Java 如何在导航抽屉的标题中显示用户的登录信息？

我正在开发一个应用程序，在该应用程序中，用户将在登录后通过提供用户名和电子邮件登录。一个页面将打开导航抽屉，然后我想在导航抽屉的标题中显示用户名和电子邮件。我尝试过很多方法，比如从edittext获取文本并将其显示到textview中，但没有任何效果，我不知道如何实现这一点

下面是文件

Navigation activity:
package com.example.hp.another;


import android.support.annotation.NonNull;
import android.support.design.widget.NavigationView;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.MenuItem;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;

public class NavigationActivity extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener {


    private DrawerLayout mdrawerlayout;
    private ActionBarDrawerToggle mtoggie;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_navigation);
        mdrawerlayout=(DrawerLayout) findViewById(R.id.drawer);
        mtoggie= new ActionBarDrawerToggle(this, mdrawerlayout, R.string.Open, R.string.Close);
        mdrawerlayout.addDrawerListener(mtoggie);
        mtoggie.syncState();
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);



    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        if (mtoggie.onOptionsItemSelected(item)){
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    @Override
    public boolean onNavigationItemSelected(@NonNull MenuItem item) {
        return false;
    }
}

header.xml
loginactivity.xml
首先使用以下代码访问标题文本视图

        View nav = navigationView.getHeaderView(0);
        TextView Username= (ImageView)nav.findViewById(R.id.Username);
        TextView Email= (ImageView)nav.findViewById(R.id.Email);

登录后，在SharedReferences中保存用户名和电子邮件，并将值设置为这些文本视图

每当我们在SharedReference中存储或检索数据时，我们都需要提交特定的用途

private SharedPreferences sharedPref;
private static String PREF_STRING = "pref_value";

  // method to store value in sharedPreferences
 public void login(String username_params, String email_params)
 {
   // initialize the sharePreferences
   sharedPref = getApplicationContext().getSharedPreferences(PREF_STRING,0);
   // use the editor to save the data
   SharedPreferences.Editor editor = sharedPref.edit();
   // add data to sharedPreferences using put() method

   editor.putString("username",username_params);
   editor.putString("email",email_params);

   // only this won't save your data to preferences, we need to commit this 
   transaction
   editor.commit(); // only after commit() data is saved in sharedPreferences
 }

现在，在将数据保存到首选项中后，我们可以从应用程序的任何部分访问该值

  public void getDataFromPrefernces()
  {
      // initialize the sharePreferences
      SharedPreferences prefefnces = 
      getApplicationContext().getSharedPreferences(PREF_STRING,0);
      // use the editor to retrieve the data
      SharedPreferences.Editor editor = prefefnces.edit();

      // here we save the sharedpreference values to string variables
      String username = prefefnces.getString("username",""); // make sure 
      you donot mismatch the name of the key/ it must be same with that you 
      stored
      String email = prefefnces.getString("email",""); 

      // again to get data we need to commit()
      editor.commit();

      // you can use these values from string variables wherever you need
   }

我在导航活动中进行了此更改。它不起作用SharedReferences sp=GetSharedReferences（“键”，0）；SharedReferences.Editor SharedEdit=sp.edit（）；putString（“用户名”，UserName.getText（）.toString（））；shareditr.putString（“Email”，Email.getText（）.toString（））；SharedReferences SharedReferences=GetSharedReferences（“键”，0）；字符串username=SharedReferences.getString（“用户名”，“用户名”）；String useremail=sharedPreferences.getString（“email”，”）；您尚未输入首选项值SharedReferences sp=GetSharedReferences（“键”，0）；SharedReferences.Editor SharedEdit=sp.edit（）；putString（“用户名”，UserName.getText（）.toString（））；shareditr.putString（“Email”，Email.getText（）.toString（））；提交（）；SharedReferences SharedReferences=GetSharedReferences（“键”，0）；SharedReferences.Editor Editor=SharedReferences.edit（）；字符串username=SharedReferences.getString（“username”，”）；String useremail=sharedPreferences.getString（“email”，”）；editor.commit（）；我认为我没有正确使用共享偏好方法，因为我不知道如何使用它。