1. Wir haben diesmal 2 Gewinnspiele zeitgleich für euch - Gewinne einmal ein UMI Plus E - Beim 2ten könnt ihr ein Nomu S30 gewinnen!
  1. 19sheriff93, 09.06.2012 #1
    19sheriff93

    19sheriff93 Threadstarter Junior Mitglied

    Hi leute!
    Ich habe eine vorgefertigte Datenbank, diese vom Assetts ordner zu kopieren ist kein problem, nur habe ich folgendes problem: Welche public methods brauche ich um eine abrfrage zu erstellen (DB soll nur daten liefern, keine speichern bzw verändern) Hier wäre der code den ich jetzt habe:

    Code:
    package at.android.twhk;
    
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.io.InputStream;
    import java.io.OutputStream;
    import java.sql.SQLException;
    import android.content.Context;
    import android.database.Cursor;
    import android.database.sqlite.SQLiteDatabase;
    import android.database.sqlite.SQLiteException;
    import android.database.sqlite.SQLiteOpenHelper;
    
    
    public class DataBaseHelper extends SQLiteOpenHelper{
     
        //The Android's default system path of your application database.
        private static String DB_PATH = "/data/data/at.android.twhk/databases/";
        private static String DB_NAME = "twhk_android_sqlite";
    
     
        private SQLiteDatabase myDataBase; 
     
        private final Context myContext;
         
        /**
         * Constructor
         * Takes and keeps a reference of the passed context in order to access to the application assets and resources.
         * @param context
         */
        public DataBaseHelper(Context context) {
     
            super(context, DB_NAME, null, 1);
            this.myContext = context;
        }    
     
      /**
         * Creates a empty database on the system and rewrites it with your own database.
         * */
        public void createDataBase() throws IOException{
     
            boolean dbExist = checkDataBase();
     
            if(dbExist){
                //do nothing - database already exist
            }else{
     
                //By calling this method and empty database will be created into the default system path
                   //of your application so we are gonna be able to overwrite that database with our database.
                this.getReadableDatabase();
     
                try {
     
                    copyDataBase();
     
                } catch (IOException e) {
     
                    throw new Error("Error copying database");
     
                }
            }
     
        }
     
        /**
         * Check if the database already exist to avoid re-copying the file each time you open the application.
         * @return true if it exists, false if it doesn't
         */
        private boolean checkDataBase(){
     
            SQLiteDatabase checkDB = null;
     
            try{
                String myPath = DB_PATH + DB_NAME;
                checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
     
            }catch(SQLiteException e){
     
                //database does't exist yet.
     
            }
     
            if(checkDB != null){
     
                checkDB.close();
     
            }
     
            return checkDB != null ? true : false;
        }
     
        /**
         * Copies your database from your local assets-folder to the just created empty database in the
         * system folder, from where it can be accessed and handled.
         * This is done by transfering bytestream.
         * */
        private void copyDataBase() throws IOException{
     
            //Open your local db as the input stream
            InputStream myInput = myContext.getAssets().open(DB_NAME);
     
            // Path to the just created empty db
            String outFileName = DB_PATH + DB_NAME;
     
            //Open the empty db as the output stream
            OutputStream myOutput = new FileOutputStream(outFileName);
     
            //transfer bytes from the inputfile to the outputfile
            byte[] buffer = new byte[1024];
            int length;
            while ((length = myInput.read(buffer))>0){
                myOutput.write(buffer, 0, length);
            }
     
            //Close the streams
            myOutput.flush();
            myOutput.close();
            myInput.close();
     
        }
     
        public void openDataBase() throws SQLException{
     
            //Open the database
            String myPath = DB_PATH + DB_NAME;
            myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
     
        }
     
        @Override
        public synchronized void close() {
     
                if(myDataBase != null)
                    myDataBase.close();
     
                super.close();
     
        }
        
        
        
        
    [COLOR=Red]    // Add your public helper methods to access and get content from the database.
       // You could return cursors by doing "return myDataBase.query(....)" so it'd be easy
       // to you to create adapters for your views.[/COLOR]
        
        
    
        @Override
        public void onCreate(SQLiteDatabase db) {
            // TODO Auto-generated method stub
            
        }
    
        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
            // TODO Auto-generated method stub
            
        }
    
        public void open() {
            // TODO Auto-generated method stub
            
        }
    
        
    
        
            
            
    
        
    
    }
    Sind die methoden bis jetzt richtig? Bzw was benötige ich noch?

    lg und danke im vorraus :smile:
     
  2. Madlip, 12.06.2012 #2
    Madlip

    Madlip Fortgeschrittenes Mitglied

    Ich mach die Abfrage in meiner Activity wo ich es brauche, das kann dann wie folgt aussehen:

    Code:
    private StorageDBOpenHelper dbHelper;
    
    public oncreate(){
    dbHelper = new StorageDBOpenHelper(this);
    }
    
    public void getDataFromDB(){
    String statement = "select * from listen_with_info";
    SQLiteDatabase db = dbHelper.getWritableDatabase();
    
    Cursor cursor = db.rawQuery(statement, new String[] {});
                    
                    String listResult = "";
                    while (cursor.moveToNext())
                    {
                        for (int i = 0; i < cursor.getColumnCount(); i++)
                        {
                            if (i > 0)
                            {
                                
                                listResult += cursor.getString(i);
                              
                            }
                        }
                        
                        stringsForList.add(listResult);
                        listResult = "";
                       
                    }
    }
    }
    
    
    so in etwa sieht das bei mir aus und funktioniert wunderbar
     
    19sheriff93 bedankt sich.
  3. 19sheriff93, 14.06.2012 #3
    19sheriff93

    19sheriff93 Threadstarter Junior Mitglied

    Das müsste echt funken danke!
    Dürfte ich noch fragen wie du die Verbindung zur Listview und bzw zu einem Textfeld herstellst? das funktioniert bei mir leider auch noch nicht:huh:
     

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