如何在安卓中创建多个用户注册和登录活动?

Question

我已经使用共享首选项在安卓中进行了注册和登录活动。用户能够成功注册和登录。但我的问题是，当新用户注册时，它会删除以前用户的注册详细信息。

这是我的注册页面：

public class Registration extends Activity implements 
View.OnClickListener 
{
SharedPreferences pref;
Editor editor;
TextView btn_registration , btn_formlogin;
EditText et_name, et_pass, et_email , et_phone ;
ImageView btn_upload ;
private static final int PICK_IMAGE_REQUEST = 0;
private Uri mImageUri;
SessionManager session;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_registration);

et_name = (EditText) findViewById(R.id.edt_Name);
et_pass = (EditText) findViewById(R.id.edt_userPassword);
et_email = (EditText) findViewById(R.id.edt_userEmail);
et_phone = (EditText) findViewById(R.id.edt_Phone);
btn_registration = (TextView) findViewById(R.id.btn_registration);
btn_formlogin = (TextView) findViewById(R.id.btn_formlogin);
btn_upload = (ImageView)findViewById(R.id.img_upload);
Map<String,String> values = new HashMap<String,String>();
AppCompatDelegate.setCompatVectorFromResourcesEnabled(true);
btn_upload.setOnClickListener(this);
SharedPreferences preference = 
PreferenceManager.getDefaultSharedPreferences(this);
final String mImageUri = preference.getString("image", null);
btn_upload.setImageResource(R.drawable.adduser);
// creating an shared Preference file for the information to be stored
// first argument is the name of file and second is the mode, 0 is 
private mode
pref = getSharedPreferences("USER_CREDENTIALS", 0);
// get editor to edit in file
editor = pref.edit();

// the tap of button we will fetch the information from four edittext
btn_registration.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick (View v) {

boolean validName = true;
boolean validPass = true;
boolean validPhone = true;
boolean validEmail = true;
String name = et_name.getText().toString();
String email = et_email.getText().toString();
String pass = et_pass.getText().toString();
String phone = et_phone.getText().toString();

if (isEmpty(et_name)) {
et_name.setError("Enter the Name");
validName = false;
}

if (isEmpty(et_pass)) {
et_pass.setError("Password can't be null");
validPass = false;
}
if (isEmail(et_email) == false) {
et_email.setError("Enter valid email");
validEmail = false;
}
if (isValidMobile(et_phone) == false) {
validPhone = false;
}

final String required_email= pref.getString("Email",null);
final String required_phone=pref.getString("Phone",null);
if(et_email.equals(required_email)){
validEmail = true;
}
else if(et_phone.equals(required_phone)){
validPhone = true;
}

if (validName && validPass && validPhone && validEmail){
// as now we have information in string. Lets stored them 
with the help of editor
editor.putString("Name" , name );
editor.putString("Email", email);
editor.putString("Password", pass);
editor.putString("Phone", phone);
editor.putString("image", String.valueOf(mImageUri));
editor.commit();   // commit the values
Toast.makeText(Registration.this, "Registration 
Successful", Toast.LENGTH_LONG).show();
session = new SessionManager(getApplicationContext());
session.createLoginSession(name, email, mImageUri);
// after saving the value open next activity
Intent ob = new Intent(Registration.this, 
DashBoard.class);
startActivity(ob);
}
else{
Toast.makeText(Registration.this, "Registration 
unsuccessful! Please retry.", Toast.LENGTH_LONG).show();
}
}
});

我只想知道如何使用共享首选项文件注册多个用户？

Answer 1

如果你有多个用户，最好使用数据库(sqlite)而不是共享的首选项。

Answer 2

在共享首选项中，如果要在设备中保存多个用户，则只能在对象中保存单个值，则可以使用房间数据库在设备中存储多个用户详细信息。共享首选项只能用于单个信息，或者如果要在共享首选项中存储多个值，则可以将 arrayList 存储在共享首选项中。

在共享首选项中保存数组列表：-

private static SharedPreferences mPrefs;
private static SharedPreferences.Editor mPrefsEditor;
public static Set<String> getCamEval(Context ctx) {
mPrefs = PreferenceManager.getDefaultSharedPreferences(ctx);
return mPrefs.getStringSet("sdk_camEval", null);
}
public static void setCamEval(Context ctx, ArrayList<String> value) {
mPrefs = PreferenceManager.getDefaultSharedPreferences(ctx);
mPrefsEditor = mPrefs.edit();
Set<String> set = new HashSet<>();
set.addAll(value);
mPrefsEditor.putStringSet("sdk_camEval", set);
mPrefsEditor.commit();
}