我什至不确定我的代码结构是否合适。我有一个以显示活动 Results.java 结尾的琐事游戏。然后我有一个带有 DatabaseHelper 子类的 Highscores.java，它被调用以将当前游戏分数插入到 Highscores 数据库表中。下面是我的 Highscores.java 类，其中注释了错误。
另外，如果我应该以不同的方式构建这些类——例如，将 DatabaseHelper 从一个子类移动到它自己的类——请告诉我。我很难实现这个 SQLite 数据库表。
高分.java
public class Highscores extends Activity {
Context context;
Button btn1;
DatabaseHelper dh;
SQLiteDatabase db;
private static final int DATABASE_VERSION = 1;
private static final String DB_NAME = "test3";
private static final String DB_PATH = "/data/data/com.example.test/databases/";
private static final String TABLE = "HighscoresList";
// Table columns names.
private static final String RANK = "_id";
private static final String SCORE = "score";
private static final String PERCENTAGE = "percentage";
TableLayout table;
TableRow rowHeader, row1, row2, row3, row4, row5, row6, row7, row8, row9, row10;
TextView rank, percentage, score;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.highscoresmain);
Button btn1 = (Button)findViewById(R.id.homeBtn);
btn1.setOnClickListener(new OnClickListener() {
public void onClick(View arg0) {
Intent intent = new Intent(Highscores.this, MainMenu.class);
startActivity(intent);
}
});
DatabaseHelper(context); //Error: The method DatabaseHelper(Context) is undefined for the type Highscore.
}
public class DatabaseHelper extends SQLiteOpenHelper {
public DatabaseHelper(Context context) {
super(context, DB_NAME, null, DATABASE_VERSION);
db = getWritableDatabase();
TableRow rowHeader = new TableRow(context);
TableRow row1 = new TableRow(context);
TableRow row2 = new TableRow(context);
TableRow row3 = new TableRow(context);
TableRow row4 = new TableRow(context);
TableRow row5 = new TableRow(context);
TableRow row6 = new TableRow(context);
TableRow row7 = new TableRow(context);
TableRow row8 = new TableRow(context);
TableRow row9 = new TableRow(context);
TableRow row10 = new TableRow(context);
TextView rank = new TextView(context);
TextView percentage = new TextView(context);
TextView score = new TextView(context);
TextView r1r = new TextView(context);
TextView r1p = new TextView(context);
TextView r1s = new TextView(context);
Cursor c_percentage = db.rawQuery("SELECT " + PERCENTAGE + " FROM " + TABLE + ";", null);
Cursor c_score = db.rawQuery("SELECT " + SCORE + " FROM " + TABLE + ";", null);
rank.setText("TEST - COLUMN RANK");
percentage.setText("TEST - COLUMN PERCENTAGE");
score.setText("TEST - COLUMN SCORE");
r1r.setText("test..rank");
r1p.setText("teset...percentage");
r1s.setText("test...scoree");
rowHeader.addView(rank);
rowHeader.addView(percentage);
rowHeader.addView(score);
row1.addView(r1r);
row1.addView(r1p);
row1.addView(r1s);
table.addView(rowHeader);
table.addView(row1);
table.addView(row2);
table.addView(row3);
table.addView(row4);
table.addView(row5);
table.addView(row6);
table.addView(row7);
table.addView(row8);
table.addView(row9);
table.addView(row10);
table = (TableLayout)findViewById(R.id.tableLayout);
}
//Check if new record makes the top 10.
public boolean check(long score, int percentage) {
Cursor c1 = db.rawQuery("SELECT " + PERCENTAGE + " FROM " + TABLE + " WHERE " + PERCENTAGE + "=" + percentage + ";", null);
Cursor c2 = db.rawQuery("SELECT " + SCORE + " FROM " + TABLE + ";", null);
if(c1 != null && c2 != null) {
if(c1.getCount() > 0) {
c2.moveToFirst();
int i = 0;
do {
i++;
long x = c2.getLong(c2.getColumnIndex("SCORE"));
if(x < percentage) {
if(c2.getCount() == 9) {
//Delete last record in high score and insert at index.
db.rawQuery("DELETE FROM " + TABLE + " WHERE " + RANK + " = 10;", null);
db.rawQuery("INSERT INTO " + TABLE + "VALUES (" + i + ", " + score + ", " + percentage + ");", null);
return true;
} else {
//No deletion - just insert.
db.rawQuery("INSERT INTO " + TABLE + "VALUES (" + i + ", " + score + ", " + percentage + ");", null);
return true;
}
} else {
return false;
}
} while (c2.moveToNext());
} else {
return false;
}
} else {
return false;
}
}
//Insert new record.
public long insert(long score, int percentage) {
ContentValues values = new ContentValues();
values.put(SCORE, score);
values.put(PERCENTAGE, percentage);
return db.insert(TABLE, null, values);
}
public void openDatabase() throws SQLException {
//Open the database.
String myPath = DB_PATH + DB_NAME;
db = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
}
public synchronized void close() {
if(db != null) {
db.close();
}
super.close();
}
public void onCreate(SQLiteDatabase db) {
db.execSQL("CREATE TABLE " + TABLE + " ("
+ RANK + " INTEGER PRIMARY KEY AUTOINCREMENT,"
+ SCORE + " LONG,"
+ PERCENTAGE + " INTEGER"
+ ");");
}
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {}
}