如何显示 SQLite 数据库表？

Question

在我的应用程序中，我使用数据库来显示一些用户信息，我使用 SQLite 数据库浏览器创建了数据库，并将该数据库放在 assets 文件夹中，这就是编码，我想显示这个表.

public class DataBaseHelper extends SQLiteOpenHelper{   
private Context mycontext;
private String DB_PATH = "/data/data/com.slate.game/databases/";    
private static String DB_NAME = "slider.db";//the extension may be .sqlite or .db
public SQLiteDatabase myDataBase;    
public DataBaseHelper(Context context) throws IOException  {
    super(context,DB_NAME,null,1);
    this.mycontext=context;
    boolean dbexist = checkdatabase();
    if(dbexist)  {
        System.out.println("Database exists");
        opendatabase(); 
    }
    else {
        System.out.println("Database doesn't exist");
        createdatabase();
    }
    }
    public void createdatabase() throws IOException{
     boolean dbexist = checkdatabase();
     if(dbexist)   {
        System.out.println(" Database exists.");
    }
    else{ this.getReadableDatabase();
    try{
        copydatabase();
    }
    catch(IOException e)  {
        throw new Error("Error copying database");
      }
     }
    }   
private boolean checkdatabase() {    
    boolean checkdb = false;
    try  {
        String myPath = DB_PATH + DB_NAME;
        File dbfile = new File(myPath);
        checkdb = dbfile.exists();
    }
    catch(SQLiteException e)   {
        System.out.println("Database doesn't exist");
    }
    return checkdb;
}   
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;
    System.out.println("outfilename"+outfilename);
    //Open the empty db as the output stream
    OutputStream myoutput = new FileOutputStream("/data/data/com.slate.game/databases/slider.db");
    // transfer byte to inputfile to 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);
}
public synchronized void close()  {
    if(myDataBase != null){
        myDataBase.close();
    }
    super.close();
}
@Override
public void onCreate(SQLiteDatabase arg0)  {         
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {       
}

请帮我如何显示这个表（数据库）..

Answer 1

我终于从这本书中得到了答案

Beginning.Android.Application.Development.

使用我准备的 SQLite 数据库，我将使用带有 TextView 的 TableLayout 获取行并显示..

这是数据库适配器类

public class DBAdapter3x3  {

public static final String KEY_ROWID = "_id";
public static final String KEY_NAME = "name";
public static final String KEY_MOVES = "moves";
public static final String KEY_TIME = "time";
private static final String TAG = "DBAdapter";
private static final String DATABASE_NAME = "SliderDB3x3.db";
private static final String DATABASE_TABLE = "topscore3x3"; 
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_CREATE = "create table topscore3x3 " +
                                        "(_id integer primary key autoincrement, "
                                        + "name text not null, moves integer not null," 
                                        + "time text not null);";

private final Context context;
private DatabaseHelper DBHelper;
private SQLiteDatabase db;

public DBAdapter3x3(Context ctx)    {
    this.context = ctx;
    DBHelper = new DatabaseHelper(context);
}

private static class DatabaseHelper extends SQLiteOpenHelper    {

    DatabaseHelper(Context context)     {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db)   {
        try  {
            db.execSQL(DATABASE_CREATE);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)   {
        Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
                + newVersion + ", which will destroy all old data");
        db.execSQL("DROP TABLE IF EXISTS contacts");
        onCreate(db);
    }
}

//---opens the database---
public DBAdapter3x3 open() throws SQLException      {

    db = DBHelper.getWritableDatabase();
    return this;
}

//---closes the database---
public void close()   {
    DBHelper.close();
}

//---insert a contact into the database---
public long insertContact(String name, int moves,String time)   {

    ContentValues initialValues = new ContentValues();
    initialValues.put(KEY_NAME, name);
    initialValues.put(KEY_MOVES, moves);
    initialValues.put(KEY_TIME, time);
    return db.insert(DATABASE_TABLE, null, initialValues);
}

//---deletes a particular contact---
public boolean deleteContact(long rowId)    {

    return db.delete(DATABASE_TABLE, KEY_ROWID + "=" + rowId, null) > 0;
}

//---retrieves all the contacts---
public Cursor getAllContacts()  {

    return db.query(DATABASE_TABLE, new String[] {KEY_ROWID, KEY_NAME,
            KEY_MOVES, KEY_TIME}, null, null, null, null, null);
}

//---retrieves a particular contact---
public Cursor getContact(long rowId) throws SQLException    {

    Cursor mCursor = db.query(true, DATABASE_TABLE, new String[] {KEY_ROWID, KEY_NAME, 
                     KEY_MOVES, KEY_TIME}, KEY_ROWID + "=" + rowId, null,null, null, null, null);
    if (mCursor != null) {
        mCursor.moveToFirst();
    }
    return mCursor;
}

//---updates a contact---
public boolean updateContact(long rowId, String name, int moves, String time)   {

    ContentValues args = new ContentValues();
    args.put(KEY_NAME, name);
    args.put(KEY_MOVES, moves);
    args.put(KEY_TIME, time);       
    return db.update(DATABASE_TABLE, args, KEY_ROWID + "=" + rowId, null) > 0;
}
//public Cursor fetchAllNotes() {


public Cursor SortAllRows() {
    return db.query(DATABASE_TABLE, new String[] { KEY_ROWID, KEY_NAME, 
             KEY_MOVES,KEY_TIME}, null, null, null, null, KEY_MOVES + " ASC");
}
}

我在这个活动中使用了数据库

public class TopScore3x3 extends Activity  {

private DBAdapter3x3 db;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.db3x3);      

    db = new DBAdapter3x3(this);        
    getall();    
    delete();

private void delete()  {

    db.open();       
    Cursor c = db.SortAllRows();
    int i=1;
    if (c.moveToFirst())   {        
        do {            
            if(i>10) { db.deleteContact(i); } 
            i++;
        } while (c.moveToNext());
    }
    c.close();
    db.close();
}   

private void getall()  {
    //---get all contacts---
    db.open();
    //db.fetchAllNotes();
    Cursor c = db.SortAllRows();
    int i=1;
    if (c.moveToFirst())   {        
        do {
            DisplayContact(c,i++);
        } while (c.moveToNext());
    }
    c.close();
    db.close();
} 

public void DisplayContact(Cursor c,int row )   {            

     String name11 = c.getString(1) + c.getString(2) + c.getString(3);           
     tv1.setText(name11 );

  }
 } 

Answer 2

使用以下函数从数据库中检索数据

/**
 * This function used to select the records from DB.
 * @param tableName
 * @param tableColumns
 * @param whereClase
 * @param whereArgs
 * @param groupBy
 * @param having
 * @param orderBy
 * @return A Cursor object, which is positioned before the first entry.
 */
public Cursor selectRecordsFromDB(String tableName, String[] tableColumns,String whereClase, String whereArgs[], String groupBy,String having, String orderBy) 
{
    return myDataBase.query(tableName, tableColumns, whereClase, whereArgs,groupBy, having, orderBy);
}

/**
 * select records from db and return in list
 * @param tableName
 * @param tableColumns
 * @param whereClase
 * @param whereArgs
 * @param groupBy
 * @param having
 * @param orderBy
 * @return ArrayList<ArrayList<String>>
 */
public ArrayList<ArrayList<String>> selectRecordsFromDBList(String tableName, String[] tableColumns,String whereClase, String whereArgs[], String groupBy,String having, String orderBy)
{       

    ArrayList<ArrayList<String>> retList = new ArrayList<ArrayList<String>>();
      ArrayList<String> list = new ArrayList<String>();
      Cursor cursor = myDataBase.query(tableName, tableColumns, whereClase, whereArgs,
                groupBy, having, orderBy);        
      if (cursor.moveToFirst()) 
      {
         do 
            {
             list = new ArrayList<String>();
             for(int i=0; i<cursor.getColumnCount(); i++)
             {                   
               list.add( cursor.getString(i) );
             }   
             retList.add(list);
         } while (cursor.moveToNext());
      }
      if (cursor != null && !cursor.isClosed()) {
         cursor.close();
      }
      return retList;

}   

Answer 3

检查这个：http://www.higherpass.com/Android/Tutorials/Accessing-Data-With-Android-Cursors/2/

使用Cursor c = db.rawQuery(sql, null) 获取结果，那里解释了迭代。