SQLiteDatabase db = this.getReadableDatabase();
Cursor mCursor =db.query(TABLE_ACCOUNTS, new String[]{a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s}, null,null, null, null, null);
我的問題是: 將這個初始化允許在DB數據庫&表返回所有值?使用參數
據我的項目,它似乎只是返回NULL值。 (無錯誤) a = null,b = null,c = null
當我用+「=?」操作第三個參數時檢測到一些實際值。和變化(現在爲空)。
或者可以預防實際值是別的嗎? (假設將數據添加到DB作品)
(添加代碼)
public void addAccount() {
SQLiteDatabase db = this.getWritableDatabase();
Account account = new Account();
ContentValues values = new ContentValues();
values.put(id, account.getA()); // Contact Name
values.put(a, account.getA()); // Contact Phone Number
values.put(b, account.getB()); // Contact Phone Number
values.put(c, account.getC());
...
db.insert(TABLE_ACCOUNTS, null, values);
db.close(); // Closing database connection
}
(光標代碼)
if ((mCursor != null && mCursor.moveToFirst())) {
do {
stringResult1 =
"a: "+ mCursor.getString(0)+ "\n"
+ "b: " + mCursor.getString(1) + "\n"
+ "c: " + mCursor.getString(2) + "\n"
+ "d: " + mCursor.getString(3) + "\n"
+ "e: " + mCursor.getString(4) + "\n"
+ "f: " + mCursor.getString(5) + "\n"
+ "g: " + mCursor.getString(6) + "\n"
+ "h: " + mCursor.getString(7) + "\n"
+ "i " + mCursor.getString(8) + "\n"
+ "j: " + mCursor.getString(9) + "\n"
+ "k: " + mCursor.getString(10) + "\n"
+ "l: " + mCursor.getString(11) + "\n"
+ "m: " + mCursor.getString(12) + "\n"
+ "n: " + mCursor.getString(13) + "\n"
+ "o: " + mCursor.getString(14) + "\n"
+ "p: " + mCursor.getString(15) + "\n"
+ "q: " + mCursor.getString(16) + "\n"
+ "r: " + mCursor.getString(17) + "\n"
+ "s: " + mCursor.getString(18) + "\n";
} while (mCursor.moveToNext());
// make sure to close the cursor
mCursor.close();
}
什麼是a,b,c,d ....?他們是字符串變量 – TNR
是 字符串CREATE_CONTACTS_TABLE =「CREATE TABLE」+ TABLE_ACCOUNTS +「(」 + a +「TEXT PRIMARY KEY」,+ b +「TEXT」, + c +「TEXT」+ d +「TEXT, 「+ e +」文本,「+ f +」文本,「+ g +」文本「+ h +」文本「+ i +」文本「+ j +」文本「+ k +」文本「 「+ m +」TEXT,「+ n +」TEXT「,+ o +」TEXT「,+ p +」TEXT「+ q +」TEXT「+ r +」TEXT「 db.execSQL(CREATE_CONTACTS_TABLE); – babyhir
你還可以添加變量聲明代碼嗎? – TNR