[英]source not found when creating object
我想在类GolferDBManager中有一个方法返回我正在从SQLLite db构造的对象数组。 当我尝试构建数组时,方法中出现“ 未找到源”错误。
public Golfer[] retrieveGolfers(){
String[] columns = new String[]{"golfer_name", "golfer_init", "usga_index"};
Cursor cursor = db.query(true, DB_TABLE, columns, null, null, null, null, null, null, null);
cursor.moveToFirst();
int i = 0;
while (cursor.isAfterLast() == false) {
Golfer tGolfer = new Golfer(cursor.getString(0), cursor.getString(1), cursor.getFloat(2));
lGolfers[i] = new Golfer(cursor.getString(0), cursor.getString(1), cursor.getFloat(2));
cursor.moveToNext();
}
if (cursor != null && !cursor.isClosed()) {
cursor.close();
}
return lGolfers;
}
lGolfers在类定义中的定义为:
public class GolferDBManager {
public static final String DB_NAME = "golfgames";
public static final String DB_TABLE = "golfers";
public static final int DB_VERSION = 1;
private static final String CREATE_TABLE = "CREATE TABLE " + DB_TABLE + " (index INTEGER PRIMARY KEY, golfer_name TEXT, golfer_init TEXT, usga_index DOUBLE);";
private SQLHelper helper;
private SQLiteDatabase db;
private Context context;
private Golfer lGolfers[];
的
Golfer tGolfer = new Golfer(cursor.getString(0), cursor.getString(1), cursor.getFloat(2));
线工作正常。 我出于调试目的添加了它。 下一行生成“ 找不到源”错误。 我知道Golfer类的构造函数在那里,因为我只是在上一行中使用过。
这是调用所有这些代码的代码:
public class ReadGolfers extends Activity {
public Golfer Golfers[];
private GolferDBManager mydManager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_read_golfers);
mydManager = new GolferDBManager(this);
mydManager.openReadable();
Golfers = mydManager.retrieveGolfers();
mydManager.retrieveGolfers();
mydManager.close();
}
}
谁能帮我了解为什么这不起作用?
谢谢。
事后,我更改了将对象数组传递给它的方法,如下所示:
public void retrieveGolfers(Golfer lgolfers[]){
String[] columns = new String[]{"golfer_name", "golfer_init", "usga_index"};
Cursor cursor = db.query(true, DB_TABLE, columns, null, null, null, null, null, null, null);
cursor.moveToFirst();
int i = 0;
while (cursor.isAfterLast() == false) {
lgolfers[i] = new Golfer(cursor.getString(0), cursor.getString(1), cursor.getFloat(2));
cursor.moveToNext();
}
if (cursor != null && !cursor.isClosed()) {
cursor.close();
}
}
仍然没有喜悦。
实际上这整行是错误的:
private Golfer lGolfers[];
它应该是:
private Golfer[] lGolfers;
并初始化为:
lGolfers = new Golfer[100];
(或您想要的任何尺寸)
更好的方法是使用ArrayList:
private ArrayList<Golfer> lGolfers = new ArrayList<Golfer>();
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