我有一个名为LoginFragment的片段，用户可以通过单击“注册”按钮第一次注册。单击此按钮后，将打开一个名为RegisterFragment的新片段，用户可以选择并输入要注册的新用户名和密码。当我运行应用程序并输入注册下的字段并选择确定时，它会在吐司中显示“保存的信息”，就像它应该的那样。但是当我尝试使用我注册的用户名和密码登录时，应用程序无法识别信息并显示吐司“请检查条目并再试一次”，只有在用户名已存在或密码不正确时才会显示，在我的情况下并非如此。
SharedPreferences不保存用户名和密码值，因为我正在使用两个不同的片段吗？任何帮助将不胜感激！
RegisterFragment.java
public class RegisterFragment extends Fragment {
Button register_btn;
EditText username_signup_ET, password_signup_ET;
private String KEY_UID = "uid";
private String KEY_PASSWORD = "pwd";
private final String PREFER_NAME = "Registry";
private SharedPreferences sharedPreferences;
private SharedPreferences.Editor editor;
String username;
//LoginDataBaseAdapter loginDataBaseAdapter;
Context context;
public void myAlertDialog(){
context = getActivity();
}
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState){
View v = inflater.inflate(R.layout.register_fragment_layout, container, false);
sharedPreferences = getActivity().getSharedPreferences("loginPrefs", Context.MODE_PRIVATE);;
editor = sharedPreferences.edit();
username_signup_ET = (EditText)v.findViewById(R.id.username_signup_ET);
password_signup_ET = (EditText)v.findViewById(R.id.password_signup_ET);
register_btn = (Button)v.findViewById(R.id.register_btn);
register_btn.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
String userName = username_signup_ET.getText().toString();
String password = password_signup_ET.getText().toString();
if(userName.equals("")||password.equals(""))
{
Toast.makeText(getActivity(), "Please Enter Values in all Fields!", Toast.LENGTH_SHORT).show();
}
else{
register();
launchLogin();
}
}
});
return v;
}
//launch login activity
public void launchLogin(){
FragmentManager FM = getFragmentManager();
FragmentTransaction FT = FM.beginTransaction();
LoginFragment LG = new LoginFragment();
FT.addToBackStack("LG");
FT.replace(R.id.fragment_one_id, LG);
FT.commit();
}
// register your account
private void register() {
// prefix the keys with the user name
editor.putString("userName" + "_" + KEY_UID, username_signup_ET.getText()
.toString());
editor.putString("password" + "_" + KEY_PASSWORD, password_signup_ET.getText()
.toString());
//editor.commit(); // commit the values
editor.apply();
Toast.makeText(getActivity(), "Saved Info!", Toast.LENGTH_SHORT).show();
}// end of register
}
LoginFragment.java
public class LoginFragment extends Fragment {
Button login_btn, register_btn;
EditText username_ET, password_ET;
private String KEY_UID = "uid";
private String KEY_PASSWORD = "pwd";
private final String PREFER_NAME = "Registry";
private SharedPreferences sharedPreferences;
private SharedPreferences.Editor editor;
String username;
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState){
super.onCreateView(inflater, container, savedInstanceState);
View v = inflater.inflate(R.layout.login_fragment_layout, container, false);
sharedPreferences = getActivity().getSharedPreferences("loginPrefs", Context.MODE_PRIVATE);
editor = sharedPreferences.edit();
username_ET = (EditText)v.findViewById(R.id.username_ET);
password_ET = (EditText)v.findViewById(R.id.password_ET);
login_btn = (Button)v.findViewById(R.id.login_btn);
register_btn = (Button)v.findViewById(R.id.register_btn);
login_btn.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
// initialize username
username = username_ET.getText().toString();
boolean valid = isValid();
if (valid) {
String text = getResources().getString(R.string.logging_in_str);
Toast.makeText(getActivity().getApplicationContext(), text,
Toast.LENGTH_SHORT).show();
if (!userExists() | !(passwordCorrect())) {
text = getResources().getString(
R.string.error_username_str);
Toast.makeText(getActivity().getApplicationContext(), text,
Toast.LENGTH_SHORT).show();
} else {
Intent i = new Intent(getActivity(), DiaryActivity.class);
startActivity(i);
}
}
//sharedPreferences = getActivity().getSharedPreferences("loginPrefs", Context.MODE_PRIVATE);
//get username and password from EditText
String userName = username_ET.getText().toString();
String password = password_ET.getText().toString();
if(username_ET.length() > 0 && password_ET.length() > 0) {
String uName = null;
String uPassword = null;
if (sharedPreferences.contains(userName)) {
uName = sharedPreferences.getString("userName", "");
}
if (sharedPreferences.contains(password)) {
uPassword = sharedPreferences.getString("password", "");
}
//start new activity
if (userName.equals(uName) && password.equals(uPassword)) {
Toast.makeText(getActivity(), "You entered: " + uName, Toast.LENGTH_SHORT).show();
Intent i = new Intent(getActivity(), DiaryActivity.class);
startActivity(i);
}
}
//String userName = sharedPreferences.getString("userName", "");
//String pw = sharedPreferences.getString("password", "");
//sharedPreferences.getString("uid", "");
//sharedPreferences.getString("pwd", "");
}
});
register_btn.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
FragmentManager FM = getFragmentManager();
FragmentTransaction FT = FM.beginTransaction();
RegisterFragment RG = new RegisterFragment();
FT.replace(R.id.register_fragment_id, RG);
FT.commit();
}
});
return v;
}
// getter for the user name
public String getUsername() {
String str = username_ET.getText().toString();
return str;// returns the user name
}// end of getUsername()
private boolean passwordCorrect() {
// prefix the key with the user name
if (sharedPreferences.contains(username + "_" + KEY_UID)) {
String pwd = sharedPreferences.getString(username + "_"
+ KEY_PASSWORD, "");
if (pwd.equals(password_ET.getText().toString()))
return true;
}
return false;
}
// getter for the user name
private boolean userExists() {
// prefix the key with the user name
if (sharedPreferences.contains(username + "_" + KEY_UID)) {
String uID = sharedPreferences.getString(username + "_" + KEY_UID,
"");
if (uID.equals(username_ET.getText().toString()))
return true;
}
return false;
}// end of userExists()
private boolean isValid() {
boolean idEmpty = false;
boolean passEmpty = false;
if ((username_ET.getText().toString().isEmpty())) {
idEmpty = true;
String text = getResources()
.getString(R.string.error_emptyUsername);
Toast.makeText(getActivity().getApplicationContext(), text, Toast.LENGTH_SHORT)
.show();
}
if ((password_ET.getText().toString().isEmpty())) {
passEmpty = true;
String text = getResources()
.getString(R.string.error_emptyPassword);
Toast.makeText(getActivity().getApplicationContext(), text, Toast.LENGTH_SHORT)
.show();
}
return !(idEmpty | passEmpty);
}// end of isValid()
}
答案 0 :(得分：1)
您正在使用其他密钥在LoginFragment中获取数据。即 您正在尝试访问不存在的首选项。更改您的代码，如下所示
LoginFragment：
private boolean userExists() {
String uID = sharedPreferences.getString("userName" + "_" + KEY_UID, "");
return (uID.equals(username_ET.getText().toString()))
}
也可以将其更改为密码。