java.lang.NullPointerException:println需要一个消息

我得到errror:java.lang.NullPointerException:println使用这种方法时需要一个消息:

lst_info = new HashMap<String, String>(); SystemDatabaseHandler db = new SystemDatabaseHandler(getApplicationContext()); lst_info = db.getLstInfo(sql_id); 

SystemDatabaseHandler:

 public HashMap<String , String> getLstInfo(int id){ HashMap<String , String> lst_temp; lst_temp = new HashMap<String , String>(); String selectQuery = "SELECT * FROM dkr_lst_lst WHERE lst_id = " + id; SQLiteDatabase db = this.getWritableDatabase(); Cursor cursor = db.rawQuery(selectQuery, null); if (cursor.moveToFirst()) { do { Log.d("sql_id", cursor.getString(0)); lst_temp.put("sql_id", cursor.getString(0)); }while (cursor.moveToNext()); } cursor.close(); db.close(); return lst_temp; } 

Log.d(“sql_id”,cursor.getString(0)); 回报我:

07-12 11:56:05.603:D / sql_id(13783):1

日志猫:

 07-12 11:56:05.613: D/Database(13783): dbclose(): path = /data/data/de.bodprod.dkr/databases/dkr, handle = 0x4301a8 07-12 11:56:05.613: D/AndroidRuntime(13783): Shutting down VM 07-12 11:56:05.613: W/dalvikvm(13783): threadid=1: thread exiting with uncaught exception (group=0x4001d5a0) 07-12 11:56:05.623: E/AndroidRuntime(13783): FATAL EXCEPTION: main 07-12 11:56:05.623: E/AndroidRuntime(13783): java.lang.RuntimeException: Unable to start activity ComponentInfo{de.bodprod.dkr/de.bodprod.dkr.BosLstDetailMap}: java.lang.NullPointerException: println needs a message 07-12 11:56:05.623: E/AndroidRuntime(13783): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1872) 07-12 11:56:05.623: E/AndroidRuntime(13783): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1893) 07-12 11:56:05.623: E/AndroidRuntime(13783): at android.app.ActivityThread.access$1500(ActivityThread.java:135) 07-12 11:56:05.623: E/AndroidRuntime(13783): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1054) 07-12 11:56:05.623: E/AndroidRuntime(13783): at android.os.Handler.dispatchMessage(Handler.java:99) 07-12 11:56:05.623: E/AndroidRuntime(13783): at android.os.Looper.loop(Looper.java:150) 07-12 11:56:05.623: E/AndroidRuntime(13783): at android.app.ActivityThread.main(ActivityThread.java:4385) 07-12 11:56:05.623: E/AndroidRuntime(13783): at java.lang.reflect.Method.invokeNative(Native Method) 07-12 11:56:05.623: E/AndroidRuntime(13783): at java.lang.reflect.Method.invoke(Method.java:507) 07-12 11:56:05.623: E/AndroidRuntime(13783): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:849) 07-12 11:56:05.623: E/AndroidRuntime(13783): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:607) 07-12 11:56:05.623: E/AndroidRuntime(13783): at dalvik.system.NativeStart.main(Native Method) 07-12 11:56:05.623: E/AndroidRuntime(13783): Caused by: java.lang.NullPointerException: println needs a message 07-12 11:56:05.623: E/AndroidRuntime(13783): at android.util.Log.println_native(Native Method) 07-12 11:56:05.623: E/AndroidRuntime(13783): at android.util.Log.d(Log.java:137) 07-12 11:56:05.623: E/AndroidRuntime(13783): at de.bodprod.dkr.BosLstDetailMap.onCreate(BosLstDetailMap.java:43) 07-12 11:56:05.623: E/AndroidRuntime(13783): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1072) 07-12 11:56:05.623: E/AndroidRuntime(13783): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1836) 07-12 11:56:05.623: E/AndroidRuntime(13783): ... 11 more 07-12 11:56:07.495: D/Process(13783): killProcess, pid=13783 

Solutions Collecting From Web of "java.lang.NullPointerException:println需要一个消息"

也许当你这样做

 Log.d("sql_id", cursor.getString(0)); 

cursor.getString(0)返回null,然后崩溃。

试着做 :

 if(cursor.getString(0) != null) { Log.d("sql_id", cursor.getString(0)); } 

否则告诉我们de.bodprod.dkr.BosLstDetailMap.onCreate(BosLstDetailMap.java:43)

试试:

 Log.d("sql_id"," " + cursor.getString(0)); 

代替

 Log.d("sql_id", cursor.getString(0)); 

也许你正在Log.d中传递第二个参数empty或null