Java 在整个活动中使用Const来存储值？

我有4个类：Const、Users、FacebookProfile和Test类。我已经设法从facebook上获得了生物数据。我想将biodata保存到Const，这样在测试类上我就可以通过Const.getName（）来吐司fname

下一个类是用于保存数据的Const

public final class Const  {

Users users;

public Users getUsers(){
    return users;
}

public void setUsers(Users users){

    this.users = users;
}


private Const() {
    init();
}

public static Const getInstance() {
    return ConstHolder.INSTANCE;
}

private void init() {
    this.getUsers();
}

private static class ConstHolder {
    private static final Const INSTANCE = new Const();
}



}

---

我发现我的问答题的答案很简单，通过你的应用程序一直使用Const

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button button , button1;


        button1 = (Button)findViewById(R.id.buttondata);
        button1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String name = "Alex";
                String lname = "Boey";
                Users users = new Users();
                users.setFname(name);
                users.setLname(lname);
                Const.getInstance().setUsers(users);
                Toast.makeText(getApplicationContext(),"Data saved", Toast.LENGTH_LONG).show();

            }
        });


        button = (Button) findViewById(R.id.buttonb);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                try {
                    Toast.makeText(getApplicationContext() ,Const.getInstance().getUsers().getFname().toString() + Const.getInstance().getUsers().getLname(),Toast.LENGTH_LONG).show();

                }catch (Exception e){
                    Toast.makeText(getApplicationContext() , "Nothing found in the Const" , Toast.LENGTH_LONG).show();
                }

            }
        });



    }


}

---

“我如何将它保存在const上以访问应用程序的任何地方”-在这种情况下，我会认为它是坏的实践，但是你可以检查。我会投票反对使用单身汉。相反，我会传递

Const

的引用，或者考虑将数据库添加到项目中。

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button button , button1;


        button1 = (Button)findViewById(R.id.buttondata);
        button1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String name = "Alex";
                String lname = "Boey";
                Users users = new Users();
                users.setFname(name);
                users.setLname(lname);
                Const.getInstance().setUsers(users);
                Toast.makeText(getApplicationContext(),"Data saved", Toast.LENGTH_LONG).show();

            }
        });


        button = (Button) findViewById(R.id.buttonb);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                try {
                    Toast.makeText(getApplicationContext() ,Const.getInstance().getUsers().getFname().toString() + Const.getInstance().getUsers().getLname(),Toast.LENGTH_LONG).show();

                }catch (Exception e){
                    Toast.makeText(getApplicationContext() , "Nothing found in the Const" , Toast.LENGTH_LONG).show();
                }

            }
        });



    }


}