ParseQuery - 正確處理IndexOutOfBoundsException - Parse.com？

Question

如何正確處理throwIndexOutOfBoundsException？基本上，我正在查詢用戶。如果用戶存在，則顯示他們的個人資料。但是，如果找不到條目，​​它會崩潰我的應用程序並拋出異常。我應該在我的「其他」語句中放入什麼，以便應用程序不會崩潰？

    @Override 
        public void done(List<ParseUser> parseUsers, ParseException e) { 
          if (e == null) { 
            // The query was successful. 
            ParseUser user = parseUsers.get(0); 
            String userId = user.getObjectId(); 
            showProfileActivity(userId); 

          } else { 
           // The query was unsuccessful. 

          } 
         } 
        }); 

這裏是logcat的：

10-14 21:27:06.888 28595-28595/com.app.social E/AndroidRuntime﹕ FATAL EXCEPTION: main 
    Process: com.elgami.customizer, PID: 28595 
    java.lang.IndexOutOfBoundsException: Invalid index 0, size is 0 
      at java.util.ArrayList.throwIndexOutOfBoundsException(ArrayList.java:255) 
      at java.util.ArrayList.get(ArrayList.java:308) 
      at com.elgami.feed.SearchActivity$1$1.done(SearchActivity.java:74) 
      at com.elgami.feed.SearchActivity$1$1.done(SearchActivity.java:67) 
      at com.parse.Parse$6$1.run(Parse.java:944) 
      at android.os.Handler.handleCallback(Handler.java:739) 
      at android.os.Handler.dispatchMessage(Handler.java:95) 
      at android.os.Looper.loop(Looper.java:148) 
      at android.app.ActivityThread.main(ActivityThread.java:5417) 
      at java.lang.reflect.Method.invoke(Native Method) 
      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 

Answer 1

你可以檢查列表爲空：

@Override 
     public void done(List<ParseUser> parseUsers, ParseException e) { 
           if (!parseUsers.isEmpty()) { 
             // The query was successful. 
             ParseUser user = parseUsers.get(0); 
             String userId = user.getObjectId(); 
             showProfileActivity(userId); 

           } else { 
            // The query was unsuccessful. 

           } 
          } 
         }); 

，或者如果你想趕上異常使用嘗試-catch是這樣的：

@Override 
    public void done(List<ParseUser> parseUsers, ParseException e) { 
      if (e==null) { 
      // The query was successful. 
      try{ 
       ParseUser user = parseUsers.get(0); 
       String userId = user.getObjectId(); 
      } 
     catch(ArrayIndexOutOfBoundsException e) 
      { 
     // Print message for user does not exist . 
      } 
      showProfileActivity(userId); 
      } 
       else { 
        // The query was unsuccessful. 
        } 
         } 
          });