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So rufen Sie Daten aus der sqlite-Datenbank in Android ab und zeigen sie in TextView an

Ich lerne Android. Ich habe ein Problem und kann es nicht lösen. Ich möchte Daten aus einer vorhandenen Datenbank abrufen und sie nach dem Klicken in einer TextView anzeigen. 

Mein Code DataBaseHelper sieht folgendermaßen aus:

public class DataBaseHelper extends SQLiteOpenHelper {

            //The Android's default system path of your application database.    
            private static String DB_PATH = "/data/data/in.ekonomia.Android/databases/";     
            private static String DB_NAME = "cytaty";     
            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();  
    }   
    @Override   
    public void onCreate(SQLiteDatabase db) 
    {   }   
    @Override   
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {  }         
    // 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. 

    }

Cytaty.Java sieht so aus:

package in.ekonomia.Android;

import Android.app.Activity;
import Android.os.Bundle;
import Android.view.View;
import Android.widget.Button;


public class cytaty extends Activity {


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.galeria);


        Button bLosuj = (Button) findViewById(R.id.button1);
        bLosuj.setOnClickListener(new View.OnClickListener() {

            public void onClick(View v) {
                // TODO Auto-generated method stub

            }
            });
        }

}

Ich habe es wie oben gemacht und Eclipse gibt mir Fehler. 

Database name: cytaty
name of table: cytaty
columns: _id, autor, cytat 

Mein Code ist: 

public void getData() {
    public String[] getAppCategorydetail() {
        String Table_Name="cytaty";

        String selectQuery = "SELECT  * FROM " + Table_Name;
              SQLiteDatabase db = this.getReadableDatabase();
        Cursor cursor = db.rawQuery(selectQuery, null);
                 String[] data = null;
        if (cursor.moveToFirst()) {
            do {
               // get  the  data into array,or class variable
            } while (cursor.moveToNext());
        }
        db.close();
        return data;
    }

}

Und: 

Button bLosuj = (Button) findViewById(R.id.button1);
    bLosuj.setOnClickListener(new View.OnClickListener() {

        public void onClick(View v) {
            // TODO Auto-generated method stub
            DataBaseHelper myDataBaseHelper = new DataBaseHelper(cytaty.this);
               myDataBaseHelper.openDataBase();
                String text= myDataBaseHelper.getData();//this is the method to query
               myDataBaseHelper.close(); 
            // set text to your TextView 
            TextView tekst = (TextView) findViewById(R.id.editText1);
            tekst.setText(text);
        }
        });
    }

Was mache ich falsch? Ich möchte Daten aus der Datenbank abrufen und nach dem Klicken in TextView anzeigen. Ihre Hilfe wäre dankbar.

12
Tomeksss

Öffnen Sie zunächst die Datenbank, rufen Sie die Daten ab und schließen Sie die Datenbank auf diese Weise

public class cytaty extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.galeria);

        Button bLosuj = (Button) findViewById(R.id.button1);
        bLosuj.setOnClickListener(new View.OnClickListener() {

        public void onClick(View v) {
            myDatabaseHelper = new DatabaseHelper(cytaty.this);
            myDatabaseHelper.openDataBase();

            String text = myDatabaseHelper.getYourData(); //this is the method to query

            myDatabaseHelper.close(); 
            // set text to your TextView
            }
        });
    }
}

und Ihre getYourData() in der Datenbankklasse wäre so

public String[] getAppCategoryDetail() {

    final String TABLE_NAME = "name of table";

    String selectQuery = "SELECT  * FROM " + TABLE_NAME;
    SQLiteDatabase db  = this.getReadableDatabase();
    Cursor cursor      = db.rawQuery(selectQuery, null);
    String[] data      = null;

    if (cursor.moveToFirst()) {
        do {
           // get the data into array, or class variable
        } while (cursor.moveToNext());
    }
    cursor.close();
    return data;
}
25
Rajendra
TextView tekst = (TextView) findViewById(R.id.editText1); 

Sie können EditText nicht in TextView umwandeln.

4
ChamalPradeep

Sie können den folgenden Code verwenden, der zwar grob ist, aber bitte überprüfen

db = openOrCreateDatabase("sms.db", SQLiteDatabase.CREATE_IF_NECESSARY, null);
Cursor cc = db.rawQuery("SELECT * FROM datatable", null);
final ArrayList<String> row1 = new ArrayList<String>();
final ArrayList<String> row2 = new ArrayList<String>();

if(cc!=null) {
    cc.moveToFirst();   
    startManagingCursor(cc);
    for (int i=0; i<cc.getCount(); i++) {

    String number  = cc.getString(0);
    String message = cc.getString(1);
    row1.add(number);
    row2.add(message);

    final EditText et3 = (EditText) findViewById(R.id.editText3);
    final EditText et4 = (EditText) findViewById(R.id.editText4);
    Button bt1 = (Button) findViewById(R.id.button1);
    bt1.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub

            switch (v.getId()) {
                case R.id.button1:
                    et3.setText(row1.get(count));
                    et4.setText(row2.get(count));
                    count++;
                    break;
                default:
                    break;
            }

        }
    });

cc.moveToNext();
}
3
Mehdi

Zuerst werfen Sie Ihren Edit-Text folgendermaßen aus: 

TextView tekst = (TextView) findViewById(R.id.editText1);
tekst.setText(text);

Und danach die DB nicht vor dieser Zeile schließen ...

 myDataBaseHelper.close(); 
0
ziddi609