Question

-1始终返回public class database_class extends SQLiteOpenHelper { public static final String database_name = "signup_db"; public static final String table_name = "signup"; public static final String column_1 = "FIRST_NAME"; public static final String column_2 = "SECOND_NAME"; public static final String column_3 = "EMAIL"; public static final String column_4 = "PASSWORD"; public static final String column_5 = "c_password"; public database_class(Context context){ super(context,database_name , null, 1); //Toast.makeText(context, "Class called ", Toast.LENGTH_SHORT).show(); } @Override public void onCreate(SQLiteDatabase db) { db.execSQL("create table" + table_name + "(ID INTEGER PRIMARY KEY AUTOINCREMENT , FIRST_NAME TEXT , SECOND_NAME TEXT , EMAIL TEXT , PASSWORD TEXT)"); } @Override public void onUpgrade(SQLiteDatabase db, int i, int i1) { db.execSQL("DROP TABLE IF EXISTS" + table_name); onCreate(db); } public boolean insertData(String first_name, String second_name, String email, String password){ SQLiteDatabase db = this.getWritableDatabase(); ContentValues contentValues = new ContentValues(); contentValues.put(column_1,first_name); contentValues.put(column_2,second_name); contentValues.put(column_3,email); contentValues.put(column_4,password); long result = db.insert(table_name,null,contentValues); if (result == -1) return false; else return true; } }，并且不会在数据库中插入值。

请你帮我弄清楚我做错了什么？

database_class.java：

fn = editText1.getText().toString();
ln = editText2.getText().toString();
em = editText3.getText().toString();
pass = editText4.getText().toString();
cpass = editText5.getText().toString();

if (1 == 1) {
    //boolean isInserted =  mydb.insertData(signup_values[0].toString(),signup_values[1].toString(),signup_values[2].toString(),signup_values[3].toString());
    boolean isInserted =  mydb.insertData(fn,ln,em,pass);
    if(isInserted == true) {
        Toast.makeText(MainActivity.this, "Data Inserted", Toast.LENGTH_SHORT).show();
    }
    else
        Toast.makeText(MainActivity.this, "Data not Inserted", Toast.LENGTH_SHORT).show();
}
else
    Toast.makeText(MainActivity.this, "Password Mismatch", Toast.LENGTH_SHORT).show();

MainActivity Code：

{{1}}

Answer 1

我认为创建数据库时出错。这样，create表将失败，然后insert也将失败（因为表未正确创建）。

代码的其他部分似乎没问题......

此行将生成以下字符串：

db.execSQL("create table" + table_name + "(ID INTEGER PRIMARY KEY AUTOINCREMENT , FIRST_NAME TEXT , SECOND_NAME TEXT , EMAIL TEXT , PASSWORD TEXT)");

结果：

create tablesignup(ID INTEGER PRIMARY KEY AUTOINCREMENT , FIRST_NAME TEXT , SECOND_NAME TEXT , EMAIL TEXT , PASSWORD TEXT)

这不是有效的SQL命令。因此，尝试添加一些空格，如：

db.execSQL("create table " + table_name + " ( ID INTEGER PRIMARY KEY AUTOINCREMENT, FIRST_NAME TEXT, SECOND_NAME TEXT, EMAIL TEXT, PASSWORD TEXT )");

错误2

由于同样的错误，您的onUpgrade()也无法正常工作：

db.execSQL("DROP TABLE IF EXISTS" + table_name);

需要添加一些空格，例如：

db.execSQL("DROP TABLE IF EXISTS " + table_name);

<强>最后

我测试了你的代码并且运行正常。也许，之前发生过一些错误，“重新安装”数据库会很好。

你怎么做：

取消安装/安装您的应用
更新您的数据库版本以强制onUpgrade()。只需：super(context, database_name , null, 2);

onCreate()

ContentValues Insert总是返回-1

1 个答案: