We Keep Coding

Database copied from assets is empty (no tables) on api 28

I use the following code to export the database file to the phone memory. It works fine on Android 24 , but on API 28 it only gives an empty file:
public void exportDatabse() {
try {
if (sd.canWrite()) {
String backupDBPath = "nameBCK.db";
File currentDB = new File(MainActivity.this.getDatabasePath("dataBaseName.db").getPath());
File backupDB = new File(sd, backupDBPath);
if (currentDB.exists()) {
FileChannel src = new FileInputStream(currentDB).getChannel();
FileChannel dst = new FileOutputStream(backupDB).getChannel();
dst.transferFrom(src, 0, src.size());
src.close();
dst.close();
Toast.makeText(this,getString(R.string.stSuccess2),
Toast.LENGTH_LONG).show();
}
}
else {
REQUEST_TYPE=0;
ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, REQUEST_CODE);}
} catch (Exception e) {
Toast.makeText(this,getString(R.string.stFaild),Toast.LENGTH_LONG).show();
}
}
And also I use onRequestPermissionsResult to request permission to write to storage.
#Override
public void onRequestPermissionsResult(int requestCode, String permissions[], int[] grantResults) {
switch (requestCode) {
case REQUEST_CODE:
if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
if (REQUEST_TYPE==0) exportDatabse();
if (REQUEST_TYPE==1) importDB();
} else {
if (REQUEST_TYPE==0) Toast.makeText(this,getString(R.string.stFaild2),Toast.LENGTH_LONG).show();
if (REQUEST_TYPE==1) Toast.makeText(this,getString(R.string.stFaild3),Toast.LENGTH_LONG).show();
Log.e("value", "Permission Denied, You cannot use local drive .");
}
break;
default:
throw new IllegalStateException("Unexpected value: " + requestCode);
}
}

I have already answered this question. This problem only occurs on Android 28.
link
public class DataBase extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "database.db";
private static String DATABASE_PATH = "";
private static String LAST_DATABASE_PATH = "";
private SQLiteDatabase mDataBase;
private final Context ctx;
public DataBase2(#Nullable Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
DATABASE_PATH = context.getDatabasePath(DATABASE_NAME).getPath();
this.ctx = context;
if (!checkIfDBExists()) {
createDataBase();
}
File dbFile = new File(Environment.getDataDirectory().getPath()+"/data/"+ BuildConfig.APPLICATION_ID +"/databases");
if (dbFile.isDirectory()) {
String[] child = dbFile.list();
assert child != null;
for (int i = 0; i < child.length; i++) {
if (!(child[i].equals("database.db") || child[i].equals(DATABASE_NAME))) {
new File(dbFile, child[i]).delete();
}
}
}
}
public void createDataBase() {
this.getReadableDatabase();
this.close();
try {
copyDataBase();
} catch (Exception e) {
e.printStackTrace();
}
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
try {
File DbFile = ctx.getDatabasePath(DATABASE_NAME);
if (DbFile.exists()) {
copyDataBase();
}
} catch (Exception e) {
e.printStackTrace();
}
}
private boolean checkIfDBExists() {
File dbFile = new File(DATABASE_PATH);
return dbFile.exists();
}
public void openDataBase() {
close();
mDataBase = SQLiteDatabase.openDatabase(DATABASE_PATH, null, CREATE_IF_NECESSARY);
}
private void copyDataBase() throws IOException {
InputStream mInput = ctx.getAssets().open("database.db");
String outfileName = DATABASE_PATH;
OutputStream mOutput = new FileOutputStream(outfileName);
byte[] buffer = new byte[1024];
int mLength;
while ((mLength = mInput.read(buffer)) > 0) {
mOutput.write(buffer, 0, mLength);
}
mOutput.flush();
mInput.close();
mOutput.close();
}
#Override
public void onCreate(SQLiteDatabase db) {
}
#Override
public synchronized void close() {
if (mDataBase != null)
mDataBase.close();
SQLiteDatabase.releaseMemory();
super.close();
}
}

I found the solution in two things
The First disable Write Ahead Logging using use the SQliteDatabase like said here:
Environment.getExternalStorageDirectory() deprecated in API level 29 java
The Secound use getExternalFilesDir(), getExternalCacheDir(), or getExternalMediaDir() (methods on Context) instead of Environment.getExternalStorageDirectory() ....like said here:
Environment.getExternalStorageDirectory() deprecated in API level 29 java
This two things solved the issue for me.

External database access, my app crashes

Yes I have searched for many solutions for days. My still persisting problem is my app crashes at start when I am trying to access an external database (created through "DB Browser for Sqlite" named "test.db").
The sole purpose is of course to prepopulate my app with some data.
I have kept the database file on assets folder in android studio. Finally I have implemented a helper class to access the database.
Here is the helper class:
public class DataBaseHelper extends SQLiteOpenHelper {
private static final String DATABASE_NAME = "test.db";
private static final int DATABASE_VERSION = 1;
private static String DATABASE_PATH = "";
private SQLiteDatabase myDataBase;
private final Context myContext;
public DataBaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
this.myContext = context;
if (Build.VERSION.SDK_INT >= 17) {
DATABASE_PATH = context.getApplicationInfo().dataDir + "/databases/";
} else {
DATABASE_PATH = "/data/data/" + context.getPackageName() + "/databases/";
}
}
#Override
public void onCreate(SQLiteDatabase db) {
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
public void createDatabase() throws IOException {
createDB();
}
private void createDB() {
boolean dbExists = checkDatabase();
if (dbExists) {
//do nothing
} else {
this.getReadableDatabase();
try {
copyDatabase();
} catch (IOException ie) {
throw new Error("Error copying database");
}
}
}
private boolean checkDatabase() {
SQLiteDatabase checkDB = null;
try {
String myPath = DATABASE_PATH + DATABASE_NAME;
checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
checkDB.setLocale(Locale.getDefault());
} catch (SQLiteException e) {
throw new Error("SQLite exception");
}
if (checkDB != null) {
checkDB.close();
}
return checkDB != null;
}
private void copyDatabase() throws IOException {
InputStream myInput = null;
OutputStream myOutput = null;
String outFileName = DATABASE_PATH + DATABASE_NAME;
try{
myInput = myContext.getAssets().open(DATABASE_NAME);
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();
}catch (IOException ie){
throw new Error("Copydatabase run error ");
}
}
#Override
public synchronized void close() {
if(myDataBase != null){
myDataBase.close();
}
super.close();
}
}
In the Main activity I have just called the createDatabase() method of the helper class. The code being below:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
DataBaseHelper myDbHelper = new DataBaseHelper(this);
try{
myDbHelper.createDatabase();
}catch (IOException ioe){
throw new Error("Unable to CREATE DATABASE");
}
}
}
The logcat indicates the problem as:
AndroidRuntime: FATAL EXCEPTION: main java.lang.Error: SQLite
exception at DataBaseHelper.checkDatabase(DataBaseHelper.java:79) at
DataBaseHelper.createDB(DataBaseHelper.java:59) at
DataBaseHelper.createDatabase(DataBaseHelper.java:55) at
MainActivity.onCreate(MainActivity.java:18)
which points to my checkDatabase() method. But now I am not able to sort out the problem.
I am using Android Studio 3.0.1, DB Browser for Sqlite 3.10.1, Min API level used 17.
Please Help!

Try This
public static final String DATABASE_NAME = "abc.db";
public final static String DATABASE_PATH = "/data/data/"+ PACKAGE_NAME +
"/databases/";
public static final int DATABASE_VERSION = 1;
public void createDatabase() {
boolean dbExist1 = checkDataBase();
if (!dbExist1) {
this.getReadableDatabase();
try {
this.close();
copyDataBase();
} catch (IOException e) {
throw new Error("Error copying database");
}
}
}
// Check database already exist or not
private boolean checkDataBase() {
boolean checkDB = false;
try {
String myPath = DATABASE_PATH + DATABASE_NAME;
File dbfile = new File(myPath);
checkDB = dbfile.exists();
} catch (SQLiteException e) {
}
return checkDB;
}
// Copies your database from your local assets-folder to the just created
// empty database in the system folder
public void copyDataBase() throws IOException {
String outFileName = DATABASE_PATH + DATABASE_NAME;
OutputStream myOutput = new FileOutputStream(outFileName);
InputStream myInput = mContext.getAssets().open(DATABASE_NAME);
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer)) > 0) {
myOutput.write(buffer, 0, length);
}
myInput.close();
myOutput.flush();
myOutput.close();
}

onUpgrade() and onCreate() method do not invoke when creating a new version of database in SQLiteOpenHelper

I am trying to create a new version of database in my android app. But although I change the version of database from previous version (2) to a new version (3) it doesn't invoke onUpgrade() and onCreate() . It just invoke three times the constructor. I do not understand why constructor invoked three times and also why onUpgrade() and onCreate() did not invoke?
I also tried with new database version code but result is same.
Here is my code.
public class DatabaseHelper extends SQLiteOpenHelper {
private static String PACKAGE_NAME;
private static String DB_PATH;
private static String DB_NAME = "mydata.db";
private SQLiteDatabase myDataBase;
private final Context myContext;
public DatabaseHelper(Context context) {
super(context, DB_NAME, null, 3);
this.myContext = context;
Log.e("UPDATED3", "CONSTRUCTOR");
PACKAGE_NAME = myContext.getPackageName();
DB_PATH = "/data/data/" + PACKAGE_NAME + "/databases/";
}
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");
}
}
}
private boolean checkDataBase() {
SQLiteDatabase checkDB = null;
try {
String myPath = DB_PATH + DB_NAME;
checkDB = SQLiteDatabase.openDatabase(myPath, null,
SQLiteDatabase.OPEN_READWRITE);
} catch (SQLiteException e) {
// database does't exist yet.
}
if (checkDB != null) {
checkDB.close();
}
return checkDB != null ? true : false;
}
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_READWRITE);
}
#Override
public synchronized void close() {
if (myDataBase != null)
myDataBase.close();
super.close();
}
#Override
public void onCreate(SQLiteDatabase db) {
Log.e("UPDATED3", "ONCREATE");
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Log.e("UPDATED3", "UPDATED THE DATABASE");
}
}
I use my database this(showing below) way in any activity.
DatabaseHelper databaseHelper = new DatabaseHelper(getApplicationContext());
try {
databaseHelper.createDataBase();
databaseHelper.openDataBase();
} catch (IOException e) {
Toast.makeText(getApplicationContext(), "Error: " + e.getMessage(),
Toast.LENGTH_LONG).show();
e.printStackTrace();
}

android sqlite: How to select differet table data in different database

I have imported two databases (one is omstar0 which have a table omstar, another is omstar1 which have a table omstarline) which were stored in asset file in sdcard of android. android sqlite: How to select differet table data in different database? I mean I want to select all the data in two databases. The following is my code:
public class DBManager {
private Context context;
public final String DB_PATH2 =
android.os.Environment.getExternalStorageDirectory().getAbsolutePath()+"/tianke";
private final String DB_NAME = "omstar0.db";
private SQLiteDatabase database;
private final int BUFFER_SIZE = 1024;
DBManager(Context context) {
this.context = context;
}
public SQLiteDatabase openDatabase() {
for(int i = 0; i<2; i++) {
File dbFile = new File(DB_PATH2+"/omstar"+String.valueOf(i)+".db");
if(!dbFile.exists()){
//InputStream is = this.context.getResources().openRawResource(R.raw.);
try {
//创建目录
File pmsPaht = new File(DB_PATH2);
Log.i("pmsPaht", "pmsPaht: "+pmsPaht.getPath());
pmsPaht.mkdirs();
AssetManager am = this.context.getAssets();
InputStream is = am.open("/omstar"+String.valueOf(i)+".db");
FileOutputStream fos = new FileOutputStream(dbFile);
byte[] buffer = new byte[BUFFER_SIZE];
int count = 0;
while ((count = is.read(buffer)) > 0) {
fos.write(buffer, 0, count);
}
fos.flush();
fos.close();
is.close();
am.close();
}catch (IOException e) {
e.printStackTrace();
}
}
database = SQLiteDatabase.openOrCreateDatabase(dbFile, null);
}
System.out.println("2: sucesseful");
return database;
}
//http://jalhaskazakhlike.lofter.com/post/3f320a_15df9b3
//http://www.cnblogs.com/xiaowenji/archive/2011/01/03/1925014.html
public void closeDatabase() {
if (database!=null){
this.database.close();
}
}
}
public class SDDatabaseActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button create = (Button) findViewById(R.id.button1);
Button query = (Button) findViewById(R.id.button2);
create.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
createDB();
}
});
query.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
queryDB();
}
});
}
public void createDB()
{
DBManager dbm = new DBManager(this);
dbm.openDatabase();
dbm.closeDatabase();
}
public void queryDB()
{
String sql = "select * from omstar";
DBManager dbm = new DBManager(this);
SQLiteDatabase db = dbm.openDatabase();
Cursor cur = db.rawQuery(sql, null);
while (cur.moveToNext())
{
//String id = cur.getColumnName(1);
//float la = cur.ge;
//float id = cur.getColumnName(1);
int id = cur.getInt(0);
String name = cur.getString(1);
String email = cur.getString(2);
Log.i("latitude", "id："+id);
System.out.println("id:"+id);
System.out.println("name:"+name);
System.out.println("Email:"+email);
}
cur.close();
db.close();
}
}

SELECT Columnname FROM Database1.Table ,Database2.Table
WHERE
Database1.Table.Column(Primary Key) = Database2.Table.Column(Primary Key);

get others column value on onItemSelected in Android

My Tbl_Driver have 3 columns _id,Driver_Code,Driver_Name
How do i able to get the Driver_Name when the Spinner OnItemSelected, because The Spinner will only show Driver_Code
public void DriverDatabaseConn(){
DataBaseHelper myDbHelper = new DataBaseHelper(this.getApplicationContext());
myDbHelper = new DataBaseHelper(this);
try {
myDbHelper.createDataBase();
} catch (IOException ioe) {
throw new Error("Unable to create database");
}
try {
myDbHelper.openDataBase();
}catch(SQLException sqle){
throw sqle;
}
SQLiteDatabase db = myDbHelper.getReadableDatabase();
//SQLiteDatabase db = SQLiteDatabase.openDatabase("/data/data/com.example.abc2/databases/DB_BusData", null, 0);
Cursor c = db.rawQuery("SELECT * FROM Tbl_Driver", null);
//=====Add Additional=====
MatrixCursor extras = new MatrixCursor(new String[] { "_id", "Driver_Code" , "Driver_Name"});
extras.addRow(new String[] { "-1", "< Select Driver Code >","< Select Driver >" });
//extras.addRow(new String[] { "-2", "Empty Template","BB" });
Cursor[] cursors = { extras, c };
c = new MergeCursor(cursors);
//===========================
startManagingCursor(c);
//create an array to specify which fields we want to display
String[] from = new String[]{"Driver_Code"};
//create an array of the display item we want to bind our data to
int[] to = new int[]{android.R.id.text1};
//create simple cursor adapter
SimpleCursorAdapter adapter = new SimpleCursorAdapter(this, android.R.layout.simple_spinner_item, c, from, to );
adapter.setDropDownViewResource( android.R.layout.simple_spinner_dropdown_item );
//get reference to our spinner
Spinner s = (Spinner) findViewById( R.id.DriverSpin);
s.setAdapter(adapter);
s.setOnItemSelectedListener(
new OnItemSelectedListener() {
public void onItemSelected(
AdapterView<?> parent, View view, int position, long id) {
Spinner s = (Spinner) findViewById( R.id.DriverSpin);
TextView textView = (TextView)s.getSelectedView();
String result = textView.getText().toString();
Log.d(null,"Spinner1: position=" + result + " id=" + id);
global.Driver_ID = id;
global.Driver_Code = result;
// at here how i can get the Driver_Name column's value at here?
}
public void onNothingSelected(AdapterView<?> parent) {
Log.d(null,"Spinner1: unselected");
}
});
//db.close();
//myDbHelper.close(); //cannot close, otherwise after logout the spinner will blank
}
DataBaseHelper.java
package com.example.abc2;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import android.content.Context;
import android.database.SQLException;
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/com.example.abc2/databases/";
private static String DB_NAME = "DB_BusData";
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.
}

I have rewrite your DatabaseHelpe and a Test Activity:
public class DataBaseHelper {
private static final String DB_NAME = "DB_BusData";
public static final String TABLE_NAME = "Tbl_Driver";
private Context context;
private String path;
private SQLiteDatabase database;
private boolean isInitializing = false;
public DataBaseHelper(Context context) {
this.context = context;
this.path = context.getDatabasePath(DB_NAME).getAbsolutePath();
if (TextUtils.isEmpty(this.path)) {
throw new IllegalArgumentException("database can't be null");
}
}
public SQLiteDatabase getReadableDatabase() {
synchronized (this) {
checkAndCopyDatabase();
return getDatabaseLocked(false);
}
}
/**
* Attention：just support readable database until now
*
* #return
*/
public SQLiteDatabase getWriteableDatabase() {
synchronized (this) {
checkAndCopyDatabase();
return getDatabaseLocked(true);
}
}
private void checkAndCopyDatabase() {
File file = new File(this.path);
if (file.exists() && file.length() > 0) {
Log.d("TAG", "db already exist");
} else {
try {
InputStream is = context.getAssets().open(DB_NAME);
copyStreamToFile(is, new File(this.path));
} catch (IOException e) {
e.printStackTrace();
}
}
}
private static final void copyStreamToFile(InputStream inputStream, File file) {
ensureDir(file);
FileOutputStream fos = null;
try {
fos = new FileOutputStream(file);
byte[] buffer = new byte[2048];
int read = 0;
while ((read = inputStream.read(buffer)) > 0) {
fos.write(buffer, 0, read);
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
quietClose(inputStream);
quietClose(fos);
}
}
private static final void ensureDir(File file) {
if (file != null && (file = file.getParentFile()) != null && !file.exists()) {
file.mkdirs();
}
}
private static final void quietClose(final Closeable closeable) {
if (closeable != null) {
try {
closeable.close();
} catch (final IOException e) {
}
}
}
private SQLiteDatabase getDatabaseLocked(boolean writeable) {
if (this.database != null) {
if (!this.database.isOpen()) {
database = null;
} else if (!writeable || !database.isReadOnly()) {
return database;
}
}
if (isInitializing) {
throw new IllegalArgumentException("getDatabase called recursively");
}
SQLiteDatabase db = this.database;
try {
isInitializing = true;
if (db != null && writeable && db.isReadOnly()) {
if (db.isOpen()) {
db.close();
}
db = null;
}
try {
db = SQLiteDatabase.openDatabase(this.path, null,
writeable ? SQLiteDatabase.OPEN_READWRITE : SQLiteDatabase.OPEN_READONLY);
} catch (SQLiteException e) {
e.printStackTrace();
}
this.database = db;
return db;
} finally {
isInitializing = false;
if (db != null && db != database) {
db.close();
}
}
}
public static class Driver implements BaseColumns {
long id;
String code;
String name;
static final String CODE_CLOMN_NAME = "Driver_Code";
static final String NAME_CLOMN_Name = "Driver_Name";
#Override
public String toString() {
return name;
}
}
public List<Driver> queryAllDriver() {
List<Driver> drivers = null;
SQLiteDatabase db = getReadableDatabase();
if (db != null) {
Cursor cursor = null;
try {
cursor = db.query(TABLE_NAME, null, null, null, null, null, null);
if(cursor != null && cursor.moveToFirst()) {
do {
final long id = cursor.getLong(cursor.getColumnIndex(Driver._ID));
final String code = cursor.getString(cursor.getColumnIndex(Driver.CODE_CLOMN_NAME));
final String name = cursor.getString(cursor.getColumnIndex(Driver.NAME_CLOMN_Name));
Driver driver = new Driver();
driver.id = id;
driver.code = code;
driver.name = name;
if(drivers == null)
drivers = new ArrayList<DataBaseHelper.Driver>();
drivers.add(driver);
} while(cursor.moveToNext());
}
} catch (SQLiteException e) {
e.printStackTrace();
} finally {
if(cursor != null)
cursor.close();
}
db.close();
}
return drivers;
}
}
The DB open and operation code is above, then I write a Test Activity:
public class MainActivity extends Activity implements OnItemSelectedListener {
private List<Driver> drivers;
private Spinner spinner;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
spinner = (Spinner) findViewById(R.id.spinner);
spinner.setOnItemSelectedListener(this);
new DBTask().execute();
}
class DBTask extends AsyncTask<Void, Void, List<Driver>> {
#Override
protected List<Driver> doInBackground(Void... params) {
DataBaseHelper dbHelper = new DataBaseHelper(MainActivity.this);
return dbHelper.queryAllDriver();
}
#Override
protected void onPostExecute(List<Driver> result) {
bindSpinner(result);
}
}
private void bindSpinner(List<Driver> drivers) {
this.drivers = drivers != null ? drivers : new ArrayList<DataBaseHelper.Driver>(0);
ArrayAdapter<Driver> adapter = new ArrayAdapter<DataBaseHelper.Driver>(this,
android.R.layout.simple_spinner_item, this.drivers);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner.setAdapter(adapter);
}
#Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
if (this.spinner != null && position >= 0 && position < this.drivers.size()) {
Driver driver = drivers.get(position);
Toast.makeText(this, "selected: driver=" + driver.name + ", code=" + driver.code,
Toast.LENGTH_SHORT).show();
}
}
#Override
public void onNothingSelected(AdapterView<?> parent) {
Toast.makeText(this, "nothing selected", Toast.LENGTH_SHORT).show();
}
}
The Test Activity is works fine for me, I use the database that I simulated. I think you can't store spinner item in database, how many item in spinner? 10? 100 ? 1000?
You can move query data outside DataBaseHelper.java like this:
private List<Driver> queryAllDriver() {
List<Driver> drivers = null;
DataBaseHelper helper = new DataBaseHelper(this);
SQLiteDatabase db = helper.getReadableDatabase();
if (db != null) {
Cursor cursor = null;
try {
cursor = db.query(DataBaseHelper.TABLE_NAME, null, null, null, null, null, null);
if(cursor != null && cursor.moveToFirst()) {
do {
final long id = cursor.getLong(cursor.getColumnIndex(Driver._ID));
final String code = cursor.getString(cursor.getColumnIndex(Driver.CODE_CLOMN_NAME));
final String name = cursor.getString(cursor.getColumnIndex(Driver.NAME_CLOMN_Name));
Driver driver = new Driver();
driver.id = id;
driver.code = code;
driver.name = name;
if(drivers == null)
drivers = new ArrayList<DataBaseHelper.Driver>();
drivers.add(driver);
} while(cursor.moveToNext());
}
} catch (SQLiteException e) {
e.printStackTrace();
} finally {
if(cursor != null)
cursor.close();
}
db.close();
}
return drivers;
}