我收到一個nullPointerException錯誤,在其中一個方法期間,我似乎無法弄清楚爲什麼我的一個變量(csID)變爲空。NullPointerException異常Android Java
這裏是方法:
public String getSubjectBasedOnHID(int hID) {
String selectQuerySubjectForHomework = "SELECT sID FROM homework WHERE hID = '"
+ hID + "';";
HashMap<String, String> sIDD = new HashMap<String, String>();
SQLiteDatabase database = this.getReadableDatabase();
Cursor cursorGetsID = database.rawQuery(selectQuerySubjectForHomework,
null);
if (cursorGetsID.moveToFirst()) {
HashMap<String, String> temp = new HashMap<String, String>();
temp.put("sID", cursorGetsID.getString(0));
sIDD = temp;
}
String csID = sIDD.get("sID").toString();
String Subject = csID;
return Subject;
};
CSID成爲空(我認爲),這會導致程序崩潰,任何幫助將不勝感激!
的logcat:
01-07 18:58:45.854: E/AndroidRuntime(2630): Caused by: java.lang.NullPointerException
01-07 18:58:45.854: E/AndroidRuntime(2630): at com.compfour.homework.dataBaseTools2.getSubjectBasedOnHID(dataBaseTools2.java:284)
謝謝提前。
將是System.out.print一個在if語句,看它是否正在執行 – Ogen