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在我的代碼中,我正在動態地形成一個字符串數組。 然後,當我嘗試通過「length」屬性獲取數組的大小時,應用程序崩潰,發出空指針異常。 有沒有另一種獲得數組長度的方法?字符串數組長度給出空指針android
File Cur_folder=new File(""+folder.toString());
String[] dirList=Cur_folder.list();
int c=dirList.length;
登錄貓:
07-23 03:02:40.477: E/AndroidRuntime(1576): FATAL EXCEPTION: AsyncTask #1
07-23 03:02:40.477: E/AndroidRuntime(1576): Process: com.example.nusearch, PID: 1576
07-23 03:02:40.477: E/AndroidRuntime(1576): java.lang.RuntimeException: An error occured while executing doInBackground()
07-23 03:02:40.477: E/AndroidRuntime(1576): at android.os.AsyncTask$3.done(AsyncTask.java:300)
07-23 03:02:40.477: E/AndroidRuntime(1576): at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
07-23 03:02:40.477: E/AndroidRuntime(1576): at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
07-23 03:02:40.477: E/AndroidRuntime(1576): at java.util.concurrent.FutureTask.run(FutureTask.java:242)
07-23 03:02:40.477: E/AndroidRuntime(1576): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
07-23 03:02:40.477: E/AndroidRuntime(1576): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
07-23 03:02:40.477: E/AndroidRuntime(1576): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
07-23 03:02:40.477: E/AndroidRuntime(1576): at java.lang.Thread.run(Thread.java:841)
07-23 03:02:40.477: E/AndroidRuntime(1576): Caused by: java.lang.NullPointerException
07-23 03:02:40.477: E/AndroidRuntime(1576): at com.example.nusearch.MainActivity$StartIndexing.doInBackground(MainActivity.java:97)
07-23 03:02:40.477: E/AndroidRuntime(1576): at com.example.nusearch.MainActivity$StartIndexing.doInBackground(MainActivity.java:1)
07-23 03:02:40.477: E/AndroidRuntime(1576): at android.os.AsyncTask$2.call(AsyncTask.java:288)
07-23 03:02:40.477: E/AndroidRuntime(1576): at java.util.concurrent.FutureTask.run(FutureTask.java:237)
07-23 03:02:40.477: E/AndroidRuntime(1576): ... 4 more
安置自己的代碼,然後.... –
OK等待sec..i'll張貼 – user2820823
似乎陣列本身是'null'。 – Henry