android - Sqlite 列 id 不是唯一的

Question

下面是我的代码，我只是想将我插入到 sqlite 数据库中的数据显示到 TextView 中，但是我有这个错误，指出 id 不是唯一的。

    package com.example.sqlitetest;

import android.app.Activity;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.widget.Button;
import android.widget.TextView;

public class Main extends Activity {

    TextView scrName, fName;
    Button go;
    SQLiteDatabase db;
    String screenName, fullName;
    Cursor cursor;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        db = openOrCreateDatabase("MyDataBase", MODE_PRIVATE, null);
        db.execSQL("CREATE TABLE if not exists MyTable(ScreenName Varchar, FullName Varchar, id int(3) PRIMARY KEY);");
        db.execSQL("Insert into MyTable VALUES('joff', 'tiquez', 1);");
        cursor = db.rawQuery("Select * from MyTable", null);
        cursor.moveToFirst();

        scrName = (TextView) findViewById(R.id.scrName);
        fName = (TextView) findViewById(R.id.fName);

        while(cursor.isAfterLast() == false){
            //retrieving the data from sqlite (im not sure if im doing it right)
            String screenname = cursor.getString(cursor.getColumnIndex("ScreenName"));
            String fullname = cursor.getString(cursor.getColumnIndex("FullName"));

            //this are the textview
            scrName.setText(screenname);
            fName.setText(fullname);

            cursor.moveToNext();
        }
        db.close();
    }
}

这是我的整个 Java 代码。谢谢:)

Answer 1

嗯，我认为这个项目在您第一次运行时运行良好。当您第二次运行它时，它会出错，因为 id 是您的 primary key 并且 id 为 1 的行已经插入到您的数据库中。

要消除错误:

1) uninstall the app and run it again   
2) Don't make id as primary key   
3) Catch the exception and handle it yourself