java - 局部变量可能尚未初始化

Question

public class DatabaseHandler extends SQLiteOpenHelper {


// All Static variables
// Database Version
private static final int DATABASE_VERSION = 1;

// Database Name
private static final String DATABASE_NAME = "contextsManager";

// Locations table name
private static final String TABLE_LOCATIONLABLES = "locationLables";

// LOCATIONLABLES Table Columns names
private static final String KEY_LOCID = "loc_id";
private static final String KEY_LOCNAME = "loc_name";

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

// Creating Tables
@Override
public void onCreate(SQLiteDatabase db) {
    String TABLE_LOCATIONLABLES = "CREATE TABLE " + TABLE_LOCATIONLABLES + "("
            + KEY_LOCID + " INTEGER PRIMARY KEY," + KEY_LOCNAME + " TEXT,"
            +  ")";
    db.execSQL(TABLE_LOCATIONLABLES);   
}

这是说局部变量TABLE_LOCATIONLABLES可能尚未初始化？已经初始化了，怎么会出现这个错误呢？

Answer 1

问题出在你的代码本身

 // Creating Tables
    @Override
    public void onCreate(SQLiteDatabase db) {
        String TABLE_LOCATIONLABLES = "CREATE TABLE " + TABLE_LOCATIONLABLES + "("
                + KEY_LOCID + " INTEGER PRIMARY KEY," + KEY_LOCNAME + " TEXT,"
                +  ")";
        db.execSQL(TABLE_LOCATIONLABLES);   
    }

在 oncreate(db) 中，您再次声明了 TABLE_LOCATIONLABLES 并在同一行中使用它，这就是为什么您得到 Localvariable may not have beeninitialized

只需像这样重命名 oncreate(db) 中的字符串 TABLE_LOCATIONLABLES

    @Override
    public void onCreate(SQLiteDatabase db) {
        String mQuery = "CREATE TABLE " + TABLE_LOCATIONLABLES + "("
                + KEY_LOCID + " INTEGER PRIMARY KEY," + KEY_LOCNAME + " TEXT,"
                +  ")";
        db.execSQL(mQuery);   
    }