MainActivty中的意圖回收

Question

我試圖從EditText字段接收到一個條目後，在我的MainActivity類中啓動一個意圖。我通過額外的數據傳遞一些數據。在我的MainActivity中，我檢查是否有任何來自Intent的額外內容。如果是的話，我在一個異步任務中處理數據。問題是我的MainActivity經歷了兩次檢查從一個意圖和最終程序炸彈的額外過程。這非常令人困惑，我會在下面展示程序如何流動。首先在MainActivity下的另一個活動中啓動意圖。

thisLocation = (EditText) findViewById(R.id.restlocation); 

     thisLocation.setOnKeyListener(new View.OnKeyListener() { 
      public boolean onKey(View v, int keyCode, KeyEvent event) { 
       if((keyCode == KeyEvent.KEYCODE_DPAD_CENTER) || 
         (keyCode == KeyEvent.KEYCODE_ENTER)) { 
        String location = thisLocation.getText().toString(); 
        Log.d("Location in key listener", location); 
        try 
        { 
        List<Address> foundGeocode = null; 

        foundGeocode = new Geocoder(getApplicationContext()).getFromLocationName(location, 1); 
        double newlat = foundGeocode.get(0).getLatitude(); //getting latitude 
        double newlng = foundGeocode.get(0).getLongitude();//getting longitude 
        Log.d("Lat in key listener", String.valueOf(newlat)); 
        Intent intent = new Intent(getApplicationContext(), MainActivity.class); 
        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP); 
        intent.putExtra("lat", String.valueOf(lat)); 
        intent.putExtra("lng", String.valueOf(lng)); 
        startActivity(intent); 

        } 

        catch (IOException e) { 
         Log.e("Geocode", String.valueOf(e)); 
        } 

    return true; 
    } 
    return false; 
    } 
}); 

我可以從我的日誌，告訴大家，處理經過上述程序要在MainActivity之前的兩倍。在第一次通過監聽器之後，logcat顯示標籤'MapActivity'和上面活動的「onDestroy爲com.example.herbx.Restaurant打開燈光」的文本。下一次通過我輸入我的MainActivity，它也通過下面的邏輯兩次，每次前面有我的logcat上的以下消息：Tag = MapActivity Text =回收地圖對象。

下面的內容是從上述活動收到的來自Intent的附加內容的MainActivity處理。

protected void onCreate(Bubdke savedInstanceState) { 
     ...... intialization code 

     Bundle extras = getIntent().getExtras(); 
    if(extras != null) 
    { 

     lat = Float.parseFloat(extras.getString("lat")); 
     lng = Float.parseFloat(extras.getString("lng")); 
     Log.d("lat=", String.valueOf(lat)); 
     NewMap(lat, lng); // This is an asynchronous task 
    } 
     } 

下面是我的logcat的轉儲，顯示我在哪裏記錄了某些數據。

03-20 19:21:30.256: D/Location in key listener(4045): Peoria 
    03-20 19:21:30.519: D/Lat in key listener(4045): 40.6936488 
    03-20 19:21:30.616: D/MapActivity(4045): onDestroy leaving the lights on for com.example.herb4.Restaurant@40fc2f88 
    03-20 19:21:30.736: D/Location in key listener(4045): Peoria 
    03-20 19:21:30.986: D/Lat in key listener(4045): 40.6936488 
    03-20 19:21:31.016: I/Choreographer(4045): Skipped 45 frames! The application may be doing too much work on its main thread. 
    03-20 19:21:31.168: W/MapActivity(4045): Recycling dispatcher android_maps_conflict_avoidance.com.google.googlenav.datarequest.DataRequestDispatcher@40cf8f38 
    03-20 19:21:31.207: V/MapActivity(4045): Recycling map object. 
    03-20 19:21:31.426: D/lat=(4045): 40.9040412902832 
    03-20 19:21:31.746: D/newmap addr=(4045): W 7th StMinonk, IL 61760 
    03-20 19:21:31.896: W/MapActivity(4045): Recycling dispatcher android_maps_conflict_avoidance.com.google.googlenav.datarequest.DataRequestDispatcher@40cf8f38 
    03-20 19:21:31.948: V/MapActivity(4045): Recycling map object. 
    03-20 19:21:32.166: D/lat=(4045): 40.9040412902832 
    03-20 19:21:32.206: D/GetRestaurant lat=(4045): 40.9040412902832 
    03-20 19:21:32.387: D/newmap addr=(4045): W 7th StMinonk, IL 61760 
    03-20 19:21:32.446: I/Choreographer(4045): Skipped 69 frames! The application may be doing too much work on its main thread. 
    03-20 19:21:32.726: D/dalvikvm(4045): GREF has increased to 201 
    03-20 19:21:32.956: D/InputEventConsistencyVerifier(4045): KeyEvent: ACTION_UP but key was not down. 
    03-20 19:21:32.956: D/InputEventConsistencyVerifier(4045): in android.view.ViewRootImpl@4109f880 
    03-20 19:21:32.956: D/InputEventConsistencyVerifier(4045): 0: sent at 15675516000000, KeyEvent { action=ACTION_UP, keyCode=KEYCODE_ENTER, scanCode=28, metaState=0, flags=0x8, repeatCount=0, eventTime=15675516, downTime=15675423, deviceId=0, source=0x101 } 
    03-20 19:21:33.166: E/InputEventReceiver(4045): Exception dispatching input event. 
    03-20 19:21:33.166: E/MessageQueue-JNI(4045): Exception in MessageQueue callback: handleReceiveCallback 
    03-20 19:21:33.256: E/MessageQueue-JNI(4045): java.lang.IndexOutOfBoundsException: Invalid index 0, size is 0 
    03-20 19:21:33.256: E/MessageQueue-JNI(4045): at java.util.ArrayList.throwIndexOutOfBoundsException(ArrayList.java:251) 
    03-20 19:21:33.256: E/MessageQueue-JNI(4045): at java.util.ArrayList.get(ArrayList.java:304) 

所以我的問題是，當我在上面的第一個活動中輸入數據時，程序爲什麼會經歷兩次邏輯？這是非常混亂和最終的結果，我得到一個erorr在MessageQueue callbackL handleReceiveCallback和IndexOutOfBoundsException異常說。
如果有人需要關於這個令人困惑的問題的更多信息，請讓我知道。

下面是它出現的代碼我得到了nullexception，但我得到了「GetRestaurant lat =」的第一個日誌，但我沒有得到第二個日誌是「GetRestaurant try」。我不知道這兩個日誌之間會發生什麼樣的扭曲。另外，我從其他來源進入這個例程並且工作，在這種情況下不起作用。

List<String> result = new ArrayList<String>(); 
URL url; 
Log.d("GetRestaurant lat=", thislat); // this gets logged 
try { 
Log.d("GetRestaurant try", ""); // this doesn't get logged 
String query = "?lat=" + thislat + "&lng=" + thislng + "&uid=&vegkey=1"; 
url = new URL("http://10.0.2.2:8000/herbivorenew/webservice/frontpage1.php" + query); 
HttpURLConnection httpConnection = (HttpURLConnection) url.openConnection(); 
int responseCode = httpConnection.getResponseCode(); 
if(responseCode == HttpURLConnection.HTTP_OK) { 
    InputStream in = httpConnection.getInputStream(); 
    BufferedReader br = new BufferedReader(
     new InputStreamReader(in)); 
String line; 

int x=0; 
while ((line = br.readLine()) != null) { 
    result = new ArrayList<String>(Arrays.asList(line.split("&"))); 
    Log.d("GetRestaurant result=", String.valueOf(result.get(0))); 
    x++; 
} 

Answer 1

onKey（）被調用兩次，一次當鍵被按下，一次當鍵被釋放時。你需要做的是這樣的：

public boolean onKey(View v, int keyCode, KeyEvent event) { 

     if (keyCode == KeyEvent.KEYCODE_DPAD_CENTER || 
      keyCode == KeyEvent.KEYCODE_ENTER) { 
      if (event.getAction()!=KeyEvent.ACTION_DOWN) { 
       return true; 
      } 

      // here goes your code 

      return true; 
     } 

     return false; 
    }