我如何将项目添加到SQLite数据库？ [英] How i can add items to the sqlite database?
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问题描述
我试图使我第一次真正的应用程序，它变成地狱在第二。首先，我试图通过一些教程，了解架构，但不同的教程说的数据库不同的东西，我有点糊涂了。我想说明你在哪里，我实际上是：
I'm trying to make my first true application, it turns to hell in a second. First, I've tried to understand the architecture by making a number of tutorials, but different tutorials say different things about the database, and i'm a bit confused. I'd like to illustrate you where I am actually:
我的数据库帮助：
public class MySQLiteHelper extends SQLiteOpenHelper {
public static final String TABLE_CATEGORIE = "categorie";
public static final String TABLE_SONDAGGI = "sondaggi";
public static final String TABLE_TESTORISPOSTE = "testo_risposte";
public static final String TABLE_RISPOSTE = "risposte";
public static final String COLUMN_ID = "_id";
public static final String COLUMN_NOME = "nome";
public static final String COLUMN_PREF = "preferita";
public static final String COLUMN_CATID = "catid";
public static final String COLUMN_DOMANDA = "domanda";
public static final String COLUMN_SONDID = "sondid";
public static final String COLUMN_RISPOSTA = "risposta";
public static final String COLUMN_RISID = "risid";
public static final String COLUMN_SELEZIONATA = "selezionata";
private static final String DATABASE_NAME = "democracy.db";
private static final int DATABASE_VERSION = 2;
// Database creation sql statement
private static final String DATABASE_CREATE_CATEGORIE = "create table "
+ TABLE_CATEGORIE + "(" + COLUMN_ID
+ " integer primary key autoincrement, " + COLUMN_PREF
+ " integer null, " + COLUMN_NOME
+ " text not null);";
private static final String DATABASE_CREATE_SONDAGGI = "create table "
+ TABLE_SONDAGGI + "(" + COLUMN_ID
+ " integer primary key autoincrement, " + COLUMN_CATID
+ " integer not null, "+ COLUMN_DOMANDA +" text not null);";
private static final String DATABASE_CREATE_TESTORISPOSTE = "create table "
+ TABLE_TESTORISPOSTE + "(" + COLUMN_ID
+ " integer primary key autoincrement, " + COLUMN_SONDID
+ " integer not null, "+ COLUMN_SELEZIONATA
+ " integer, "+ COLUMN_RISPOSTA +" text not null);";
public MySQLiteHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase database) {
database.execSQL(DATABASE_CREATE_CATEGORIE);
database.execSQL(DATABASE_CREATE_SONDAGGI);
database.execSQL(DATABASE_CREATE_TESTORISPOSTE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Log.w(MySQLiteHelper.class.getName(),
"Upgrading database from version " + oldVersion + " to "
+ newVersion + ", which will destroy all old data");
db.execSQL("DROP TABLE IF EXISTS " + TABLE_CATEGORIE);
db.execSQL("DROP TABLE IF EXISTS " + TABLE_SONDAGGI);
db.execSQL("DROP TABLE IF EXISTS " + TABLE_TESTORISPOSTE);
onCreate(db);
}
}
表类，我得到的一个：
public class categorie {
private long id;
private String nome;
private long preferita;
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public String getNome() {
return nome;
}
public void setNome(String nome) {
this.nome = nome;
}
public long getPreferita() {
return preferita;
}
public void setPreferita(long preferita) {
this.preferita = preferita;
}
// Will be used by the ArrayAdapter in the ListView
@Override
public String toString() {
return nome;
}
}
数据源：
public class pollDataSource {
// Database fields
private SQLiteDatabase database;
private MySQLiteHelper dbHelper;
private String[] allCategorieColumns = { MySQLiteHelper.COLUMN_ID,
MySQLiteHelper.COLUMN_PREF, MySQLiteHelper.COLUMN_NOME };
private String[] allSondaggiColumns = { MySQLiteHelper.COLUMN_ID,
MySQLiteHelper.COLUMN_CATID, MySQLiteHelper.COLUMN_DOMANDA };
private String[] allRisposteColumns = { MySQLiteHelper.COLUMN_ID,
MySQLiteHelper.COLUMN_SONDID, MySQLiteHelper.COLUMN_RISPOSTA,
MySQLiteHelper.COLUMN_SELEZIONATA };
public pollDataSource(Context context) {
dbHelper = new MySQLiteHelper(context);
}
public void open() throws SQLException {
database = dbHelper.getWritableDatabase();
}
public void close() {
dbHelper.close();
}
public categorie createCategoria(String categoria) {
ContentValues values = new ContentValues();
values.put(MySQLiteHelper.COLUMN_NOME, categoria);
values.put(MySQLiteHelper.COLUMN_PREF, 0);
long insertId = database.insert(MySQLiteHelper.TABLE_CATEGORIE, null,
values);
Cursor cursor = database.query(MySQLiteHelper.TABLE_CATEGORIE,
allCategorieColumns, MySQLiteHelper.COLUMN_ID + " = " + insertId, null,
null, null, null);
cursor.moveToFirst();
categorie newCategoria = cursorToCategorie(cursor);
cursor.close();
return newCategoria;
}
public void deleteCategoria(categorie categoria) {
long id = categoria.getId();
System.out.println("Categoria cancellata, id: " + id);
database.delete(MySQLiteHelper.TABLE_CATEGORIE, MySQLiteHelper.COLUMN_ID
+ " = " + id, null);
}
public sondaggi createSondaggio(String domanda, int catid) {
ContentValues values = new ContentValues();
values.put(MySQLiteHelper.COLUMN_DOMANDA, domanda);
values.put(MySQLiteHelper.COLUMN_CATID, catid);
long insertId = database.insert(MySQLiteHelper.TABLE_SONDAGGI, null,
values);
Cursor cursor = database.query(MySQLiteHelper.TABLE_SONDAGGI,
allSondaggiColumns, MySQLiteHelper.COLUMN_ID + " = " + insertId, null,
null, null, null);
cursor.moveToFirst();
sondaggi newSondaggio = cursorToSondaggi(cursor);
cursor.close();
return newSondaggio;
}
public void deleteSondaggio(sondaggi sondaggio) {
long id = sondaggio.getId();
System.out.println("Sondaggio cancellato, id: " + id);
database.delete(MySQLiteHelper.TABLE_SONDAGGI, MySQLiteHelper.COLUMN_ID
+ " = " + id, null);
}
public Cursor getAllCategorie() {
List<categorie> categorie = new ArrayList<categorie>();
Cursor cursor = database.query(MySQLiteHelper.TABLE_CATEGORIE,
allCategorieColumns, null, null, null, null, null);
cursor.moveToFirst();
while (!cursor.isAfterLast()) {
categorie categoria = cursorToCategorie(cursor);
categorie.add(categoria);
cursor.moveToNext();
}
// Make sure to close the cursor
// cursor.close();
return cursor;
}
private categorie cursorToCategorie(Cursor cursor) {
categorie categorie = new categorie();
categorie.setId(cursor.getLong(0));
categorie.setPreferita(cursor.getLong(1));
categorie.setNome(cursor.getString(2));
return categorie;
}
private sondaggi cursorToSondaggi(Cursor cursor) {
sondaggi sondaggi = new sondaggi();
sondaggi.setId(cursor.getLong(0));
sondaggi.setDomanda(cursor.getString(1));
sondaggi.setCatid(cursor.getLong(2));
return sondaggi;
}
}
最后，主要活动：
public class MainActivity extends ListActivity {
private pollDataSource datasource;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
datasource = new pollDataSource(this);
datasource.open();
Cursor values = datasource.getAllCategorie();
String[] categorieColumns =
{
MySQLiteHelper.COLUMN_NOME // Contract class constant containing the word column name
};
int[] mWordListItems = { R.id.categoria_label };
SimpleCursorAdapter adapter = new SimpleCursorAdapter(
getApplicationContext(), // The application's Context object
R.layout.single_list_item, // A layout in XML for one row in the ListView
values, // The result from the query
categorieColumns, // A string array of column names in the cursor
mWordListItems, // An integer array of view IDs in the row layout
0); // Flags (usually none are needed)
// Sets the adapter for the ListView
setListAdapter(adapter);
}
// Will be called via the onClick attribute
// of the buttons in main.xml
public void onClick(View view) {
switch (view.getId()) {
case R.id.add:
break;
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
实际上，我试图了解在哪里以及如何添加的东西添加到我的categorie的表的方法......我想我shold创建一个插入的方法，或者也许我只好打电话给categorie类，并使用setNome ...但我真的很迷茫......任何人都可以点我在正确的方向？
先谢谢了。
I'm actually trying to understand where and how to add a method to add things to my categorie's table... I guess I shold create an "insert" method, or maybe i had to call the categorie class and use the setNome... but i'm really confused... could anyone point me in the right direction? thanks in advance.
推荐答案
您可以在很多不同的方式做到这一点。这里有一个：
You can do this in so many different ways. Here's one:
Helper类：
new Database(getWriteableDatabase()).save(someCategorie);
SQL常量：
public static final String TABLE_NAME = "Categorie"
public static final String SAVE = "INSERT INTO "+ TABLE_NAME +
" VALUES (NULL, ?, ?);";
数据库类：
public Database(SQLiteDatabase database) {
this.database = database;
}
public void save(Categorie categorie) {
SQLiteStatement statement = database.compileStatement(SAVE);
statement.bindString(1, categorie.getSomething());
statement.bindLong(2, categorie.getSomethingElse());
statement.execute();
statement.close();
}
下面是另一个：
使用图书馆 https://github.com/novoda/SQLiteProvider
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