我在插入查询时遇到错误android.database.sqlite.SQLiteConstraintException：NOT NULL约束失败：contacts.id（代码1299）

Question

这是我的注册类的插入代码。我得到了：

  

（android.database.sqlite.SQLiteConstraintException：NOT NULL   约束失败：contacts.id（代码1299））

if (R.id.bRegister == v.getId()) {
    EditText uname = (EditText) findViewById(R.id.etUsername);
    EditText pass = (EditText) findViewById(R.id.etPasswprd);
    EditText email = (EditText) findViewById(R.id.etEmail);

    String unamestr = uname.getText().toString();
    String emailstr = email.getText().toString();
    String passstr = pass.getText().toString();

    Contact c = new Contact();

    c.setUname(unamestr);
    c.setEmail(emailstr);
    c.setPass(passstr);
    helper.insertContact(c);
    Toast temp = Toast.makeText(Register.this, "Register Done ", Toast.LENGTH_SHORT);
    temp.show();
}

编辑 insertContact是：

public void insertContact(Contact c) {
    db = this.getWritableDatabase();
    ContentValues values = new ContentValues();
    String query = " select *from contacts ";
    Cursor cursor = db.rawQuery(query, null);
    int count = cursor.getCount();
    values.put(COLUMN_UNAME, c.getUname());
    values.put(COLUMN_EMAIL, c.getEmail());
    values.put(COLUMN_PASS, c.getPass());
    db.insert(TABLE_NAME, null, values);
    db.close();
}