Comment récupérer des données de la base de données sqlite dans Android et les afficher dans TextView
J'apprends Android. J'ai un problème et je ne peux pas le résoudre. Je veux récupérer des données d'une base de données existante et les afficher dans un bouton TextView après clic.
Mon code DataBaseHelper ressemble à ceci:
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 ressemble à ceci:
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
}
});
}
}
J'ai fait comme ci-dessus et Eclipse me donne des erreurs.
Database name: cytaty
name of table: cytaty
columns: _id, autor, cytat
Mon code est:
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;
}
}
Et:
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);
}
});
}
Qu'est-ce que je fais mal? Je veux récupérer les données de la base de données et les afficher dans TextView après avoir cliqué sur le bouton. Votre aide serait appréciée.
en cliquant sur le bouton, ouvrez d'abord la base de données, récupérez les données et fermez la base de données comme ceci
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
}
});
}
}
et votre getYourData() dans la classe de base de données serait comme ceci
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;
}
TextView tekst = (TextView) findViewById(R.id.editText1);
Vous ne pouvez pas convertir EditText en TextView.
Vous pouvez utiliser ce code suivant, en fait, il est grossier mais vérifiez-le.
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();
}
Commencez par lancer votre texte d'édition comme ceci:
TextView tekst = (TextView) findViewById(R.id.editText1);
tekst.setText(text);
Et après cela, fermez la base de données pas avant cette ligne ...
myDataBaseHelper.close();