java - getWritableDatabase 函数导致错误

Question

我正在创建一个名为 Mycontacts 的应用程序。这与 youtube 上的视频相同( https://www.youtube.com/watch?v=38DOncHIazs )。

但是这个getWritableDatabase()导致了错误

Non-static method 'getWritableDatabase()' cannot be referenced from a static context

public class addcontacts extends AppCompactActivity
{ 

    EditText conname, conmobno, conemail;
    Context context = this;
    userDbHelper userdbhelp;
    SQLiteDatabase sqLiteDatabase;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.addcontacts);
        conname = (EditText) findViewById(R.id.Name);
        conmobno = (EditText) findViewById(R.id.Contno);
        conemail = (EditText) findViewById(R.id.Eid);
    }

    public void addContest(View view)  {
        String name = conname.getText().toString();
        String mobno = conmobno.getText().toString();
        String conem = conemail.getText().toString();
        userdbhelp = new userDbHelper(context);
        sqLiteDatabase = userDbHelper.getWritableDatabase();
        userdbhelp.addinformation(name,mobno,conem, sqLiteDatabase);
        Toast.makeText(getBaseContext(),"data saved",Toast.LENGTH_SHORT).show();
        userdbhelp.close();
    }
}

Answer 1

改变

userdbhelp = new userDbHelper(context);
sqLiteDatabase = userDbHelper.getWritableDatabase();

至

userdbhelp = new userDbHelper(context);
sqLiteDatabase = userdbhelp.getWritableDatabase();

您需要在实例 userdbhelp 上调用该方法，而不是在类 userDbHelper 上调用该方法。