将数据存储到 sqlite

Question

MainData helper = new MainData(this);name
    SQLiteDatabase db = helper.getWritableDatabase();        

String uid = MessageRecieverId;
    int userData = 0;
    Cursor data2 = helper.getUserData();
    while (data2.moveToNext()) {
        userData = data2.getInt(data2.getColumnIndex(KEY_MESSAGES_SENT));
    }
    ContentValues contentValues2 = new ContentValues();
    contentValues2.put(KEY_ID, uid);
    contentValues2.put(KEY_MESSAGES_SENT, userData+1);
    long returnVariable2 = db.update(TABLE_USER_DATA, contentValues2,null,null);
    if (returnVariable2 == -1) {
        Toast.makeText(getApplication(), "Nope", Toast.LENGTH_LONG).show();
        //-1 means there was an error updating the values
    } else {
        Toast.makeText(getApplication(),"uf", Toast.LENGTH_SHORT).show();
    }
}

userData+1 应该只对 KEY_ID = uid 的行执行，但它会将所有行的值更改为 +1 而不仅仅是... MessageRecieverId 不同，但数据将其更改为所有行...任何人都可以帮忙我解决这个问题？

帮手

    String userQuery = "CREATE TABLE IF NOT EXISTS " + TABLE_USER_DATA + "(" + KEY_ID + " TEXT, " + KEY_NAME
            + " TEXT, " + KEY_MESSAGES_SENT + " INTEGER, " + KEY_MESSAGES_RECIEVED + " INTEGER, "
            + KEY_MESSAGES + " INTEGER, " + KEY_TIME_SPENT + " TEXT)";

方法

    public Cursor getUserData() {
    SQLiteDatabase db = this.getWritableDatabase();
    String query = "SELECT * FROM " + TABLE_USER_DATA;
    return db.rawQuery(query, null);
}

我在查看答案后添加了 where 子句并收到一条错误消息，指出不存在此类列

添加默认数据

public void Start(){
    MainData helper = new MainData(this); //Change the name to your Helper Class name
    SQLiteDatabase db = helper.getWritableDatabase();
    ContentValues contentValues = new ContentValues();
    contentValues.put(KEY_ID, MessageRecieverId);
    contentValues.put(KEY_NAME, MessageRecieverName);
    contentValues.put(KEY_MESSAGES_SENT, 0);
    contentValues.put(KEY_MESSAGES_RECIEVED, 0);
    contentValues.put(KEY_MESSAGES, 0);
    contentValues.put(KEY_TIME_SPENT, "");

    long returnVariable = db.insert(TABLE_USER_DATA,null,contentValues);
    if (returnVariable == -1) {
        Toast.makeText(getApplication(), "Nope", Toast.LENGTH_LONG).show();
        //-1 means there was an error updating the values
    } else {
        Toast.makeText(getApplication(),"Done", Toast.LENGTH_SHORT).show();
        SharedPreferences sp = getSharedPreferences(MessageRecieverId, Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = sp.edit();
        editor.putBoolean("Data", true); //save that the user enters username
        editor.apply();
    }

}

像这样添加数据后，我将其增加一，但显示错误

 Process: com.appmaster.akash.messageplus, PID: 24433
                                                                             android.database.sqlite.SQLiteException: no such column: eR3C1LXJhzaK3fPzCpcuTuz9jZB3 (code 1): , while compiling: UPDATE UserData SET MessagesSent=? WHERE RecieversID =eR3C1LXJhzaK3fPzCpcuTuz9jZB3
                                                                                 at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
                                                                                 at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:889)
                                                                                 at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:500)
                                                                                 at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588)
                                                                                 at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:58)
                                                                                 at android.database.sqlite.SQLiteStatement.<init>(SQLiteStatement.java:31)
                                                                                 at android.database.sqlite.SQLiteDatabase.updateWithOnConflict(SQLiteDatabase.java:1577)
                                                                                 at android.database.sqlite.SQLiteDatabase.update(SQLiteDatabase.java:1525)
                                                                                 at com.appmaster.akash.messageplus.Chat.mMessagesSent(Chat.java:913)
                                                                                 at com.appmaster.akash.messageplus.Chat.sendMessage(Chat.java:704)
                                                                                 at com.appmaster.akash.messageplus.Chat.access$900(Chat.java:75)
                                                                                 at com.appmaster.akash.messageplus.Chat$5.onClick(Chat.java:441)
                                                                                 at android.view.View.performClick(View.java:6256)
                                                                                 at android.view.View$PerformClick.run(View.java:24701)
                                                                                 at android.os.Handler.handleCallback(Handler.java:789)
                                                                                 at android.os.Handler.dispatchMessage(Handler.java:98)
                                                                                 at android.os.Looper.loop(Looper.java:164)
                                                                                 at android.app.ActivityThread.main(ActivityThread.java:6541)
                                                                                 at java.lang.reflect.Method.invoke(Native Method)
                                                                                 at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
                                                                                 at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)

Answer 1

您正在将db.update 调用中的where 子句和where args 参数专门设置为null。这就是该命令更新所有行的原因，因为没有 where 子句。

您需要更改此行中的最后两个参数：

long returnVariable2 = db.update(TABLE_USER_DATA, contentValues2,null,null);

以下是官方文档中的详细信息：

https://developer.android.com/reference/android/database/sqlite/SQLiteDatabase.html#update(java.lang.String,%20android.content.ContentValues,%20java.lang.String,%20java.lang.String[])

Answer 2

UPDATE 将更新每一行，除非您指定要更新的行。

因此long returnVariable2 = db.update(TABLE_USER_DATA, contentValues2,null,null);，

因为选择（第三个参数）是 null 将更新每一行。

选择是一个 WHERE 子句（减去 WHERE 关键字）；第 4 个参数可用于将参数传递到 WHERE 子句中，逐一替换 ?。

• 以这种方式传递参数的优点是它们将被正确封装/处理，并且
• 提供针对 SQL 注入的保护。

例如您很可能想要以下内容：-

//contentValues2.put(KEY_ID, uid); //<<<<<<<<<< YOU PROBABLY DO NOT WANT TO CHANGE THE ID, so commented out
contentValues2.put(KEY_MESSAGES_SENT, userData+1);
String whereclause = KEY_ID + "=?";
String[] whereargs = new String[]{uid};
long returnVariable2 = db.update(TABLE_USER_DATA, contentValues2,whereclause,whereargs);

请注意，更新返回的 int 不是很长，而且它永远不会是 -1，因为它是已更新的行数，因此为 0 或更大。所以你需要为 Toast 检查 0 而不是 -1

Answer 3

    ContentValues cv = new ContentValues();
    cv.put("isSynced", 1);
    db.update(TABLE_NAME, cv, "id =" + recID, null);

使用 where 条件更新代码。希望能成功