Java.util.List.toArray () experience in using

Java.util.List.toArray () experience in usingTags: objectstringexceptionlistnull 2012-02-28 11:23 18713 people read Comments (0) Favorites Report Category: Android_ character processing (2)

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After the following code executes:

[Java]  View plain  copy Private void onbuttonlisttoarrayclick ()  {        // array--->List       string[] strarray = new  String[] {  "AA",  "BB"  };       List<String>  List = new arraylist<string> (Arrays.aslist (strarray));        list.add ("CC");       // list--->Array        String[] strArray2;       try {            strArray2 =  (string[])  list.toarray ();        } catch  (exception e)  {          &NBSP;&NBSP;LOG.I ("ToArray",  "Failure:"  + e.getmessage ());       }      }  
Exception occurred

Because List.toarray () returns the object type, it occurs when the cast is classcastexception

The procedure is amended as follows:

[Java]  View plain  copy Private void onbuttonlisttoarrayclick ()  {        // array--->List       string[] strarray = new  String[] {  "AA",  "BB"  };       List<String>  List = new arraylist<string> (Arrays.aslist (strarray));        list.add ("CC");       // list--->Array        String[] strArray2 = null;       try {            strarray2 = list.toarray (new String[0]);        } catch  (exception e)  {       &NBSP;&NBSP;&NBSP;&NBSP;&NBSP;LOG.I ("ToArray",  "Failure:"  + e.getmessage ());        }       for  (string element : strarray2)  {   &NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;LOG.I ("ToArray",  "StrArray2:"  + element);        }     }  
Run Result:

The method above

[Java] view plain Copy strArray2 = List.toarray (new string[0));
As with the following method

[Java] view plain copy strArray2 = new String[list.size ()];