java.lang.NullPointerException：尝试在空对象引用上调用虚拟方法

Question

我的代码中出现以下错误可能是我遗漏了一些东西，我有另一个具有相同类型的代码并且工作正常：java.lang.NullPointerException: 尝试调用虚拟方法'long app.akexorcist.bluetoothspp.DatabaseHelper.insertData(java.lang.String, java.lang.String, java.lang.String, java.lang.String, java.lang .String, java.lang.String, java.lang.String, java.lang.String, java.lang.String, java.lang.String, java.lang.String, java.lang.String)' 在一个空对象上参考以下是一些代码：谢谢public void postDataToSQLite() { SharedPreferences sharedpreferences = getSharedPreferences(LoginActivity.MyPREFERENCES, Context.MODE_PRIVATE); SharedPreferences.Editor 编辑器 = sharedpreferences.edit();    SharedPreferences vehiclesharedpreferences = getSharedPreferences(VehicleEntryActivity.MyVehicle, Context.MODE_PRIVATE);    SharedPreferences.Editor vehicle_editor = sharedpreferences.edit();    String name = txtName.getText().toString();    String surname = txtSurname.getText().toString();    String idno = txtIDNo.getText().toString();    String birth = txtDateBirth.getText().toString();    String username = sharedpreferences.getString(Name, "");    editor.apply();    String make = vehiclesharedpreferences.getString(Make, "");    String colour = vehiclesharedpreferences.getString(Colour, "");    String expiry = vehiclesharedpreferences.getString(Expiry, "");    String regno = vehiclesharedpreferences.getString(RegNo, "");    String date = vehiclesharedpreferences.getString(DateTime, "");    String loc = vehiclesharedpreferences.getString(GPS, "");    vehicle_editor.apply();    String event = "Entry";    if(name.isEmpty() || surname.isEmpty() || idno.isEmpty() || birth.isEmpty())    {        Toast.makeText(this, "Please scan drivers licence", Toast.LENGTH_SHORT).show();    }    else    {        long id = helper.insertData(make,colour,expiry,regno,date,loc,name,surname,idno,birth,event,username);        Intent intent = null;        if(id<=0)        {            Message.message(getApplicationContext(),"Failed... Please Check Data");        }

Answer 1

您的变量“助手”似乎为空或未启用。

你怎么称呼你的助手？