我正在學習編碼,並製作了一個秒錶,它將字符串保存在字符串中,並將日期也作爲字符串來獲取。我想把它們放在一個SQLite數據庫中(這樣我以後可以在一個listview中顯示日期,並在另一個顯示所有laptimes的活動中打開它)。我已經在互聯網上跟蹤了一些代碼並嘗試將這些代碼放在一起所以我可能會查看我的代碼中的一些內容。我已經評論了我認爲我理解的部分,所以你可以按照我的想法做一點。Android Java SQLite數據庫:數據庫不需要2個字符串輸入
問題:當我按下保存下面的代碼執行並返回toastmessage:Somehting出錯了。
save.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
String dateStamp = getCurrentTimeStamp();
AddData(dataInput, dateStamp);
//DatabaseHelper.deleteAll();
}
}); //save data though AddData method as input the listText
的方法addData爲如下:
public void AddData(String time, String date) {
boolean insertData = DatabaseHelper.addData(time, date);
if (insertData) {
toastMessage(dataInput);
} else {
toastMessage("Something went wrong");
}
}
在DatabaseHelper類布爾方法是這樣的:
public boolean addData(String times, String date) { //addData that takes a string
SQLiteDatabase db = this.getWritableDatabase(); //database called db and use getWritableDatabase method
ContentValues contentValues = new ContentValues(); //make a new object of ContentValues
contentValues.put(COL_2, times); //put COL_2 and the String in the ContentValues object
contentValues.put(COL_3, date);
long result = db.insert(TABLE_NAME, null, contentValues); //insert contentValues object into the table
//if date as inserted incorrectly it will return -1
if (result == -1) {
db.close();
return false;
} else {
return true;
}
}
它的工作原理,當我在addData輸入只是1個變量()但是不是我以後實施的2。我認爲它應該工作。下面我還將用於製作SQLite數據庫的代碼放入其中。
public static final String TABLE_NAME = "stopwatch"; //make a table with name
public static final String COL_1 = "ID"; //make an ID for every colomn
public static final String COL_2 = "times"; //make a 2nd colomn for data
public static final String COL_3= "date";
public DatabaseHelper(Context context) {
super(context, TABLE_NAME, null, 1);
}
@Override
public void onCreate(SQLiteDatabase db) { //make the onCreate method that takes the database as input
String createTable = "CREATE TABLE " + TABLE_NAME + " (" + COL_1 + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
COL_2 +" TEXT" + COL_3 +" TEXT)"; //create the table with SQL statements to input the data correctly
db.execSQL(createTable); //input the SQL statements in the DB
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { //make upgrade method that takes the database and the versions
db.execSQL("DROP IF TABLE EXISTS " + TABLE_NAME); //execute SQL statements drop table and which one
onCreate(db); //run through create method
}
我希望有人能幫助我找到問題,以便我可以瞭解更多。
SQL語句是'DROP TABLE IF EXISTS .....''DROP IF TABLE EXISTS ....' – Titus
謝謝!我已經從另一個代碼中複製了這些內容,並試圖查看不同的內容,但作爲初學者,我仍然錯過了那些小東西 – Tmen