我是Android工作室的新手，但多年来一直在Netbeans上编写Java代码。我一直在努力研究如何将SQLite链接到Android Studio。我设法让DatabaseHelper代码工作，但我现在仍然坚持我应该做的事情？数据库已在SQLitebrowser上创建。这是databasehelper类：
public class DataBaseHelper extends SQLiteOpenHelper {
String DB_PATH = null;
private static String DB_NAME = "Restaurant";
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.
*/
public DataBaseHelper(Context context) {
super(context, DB_NAME, null, 1);
this.myContext = context;
this.DB_PATH = "/data/data/" + context.getPackageName() + "/" + "databases";
}
/**
* Creates an empty database on the system and rewrites it with my database.
* */
public void createDataBase() throws IOException{
boolean dbExist = checkDataBase();
if(dbExist){
}else{
//By calling this method and empty database will be created into the default system path
//of the 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 my database from the local assets-folder to the just created empty database in the
* system folder, from where it can be accessed and handled by java
*/
private void copyDataBase() throws IOException{
//Open the 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);
}
//Closes them
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) {
if (newVersion>oldVersion){
try{
copyDataBase();
} catch
(IOException e){
e.printStackTrace();
}
}
}
}
我现在打算如何在列表中查看此内容？