java - 安卓教程错误

Question

我从 Wei-Meng Lee 的“开始 Android 应用程序开发”中借用了以下代码:

import android.content.Context;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

public class DBAdapter {

    private static final String TAG = "DBAdapter";
    private static final String DATABASE_NAME = "MyDB";
    private static final int DATABASE_VERSION = 1;
    private static final String DATABASE_CREATE =
            "create table contacts (_id integer primary key autoincrement, "
                    + "name text not null, email text not null);";
    private final Context context;
    private DatabaseHelper DBHelper;
    private SQLiteDatabase db;
    public DBAdapter (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);
        }
    }
}

还有更多，但我正在努力简化。

我收到以下错误:

Description Resource Path Location Type

Syntax error on token ")", { expected after this token DBAdapter.java

在 onUpgrade 结束

Syntax error, insert "}" to complete ClassBody DBAdapter.java

Syntax error, insert "}" to complete ClassBody DBAdapter.java

在 onCreate 结束时

我是 Android 应用的新手，有人可以帮助我理解这些消息吗？

这是 Eclipse 显示的内容:

Answer 1

这些是来自编译器的消息，告诉您大括号 {} 和/或圆括号 () 在文件中不平衡。如果您复制/粘贴了此代码，请确保您没有遗漏末尾的大括号或类似内容。您发布的代码看起来很平衡，因此它必须在文件中更靠后的位置。

HTH