Question

我之前问过一个问题，但我觉得我说错了。我希望从＆＃34;分数＆＃34;中选择前3个分数。在高分活动中表格并填充3个textViews。

数据库适配器类;

//Primary Key for the score
public static final String KEY_ROWID = "id";
//Field for user score
public static final String KEY_SCORE = "score";

//Database name
private static final String DATABASE_NAME = "SportsQuizDB";
//Database table name
private static final String DATABASE_TABLE = "Score";
//Database version
private static final int DATABASE_VERSION = 1;

private dbHelper dbHelper;
private final Context context;
private SQLiteDatabase sqlDB;

private static class dbHelper extends SQLiteOpenHelper
{
    //Constructor for dbHelper
    public dbHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
        // TODO Auto-generated constructor stub
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        // TODO Auto-generated method stub
        db.execSQL("CREATE TABLE " + DATABASE_TABLE + " (" + 
        KEY_ROWID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
        KEY_SCORE + " INTEGER NOT NULL);"
        );
    }

    //This method is over ridden from its super class.  If the     
    //database it out of date then it is updated in the constructor     
    //and logged here.  Once updated the tables are dropped and     
    //onCreate is recalled.
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE);
        onCreate(db);
    }


} 

public Adapter(Context c)
{
    context = c;
}

public Adapter open()
{
    try{
    dbHelper = new dbHelper(context);
    sqlDB = dbHelper.getWritableDatabase();
    }
    catch (SQLException e)
    {
        Log.e("Open(); ",Log.getStackTraceString(e));
    }
    return this;
}

public Cursor selectTop3()
{
    //I began to attempt the select form the SQLite DB
    //But I am unsure how to use the cursor to populate the TextViews
    String query = "SELECT * FROM "+ DATABASE_TABLE +" ORDER BY " + KEY_SCORE + " DESC ";
    Cursor c = sqlDB.rawQuery(query, null);
    return c;
}

public void close()
{
    dbHelper.close();
}

包含3个TextView的HighScore类。

public class HighScores extends Activity {
TextView result1, result2, result3;

Adapter adapter;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    //Removes Title Bar 
    this.requestWindowFeature(Window.FEATURE_NO_TITLE);
    //Removes Notification Bar
    this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);

    setContentView(R.layout.activity_high_scores);

    result1 = (TextView) findViewById(R.id.result1);
    result2 = (TextView) findViewById(R.id.result2);
    result3 = (TextView) findViewById(R.id.result3);

    fillHighScores();


}

private void fillHighScores() {
    openDB();
    //This it where I wish to populate the three TextViews (result1, result2, result3)

    closeDB();  
}

private void openDB() {
    adapter = new Adapter(this);
    adapter.open();
}

@Override
protected void onDestroy() {
    super.onDestroy();
    closeDB();
}

private void closeDB() {
    adapter.close();
}

@Override
protected void onPause() {
    super.onPause();
}

我现在已经尝试了2天似乎是一个简单的过程。在我看来，android SQLite过于混乱和冗长。如果有人能发光，那将是非常感激的。提前谢谢。

Answer 1

我不确定您要使用适配器完成什么，但您需要的是SQLiteOpenHelper的实例并调用函数getReadableDatabase。使用数据库，您可以查询前3个结果。

这是一个很棒的教程http://www.vogella.com/tutorials/AndroidSQLite/article.html

解析光标可能很痛苦。您可能想要查看几个库。 Green DAO和ORM Lite。

Android：在TextView中显示SQLite记录

1 个答案: