Question

在我的应用程序中，我想设置标记为收藏夹quote.On按钮单击我想为该特定行设置该标志。在我的数据库中，对于引号我采取了TEXT数据格式和boo lean BOOL.I已经管理从数据库中检索文本值但是我无法在数据库中设置布尔值。由于我是这个主题的新手，所以对此有任何帮助都非常感谢。以下是我的代码

public class DatabaseHelper extends SQLiteOpenHelper{
    //The Android's default system path of your application database.
    private static String DB_PATH = "/data/data/com.t4t.smspopup/databases/";
    private static String DB_NAME = "smspopupplus.sqlite";
    private static SQLiteDatabase myDataBase; 
    private final Context myContext;
    public static String Column_Favorite="0"; 

    public DatabaseHelper(Context context) {
        super(context, DB_NAME, null, 1);
        this.myContext = context;
    }

    public void createDataBase() throws IOException
    {
        boolean dbExist = checkDataBase();      
        SQLiteDatabase db_Read = null;
        if(dbExist)
        {

        }
        else
        {
            db_Read=this.getReadableDatabase();
            db_Read.close();
            Log.i("debug++++", "databse created");
            try
            {
                copyDataBase();
            }
            catch (IOException e)
            {
                e.printStackTrace();
                throw new Error("Error copying database");
            }
        }
    }

    public boolean checkDataBase()
    {
        SQLiteDatabase checkDB = null;

        try
        {
            String myPath = DB_PATH + DB_NAME;
            checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
        }
        catch(SQLiteException e)
        {

        }

        if(checkDB != null)
        {
            checkDB.close();
        }

        return checkDB != null ? true : false;
    }

    public void copyDataBase() throws IOException
    {
        InputStream myInput = myContext.getAssets().open(DB_NAME);
        String outFileName = DB_PATH + DB_NAME;
        OutputStream myOutput = new FileOutputStream(outFileName);
        byte[] buffer = new byte[1024];
        int length;
        while ((length = myInput.read(buffer))>0)
        {
            myOutput.write(buffer, 0, length);
        }

        myOutput.flush();
        myOutput.close();
        myInput.close();
    }

    public void openDataBase() throws SQLException
    {
        String myPath = DB_PATH + DB_NAME;
        myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READWRITE);
        Log.i("debug++++", "databse opened");
    }

    public void close()
    {
        if(myDataBase != null)
            myDataBase.close();

        super.close();
    }

    @Override
    public void onCreate(SQLiteDatabase db)
    {

    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
    {

    }

    public boolean updateDB(String status,String what,int value)
    {
        return false;

    }
    //retrive sms text from DB
    public  ArrayList<String> getSMSList(String categoryName)
    {
        ArrayList<String> SMSList = new ArrayList<String>();

        try{
            Cursor cursor=null;


            cursor = myDataBase.query(true,categoryName,null,null,null,null,null,null,null);
            while(cursor.moveToNext())
            {
                //ProgressData progress = new ProgressData(cursor.getString(0),cursor.getString(1));
                String SMSString=cursor.getString(1);
                SMSList.add(SMSString);
                //Log.i("debug++++", ""+progressList);
            }
            cursor.close();

        }catch (Exception e) {
            e.printStackTrace();
        }

        return SMSList;
    }


    @SuppressWarnings("null")
    public void execSql(String sql,Object[] args)
    {
        SQLiteDatabase sqLiteDatabase = null;
        if(args==null)
        {
            sqLiteDatabase.execSQL(sql);
        }
        else

        {
            Log.e("debug -----------", "command execuated");
            sqLiteDatabase.execSQL(sql,args);
        }

    }

Answer 1

SQLite Boolean Datatype:
SQLite没有单独的布尔存储类。相反，布尔值存储为整数0（假）和1（真）。

你可以用这种方式将boolean转换为int：

int flag = (boolValue==true)? 1:0;
String query = "UPDATE "+ TABLE_NAME + " set "+COLUMN_NAME+" = "+flag + " where "+CONDITION;
myDataBase.exeSQL(query);

您可以将int转换回布尔值，如下所示：

 // Select COLUMN_NAME 'flag' values from db. 
 // This will be integer value, you can convert this int value back to Boolean as follows
Boolean flag2 = (intValue==1)?true:false;

Answer 2

要更改表中的值，您需要UPDATE语句。您可以查看http://www.sqlite.org/lang_update.html中的语法。

Answer 3

如果要将布尔数据存储在SQLite数据库中，可以将布尔值存储为整数0（false）和1（true）

Answer 4

我总是使用TINYINT在我的数据库中保存标志，因为它需要
DB中的空间最少。后来我只是转换状态
用if-shorthand：

post.postFaved = post.postFaved == 1 ? 0 : 1;

在android中的sqlite数据库中设置标志

4 个答案: