Java 如何从getter setter类获取数据？

我是android开发的初学者，我有一些问题，请帮助我。 我有两个屏幕登录，登录后，我在登录类中设置了用户id，我想在登录后如何获取中使用该用户id，当我使用get方法时，查找Null如何解决此问题。
这是我的登录代码`公共类LoginActivity extends FragmentActivity{

private EditText userName;
private EditText password;
private TextView forgotPassword;
private TextView backToHome;
private Button login;
private CallbackManager callbackManager;
private ReferanceWapper referanceWapper;
private LoginBean loginBean;
Context context;
String regid;
GoogleCloudMessaging gcm;
String SENDER_ID = "918285686540";

public static final String PROPERTY_REG_ID = "registration_id";
private static final String PROPERTY_APP_VERSION = "appVersion";
private final static int PLAY_SERVICES_RESOLUTION_REQUEST = 9000;
static final String TAG = "GCM";


@Override
protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    setContentView(R.layout.activity_login);
    Utility.setStatusBarColor(this, R.color.tranparentColor);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
    Typeface tf = Typeface.createFromAsset(getAssets(), "fonts/OpenSans_Regular.ttf");
    setupUI(findViewById(R.id.parentEdit));

    userName = (EditText) findViewById(R.id.userName);
    userName.setTypeface(tf);
    userName.setFocusable(false);
    userName.setOnTouchListener(new View.OnTouchListener() {
        public boolean onTouch(View view, MotionEvent paramMotionEvent) {
            userName.setFocusableInTouchMode(true);
            Utility.hideSoftKeyboard(LoginActivity.this);
            return false;
        }
    });


    password = (EditText) findViewById(R.id.passwordEText);
    password.setTypeface(tf);
    password.setFocusable(false);
    password.setOnTouchListener(new View.OnTouchListener() {
        public boolean onTouch(View paramView, MotionEvent paramMotionEvent) {
            password.setFocusableInTouchMode(true);
            Utility.hideSoftKeyboard(LoginActivity.this);
            return false;
        }
    });


    forgotPassword = (TextView) findViewById(R.id.forgotPassword);
    forgotPassword.setTypeface(tf);
    forgotPassword.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent intent = new Intent(getApplicationContext(),ForgotPasswordActivity.class);
            startActivity(intent);
        }
    });

    backToHome = (TextView) findViewById(R.id.fromLogToHome);
    backToHome.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            onBackPressed();
        }
    });
    login = (Button) findViewById(R.id.loginBtn);

    login.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            doLoginTask();
            //  Intent intent = new Intent(getApplicationContext(), AfterLoginActivity.class);
            //  startActivity(intent);

        }
    });
}


private void doLoginTask() {

    String strEmail = userName.getText().toString();
    String strPassword = password.getText().toString();
    if (strEmail.length() == 0) {
        userName.setError("Email Not Valid");
    } else if (!Utility.isEmailValid(strEmail.trim())) {
        userName.setError("Email Not Valid");
    } else if (strPassword.length() == 0) {
        password.setError(getString(R.string.password_empty));
    } else {

        JSONObject jsonObject = null;
        try {
            jsonObject = new JSONObject();
            jsonObject.putOpt(Constants.USER_NAME, strEmail);
            jsonObject.putOpt(Constants.USER_PASSWORD, strPassword);
            jsonObject.putOpt(Constants.DEVICE_TOKEN, "11");
            jsonObject.putOpt(Constants.MAC_ADDRESS, "111");
            jsonObject.putOpt(Constants.GPS_LATITUDE, "1111");
            jsonObject.putOpt(Constants.GPS_LONGITUDE, "11111");
        } catch (JSONException e) {
            e.printStackTrace();
        }
        final ProgressDialog pDialog = new ProgressDialog(this);
        pDialog.setMessage("Loading...");
        pDialog.show();

        CustomJSONObjectRequest jsonObjectRequest = new CustomJSONObjectRequest(Request.Method.POST, Constants.USER_LOGIN_URL, jsonObject, new Response.Listener<JSONObject>() {
            @Override
            public void onResponse(JSONObject response) {
                pDialog.dismiss();
                Log.e("LoginPage", "OnResponse =" + response.toString());
                getLogin(response);
                //LoginBean lb = new LoginBean();
                //Toast.makeText(getApplicationContext(),lb.getFull_name()+"Login Successfuly",Toast.LENGTH_LONG).show();
                Intent intent = new Intent(getApplicationContext(),AfterLoginActivity.class);
                startActivity(intent);
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                Toast.makeText(getApplicationContext(),"Something, wrong please try again",Toast.LENGTH_LONG).show();
                pDialog.dismiss();

            }
        });
        jsonObjectRequest.setRetryPolicy(new DefaultRetryPolicy(
                5000,
                DefaultRetryPolicy.DEFAULT_MAX_RETRIES,
                DefaultRetryPolicy.DEFAULT_BACKOFF_MULT));
        Log.e("LoginPage", "Url= " + Constants.USER_LOGIN_URL + " PostObject = " + jsonObject.toString());
        AppController.getInstance().addToRequestQueue(jsonObjectRequest);
    }

}

public void getLogin(JSONObject response) {
    LoginBean loginBean = new LoginBean();
    if (response != null){
        try {
            JSONObject jsonObject = response.getJSONObject("data");
            loginBean.setUser_id(jsonObject.getString("user_id"));
            loginBean.setFull_name(jsonObject.getString("full_name"));
            loginBean.setDisplay_name(jsonObject.getString("display_name"));
            loginBean.setUser_image(jsonObject.getString("user_image"));
            loginBean.setGender(jsonObject.getString("gender"));
            loginBean.setAuthorization_key(jsonObject.getString("authorization_key"));

        } catch (JSONException e) {
            e.printStackTrace();
        }
    }
    Toast.makeText(getApplicationContext(),"User id is "+loginBean.getUser_id(),Toast.LENGTH_LONG).show();
}
public void onBackPressed() {
    finish();
}

public void setupUI(View view) {

    //Set up touch listener for non-text box views to hide keyboard.
    if (!(view instanceof EditText)) {

        view.setOnTouchListener(new View.OnTouchListener() {

            public boolean onTouch(View v, MotionEvent event) {
                Utility.hideSoftKeyboard(LoginActivity.this);
                return false;
            }

        });
    }


}

private ImageView partyIcon;
private ImageView dealIcon;
private ImageView deliveryIcon;
private TextView  txtParty;
private TextView  txtDeals;
private TextView  txtDelivery;
boolean doubleBackToExitPressedOnce = false;
int backButtonCount = 0;

@Override
protected void onCreate(Bundle savedInstanceState) {
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_after_login);
    Utility.setStatusBarColor(this, R.color.splash_status_color);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);

    partyIcon = (ImageView)findViewById(R.id.party_Icon);
    dealIcon = (ImageView)findViewById(R.id.deals_Icon);
    deliveryIcon = (ImageView)findViewById(R.id.delivery_Icon);

    partyIcon.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent intent = new Intent(getApplication(), BookPartyActivity.class);
            startActivity(intent);

        }
    });
    dealIcon.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent intent = new Intent(getApplication(), DealsActivity.class);
            startActivity(intent);

        }
    });
    deliveryIcon.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            LoginBean loginBean = new LoginBean();
            Toast.makeText(getBaseContext(),"Auth"+loginBean.getUser_id(),Toast.LENGTH_LONG).show();
            Intent intent = new Intent(getApplicationContext(),MyAuction.class);
            startActivity(intent);
        }
    });

}
/*
public void onBackPressed()
{


    if (doubleBackToExitPressedOnce)
    {
        Intent intent = new Intent(getApplicationContext(), MainActivity.class);
        intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        startActivity(intent);
        finish();
    }
    doubleBackToExitPressedOnce = true;
    Toast.makeText(this, "you have logged in ,plz enjoy the party", Toast.LENGTH_LONG).show();
    new Handler().postDelayed(new Runnable()
    {
        public void run()
        {
           doubleBackToExitPressedOnce = false;
        }
    }
            , 2000L);
}*/
@Override
public void onBackPressed()
{

    if(backButtonCount >= 1)
    {
        Intent intent = new Intent(Intent.ACTION_MAIN);
        intent.addCategory(Intent.CATEGORY_HOME);
        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        startActivity(intent);
    }
    else
    {
        Toast.makeText(this, "Press the back button once again to close the application.", Toast.LENGTH_SHORT).show();
        backButtonCount++;
    }
}

}`

这是LoginBean `公共类LoginBean{ 私有字符串用户标识； 私有字符串全名； 私有字符串显示名称； 私有字符串用户图像； 私人字符串性别； 私有字符串授权密钥

public void setUser_id(String user_id) {
    this.user_id = user_id;
}
public String getUser_id() {
    return user_id;
}


public void setFull_name(String full_name) {
    this.full_name = full_name;
}
public String getFull_name() {
    return full_name;
}


public void setDisplay_name(String display_name) {
    this.display_name = display_name;
}
public String getDisplay_name() {
    return display_name;
}


public void setUser_image(String user_image) {
    this.user_image = user_image;
}
public String getUser_image() {
    return user_image;
}


public void setGender(String gender) {
    this.gender = gender;
}
public String getGender() {
    return gender;
}


public void setAuthorization_key(String authorization_key) {
    this.authorization_key = authorization_key;
}
public String getAuthorization_key() {
    return authorization_key;
}

---

}`

您可以编写并应用下面提到的步骤（请忽略任何语法错误，我给您简单的逻辑步骤）

步骤1-制作一个全局应用程序级loginObject setter和getter，如下所示。确保在清单中定义应用程序类，就像为您的LoginActivity定义应用程序类一样

公共类ApplicationClass扩展了应用程序{

private LoginBean loginObject;



public void setLoginBean(LoginBean object) {

    this.loginObject = object;
}

public LoginBean getName() {

   return this.loginObject

}

}

步骤2：在LoginActivity中获取ApplicationClass对象引用的实例，以设置此全局loginObject

e、 g.在当前Loginactivity中设置Login对象，如下所示

私有应用程序类appObject

@凌驾 创建时受保护的void（Bundle savedInstanceState）{

}

步骤3：在任何其他活动中获取ApplicationClass对象引用的实例获取需要访问此登录数据的全局loginObject

e、 g.像这样在otherActivity中使用getLogin对象

私有应用程序类appObject

@凌驾 创建时受保护的void（Bundle savedInstanceState）{

---

}

成功登录后，将userId放入共享首选项中，这样您就可以随时随地使用。这是一种非常简单的方法，可以保存并进入完整的应用程序。这是一个非常简单的Java问题。请参阅以获得更清晰的理解。@SuhasB登录成功后，我想单击deliveryBTN和message toast，因为用户可以这样做。使用相同的方法。这对我非常有帮助，非常感谢Suhas。

private LoginBean loginObject;



public void setLoginBean(LoginBean object) {

    this.loginObject = object;
}

public LoginBean getName() {

   return this.loginObject

}

......

appObject = (ApplicationClass) LoginActivity.this.getApplication();

.......

appObject.setLoginBean(loginObject)

......

appObject = (ApplicationClass) LoginActivity.this.getApplication();

.......

LoginBean loginObject = appObject.getLoginBean();