Android Studio如何正确地将listview项目插入sqlite数据库

Question

我试图将我的 listview 项目存储到我的 sql 数据库中，这段代码不起作用：它只是一直运行，但没有在数据库中存储任何内容。对如何将列表视图插入 sql 数据库有任何帮助吗？

这是我尝试插入列表视图项的代码部分

for(int i=0;i<=myAdapter.myItems.size();i++){
    String name=tabl.getText().toString();
    String answer=myAdapter.getItem(i).toString();
    mHelper.insertData(name,answer);
    //mHelper is the variable name for my DBhandler class
}

这是我的 DBhandler 类

public class DBHandler extends SQLiteOpenHelper {
    public static final String DB_NAME = "quiz.db";
    public static final int DB_VERSION = 2;
    public static final String TABLE = "user";
    public static final String COL_TASK_TITLE = "title";
    public static final String ID = "id";
    public static final String COL_ANS="answer";
    public DBHandler(Context context) {
        super(context, DB_NAME, null, DB_VERSION);
        SQLiteDatabase db=getWritableDatabase();
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        String createtable="CREATE TABLE " + TABLE + " ( "+ ID +" INTEGER PRIMARY KEY AUTOINCREMENT, "+ COL_TASK_TITLE+ "TEXT NOT NULL,"+ COL_ANS+"TEXT NOT NULL);";
        db.execSQL(createtable);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("DROP TABLE IF EXISTS " + TABLE);
        onCreate(db);
    }
    public boolean insertData(String name,String quiz){
        SQLiteDatabase db=this.getWritableDatabase();
        ContentValues contex=new ContentValues();
        contex.put(COL_TASK_TITLE,quiz);
        contex.put(COL_ANS,name);
        long result=db.insert(TABLE,null,contex);
        if(result==-1)
        {
            return false;
        }else{
            return true;
        }
    }
}

Answer 1

public class DBHandler extends SQLiteOpenHelper {
    public static final String DB_NAME = "quiz.db";
    public static final int DB_VERSION = 1;
    public static final String TABLE = "user";
    public static final String COL_TASK_TITLE = "title";
    public static final String ID = "id";
    public static final String COL_ANS = "answer";

    public DBHandler(Context context) {
        super(context, DB_NAME, null, DB_VERSION);

    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        String createtable="CREATE TABLE " + TABLE + " ( "+ ID +" INTEGER PRIMARY KEY AUTOINCREMENT, "+ COL_TASK_TITLE+ " TEXT NOT NULL,"+ COL_ANS+" TEXT NOT NULL)";
        db.execSQL(createtable);
        Log.i("Create",createtable + " Created");
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("DROP TABLE IF EXISTS " + TABLE);
        onCreate(db);
    }

    public boolean insertData(String name, String quiz) {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues contex = new ContentValues();
        contex.put(COL_TASK_TITLE, quiz);
        contex.put(COL_ANS, name);
        long result = db.insert(TABLE, null, contex);
        Log.i("Inserted ", "Done");
        if (result == -1) {
            return false;
        } else {
            return true;
        }
    }


}

希望这对您有所帮助，您只需避免在创建表 SQL 语句中连接。只需卸载之前的应用即可。

Answer 2

    String createtable="CREATE TABLE " + TABLE + " ( "+ ID +" INTEGER PRIMARY KEY AUTOINCREMENT, "+ COL_TASK_TITLE+ " TEXT NOT NULL,"+ COL_ANS+" TEXT NOT NULL)";

在 TEXT NOT NULL 之前保留一些空格，它将列名和数据类型连接起来。