF_LON, parser.getValue(e, KEY_LON));
                listItems.add(map);
            }
         }
         else{
            Toast.makeText(Keysearch_results.this, "No connection..", Toast.LENGTH_LONG).show();            
        }

            return 1;
        }

     @Override
     protected void onPostExecute(Integer result) {

         if(result==1 && listItems!=null)
         {

         listView.setAdapter(adapter);
         }
         progressDialog.dismiss();
         super.onPostExecute(result);
     } 

    }
}

列表布局：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

 <TextView android:id="@+id/name" 
     android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:padding="10dp"
    android:textAppearance="?android:attr/textAppearanceMedium"
    android:textStyle="bold"
    android:textSize="16sp" >
  </TextView>

   <TextView android:id="@+id/dif" 
   android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:padding="10dp"
    android:textAppearance="?android:attr/textAppearanceMedium"
    android:textStyle="bold"
    android:textSize="16sp" > </TextView>

   <TextView android:id="@+id/dd" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content"
    android:padding="10dp"
    android:textAppearance="?android:attr/textAppearanceMedium"
    android:textStyle="bold"
    android:textSize="16sp" >
  </TextView>


</LinearLayout>

错误：

    04-06 19:50:30.326: E/ActivityThread(795): Activity com.example.ioaaan.Searchbykey has leaked IntentReceiver com.example.ioaaan.Searchbykey$LocationReceiver@40cdb248 that was originally registered here. Are you missing a call to unregisterReceiver()?
    04-06 19:50:30.326: E/ActivityThread(795): android.app.IntentReceiverLeaked: Activity com.example.ioaaan.Searchbykey has leaked IntentReceiver com.example.ioaaan.Searchbykey$LocationReceiver@40cdb248 that was originally registered here. Are you missing a call to unregisterReceiver()?
    04-06 19:50:30.326: E/ActivityThread(795):  at android.app.LoadedApk$ReceiverDispatcher.<init>(LoadedApk.java:795)
    04-06 19:50:30.326: E/ActivityThread(795):  at android.app.LoadedApk.getReceiverDispatcher(LoadedApk.java:596)
    04-06 19:50:30.326: E/ActivityThread(795):  at android.app.ContextImpl.registerReceiverInternal(ContextImpl.java:1316)
    04-06 19:50:30.326: E/ActivityThread(795):  at android.app.ContextImpl.registerReceiver(ContextImpl.java:1296)
    04-06 19:50:30.326: E/ActivityThread(795):  at android.app.ContextImpl.registerReceiver(ContextImpl.java:1290)
    04-06 19:50:30.326: E/ActivityThread(795):  at android.content.ContextWrapper.registerReceiver(ContextWrapper.java:423)
    04-06 19:50:30.326: E/ActivityThread(795):  at com.example.ioaaan.Searchbykey.onCreate(Searchbykey.java:121)
    04-06 19:50:30.326: E/ActivityThread(795):  at android.app.Activity.performCreate(Activity.java:5104)
    04-06 19:50:30.326: E/ActivityThread(795):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
    04-06 19:50:30.326: E/ActivityThread(795):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
    04-06 19:50:30.326: E/ActivityThread(795):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
    04-06 19:50:30.326: E/ActivityThread(795):  at android.app.ActivityThread.access$600(ActivityThread.java:141)
    04-06 19:50:30.326: E/ActivityThread(795):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
    04-06 19:50:30.326: E/ActivityThread(795):  at android.os.Handler.dispatchMessage(Handler.java:99)
    04-06 19:50:30.326: E/ActivityThread(795):  at android.os.Looper.loop(Looper.java:137)
    04-06 19:50:30.326: E/ActivityThread(795):  at android.app.ActivityThread.main(ActivityThread.java:5041)
    04-06 19:50:30.326: E/ActivityThread(795):  at java.lang.reflect.Method.invokeNative(Native Method)
    04-06 19:50:30.326: E/ActivityThread(795):  at java.lang.reflect.Method.invoke(Method.java:511)
    04-06 19:50:30.326: E/ActivityThread(795):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
    04-06 19:50:30.326: E/ActivityThread(795):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
    04-06 19:50:30.326: E/ActivityThread(795):  at dalvik.system.NativeStart.main(Native Method)

很抱歉所有的错误，但我是Android应用程序的新手，我无法理解如何修复错误

Answer 1

注册并取消注册BroadcastReceiver试试这个：

<强> 1

//declare this as global in your class.
private LocationReceiver locationReceiver = new LocationReceiver();

然后在OnCreate()

中

IntentFilter filter = new IntentFilter("xxx.yyy.intent.action.LOCATION");    
this.registerReceiver(locationReceiver, filter);

然后在OnDestroy()取消注册locationReceiver，如下所示：

@Override
protected void onDestroy() {
    if (locationReceiver != null) {
        locationReceiver.cancel(true);
    }
    try {
        unregisterReceiver(locationReceiver);
    } catch (Exception e) {
        Log.e("UnRegister Receiver Error", "> " + e.getMessage());
    }
    super.onDestroy();
}

<强> 2 如果它没有用，那么删除你的LocationReceiver类并声明波纹管变量，这将与LocationReceiver相同：

private final BroadcastReceiver locationReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent calledIntent)
         Log.d("LOC_RECEIVER", "Location RECEIVED!");

         latitude = calledIntent.getDoubleExtra("latitude", -1);
         longitude = calledIntent.getDoubleExtra("longitude", -1);            
    }
};

然后在OnCreate()中，注册locationReceiver，如下所示：

IntentFilter filter = new IntentFilter("xxx.yyy.intent.action.LOCATION");    
this.registerReceiver(locationReceiver, filter);

然后在OnDestroy()取消注册locationReceiver，如下所示：

@Override
protected void onDestroy() {
    if (locationReceiver != null) {
        locationReceiver.cancel(true);
    }
    try {
        unregisterReceiver(locationReceiver);
    } catch (Exception e) {
        Log.e("UnRegister Receiver Error", "> " + e.getMessage());
    }
    super.onDestroy();
}

希望这会有所帮助。顺便说一句，我在我的项目中使用了第二种方法。