Question

我正遇到我的代码的问题，当我尝试使用insert（tablename，null，contenValues）函数在数据库中插入信息时，它返回-1。这是我的代码

    public void addItem(View view) {
        String t1 = nameEt.getText().toString();
        String t2 = priceEt.getText().toString();

        if(t1.isEmpty() || t2.isEmpty()) {
            Functions.message(this, "Enter both fields");
        }
        else {
            long id = helper.insertData(t1, t2);
            if (id<=0) {
                Functions.message(this, "Unsuccessful");
            }
            else {
                Functions.message(this, "Inserted!");
            }
        }

   class myDataBaseAdapter {
                private myDataBaseHelper myhelper;
                myDataBaseAdapter(Context context) {
                    myhelper = new myDataBaseHelper(context);
                }

                long insertData(String name, String price) {

                    long id;

                    SQLiteDatabase db = myhelper.getWritableDatabase();
                    ContentValues contentValues = new ContentValues();
                    contentValues.put(myDataBaseHelper.NAME, name);
                    contentValues.put(myDataBaseHelper.PRICE, price);
                    id = db.insert(myDataBaseHelper.TABLE_NAME, null, contentValues);
                    return id;
                }

                static class myDataBaseHelper extends SQLiteOpenHelper {

                    private static final String DATABASE_NAME = "myDataBase";
                    private static final String TABLE_NAME = "myTable";
                    private static final int DATABASE_VERSION = 1;
                    private static final String UID = "_id";
                    private static final String NAME = "Name";
                    private static final String PRICE = "Price";
                    private static final String CREATE_TABLE = "CREATE TABLE "+DATABASE_NAME+" ("+UID+" INTEGER PRIMARY KEY AUTOINCREMENT, "+NAME+" VARCHAR(255), "+PRICE+" VARCHAR(255));";
                    private static final String DROP_TABLE = "DROP TABLE IF EXISTS "+TABLE_NAME;
                    private Context context;

                    myDataBaseHelper(Context context) {
                        super(context, DATABASE_NAME, null, DATABASE_VERSION);
                        this.context = context;
                        Functions.message(context, "constructor called");
                    }

                    @Override
                    public void onCreate(SQLiteDatabase db) {
                        try {
                            db.execSQL(CREATE_TABLE);
                            Functions.message(context, "onCreate called");
                        } catch (SQLException e) {
                            Functions.message(context, ""+e);
                        }
                    }

                    @Override
                    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
                        try {
                            db.execSQL(DROP_TABLE);
                            Functions.message(context, "onUpgrade called");
                            onCreate(db);
                        } catch (SQLException e) {
                            Functions.message(context, ""+e);
                        }
                    }
                }
            }

消息功能只是一个简单的祝酒消息，对我有帮助。如果这有任何区别，我正在使用android studio。我该如何纠正

Answer 1

在尝试在onCreate()上进行插入时，您的myDataBase创建一个名为myTable的表。更改

"CREATE TABLE "+DATABASE_NAME+"

到

"CREATE TABLE "+TABLE_NAME+"

您可以卸载应用程序以重新创建数据库。

在那里，请考虑删除所有这些catch (SQLException)块-如果SQL存在问题，它们将被隐藏。您希望尽早发现编程错误。

SQLite，dabase.insert（）返回-1

1 个答案: