package testCode;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.channels.FileChannel;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.os.Environment;
import android.text.format.DateFormat;
import android.util.Log;
public class DbExportImport {
public static final String TAG = DbExportImport.class.getName();
/** Directory that files are to be read from and written to **/
protected static final File DATABASE_DIRECTORY =
new File(Environment.getExternalStorageDirectory(),"MyDirectory");
/** File path of Db to be imported **/
protected static final File IMPORT_FILE =
new File(DATABASE_DIRECTORY,"MyDb.db");
public static final String PACKAGE_NAME = "com.example.app";
public static final String DATABASE_NAME = "example.db";
public static final String DATABASE_TABLE = "entryTable";
/** Contains: /data/data/com.example.app/databases/example.db **/
private static final File DATA_DIRECTORY_DATABASE =
new File(Environment.getDataDirectory() +
"/data/" + PACKAGE_NAME +
"/databases/" + DATABASE_NAME );
/** Saves the application database to the
* export directory under MyDb.db **/
protected static boolean exportDb(){
if( ! SdIsPresent() ) return false;
File dbFile = DATA_DIRECTORY_DATABASE;
String filename = "MyDb.db";
File exportDir = DATABASE_DIRECTORY;
File file = new File(exportDir, filename);
if (!exportDir.exists()) {
exportDir.mkdirs();
}
try {
file.createNewFile();
copyFile(dbFile, file);
return true;
} catch (IOException e) {
e.printStackTrace();
return false;
}
}
/** Replaces current database with the IMPORT_FILE if
* import database is valid and of the correct type **/
protected static boolean restoreDb(){
if( ! SdIsPresent() ) return false;
File exportFile = DATA_DIRECTORY_DATABASE;
File importFile = IMPORT_FILE;
if( ! checkDbIsValid(importFile) ) return false;
if (!importFile.exists()) {
Log.d(TAG, "File does not exist");
return false;
}
try {
exportFile.createNewFile();
copyFile(importFile, exportFile);
return true;
} catch (IOException e) {
e.printStackTrace();
return false;
}
}
/** Imports the file at IMPORT_FILE **/
protected static boolean importIntoDb(Context ctx){
if( ! SdIsPresent() ) return false;
File importFile = IMPORT_FILE;
if( ! checkDbIsValid(importFile) ) return false;
try{
SQLiteDatabase sqlDb = SQLiteDatabase.openDatabase
(importFile.getPath(), null, SQLiteDatabase.OPEN_READONLY);
Cursor cursor = sqlDb.query(true, DATABASE_TABLE,
null, null, null, null, null, null, null
);
DbAdapter dbAdapter = new DbAdapter(ctx);
dbAdapter.open();
final int titleColumn = cursor.getColumnIndexOrThrow("title");
final int timestampColumn = cursor.getColumnIndexOrThrow("timestamp");
// Adds all items in cursor to current database
cursor.moveToPosition(-1);
while(cursor.moveToNext()){
dbAdapter.createQuote(
cursor.getString(titleColumn),
cursor.getString(timestampColumn)
);
}
sqlDb.close();
cursor.close();
dbAdapter.close();
} catch( Exception e ){
e.printStackTrace();
return false;
}
return true;
}
/** Given an SQLite database file, this checks if the file
* is a valid SQLite database and that it contains all the
* columns represented by DbAdapter.ALL_COLUMN_KEYS **/
protected static boolean checkDbIsValid( File db ){
try{
SQLiteDatabase sqlDb = SQLiteDatabase.openDatabase
(db.getPath(), null, SQLiteDatabase.OPEN_READONLY);
Cursor cursor = sqlDb.query(true, DATABASE_TABLE,
null, null, null, null, null, null, null
);
// ALL_COLUMN_KEYS should be an array of keys of essential columns.
// Throws exception if any column is missing
for( String s : DbAdapter.ALL_COLUMN_KEYS ){
cursor.getColumnIndexOrThrow(s);
}
sqlDb.close();
cursor.close();
} catch( IllegalArgumentException e ) {
Log.d(TAG, "Database valid but not the right type");
e.printStackTrace();
return false;
} catch( SQLiteException e ) {
Log.d(TAG, "Database file is invalid.");
e.printStackTrace();
return false;
} catch( Exception e){
Log.d(TAG, "checkDbIsValid encountered an exception");
e.printStackTrace();
return false;
}
return true;
}
private static void copyFile(File src, File dst) throws IOException {
FileChannel inChannel = new FileInputStream(src).getChannel();
FileChannel outChannel = new FileOutputStream(dst).getChannel();
try {
inChannel.transferTo(0, inChannel.size(), outChannel);
} finally {
if (inChannel != null)
inChannel.close();
if (outChannel != null)
outChannel.close();
}
}
/** Returns whether an SD card is present and writable **/
public static boolean SdIsPresent() {
return Environment.getExternalStorageState().equals(
Environment.MEDIA_MOUNTED);
}
}
